Reworking thcolor.

author: Thomas Touhey <thomas@touhey.fr> 2021-09-11 21:09:06 +0200
committer: Thomas Touhey <thomas@touhey.fr> 2021-09-11 21:09:06 +0200
commit: 5f54b6757abee47ee883d353e4aeda9c56dd6c89 (patch)
tree: 20bff9751f36f0bb5d4504f1961e51d033add177
parent: b3edd31df8c96035d70c0216e444d6dd9951699f (diff)
34 files changed, 2746 insertions, 1710 deletions
diff --git a/.python-version b/.python-version
index 0b2eb36..11aaa06 100644
--- a/.python-version
+++ b/.python-version
@@ -1 +1 @@
-3.7.2
+3.9.5
diff --git a/Makefile b/Makefile
index 3d840bc..be3a816 100755
--- a/Makefile
+++ b/Makefile
@@ -14,6 +14,8 @@ update:
 docs:
 	@$(ST) build_sphinx
 
+check:
+	@$(PE) flake8
 checkdocs:
 	@$(ST) checkdocs
 
diff --git a/Pipfile b/Pipfile
index 2b67cce..3ed277a 100644
--- a/Pipfile
+++ b/Pipfile
@@ -4,13 +4,18 @@ verify_ssl = true
 name = 'pypi'
 
 [requires]
-python_version = '3.7'
+python_version = '3.9'
 
 [packages]
 regex = '*'
 
 [dev-packages]
 sphinx = '*'
+sphinx_rtd_theme = '*'
+sphinx-autodoc-typehints = "*"
+sphinx-autobuild = '*'
 "collective.checkdocs" = '*'
 pudb = '*'
 pytest = '*'
+flake8 = '*'
+flake8-tabs = '*'
diff --git a/Pipfile.lock b/Pipfile.lock
index 9758a34..d62723b 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,11 +1,11 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "0376534457dcacd720d6a912bf87bdf10739752646bf34d5c06ef3de9863f538"
+            "sha256": "fd1fa6f73d5accb39252360fbedf214260d693b76bfbef4b5147055b376e2624"
         },
         "pipfile-spec": 6,
         "requires": {
-            "python_version": "3.7"
+            "python_version": "3.9"
         },
         "sources": [
             {
@@ -18,18 +18,50 @@
     "default": {
         "regex": {
             "hashes": [
-                "sha256:020429dcf9b76cc7648a99c81b3a70154e45afebc81e0b85364457fe83b525e4",
-                "sha256:0552802b1c3f3c7e4fee8c85e904a13c48226020aa1a0593246888a1ac55aaaf",
-                "sha256:308965a80b92e1fec263ac1e4f1094317809a72bc4d26be2ec8a5fd026301175",
-                "sha256:4d627feef04eb626397aa7bdec772774f53d63a1dc7cc5ee4d1bd2786a769d19",
-                "sha256:93d1f9fcb1d25e0b4bd622eeba95b080262e7f8f55e5b43c76b8a5677e67334c",
-                "sha256:c3859bbf29b1345d694f069ddfe53d6907b0393fda5e3794c800ad02902d78e9",
-                "sha256:d56ce4c7b1a189094b9bee3b81c4aeb3f1ba3e375e91627ec8561b6ab483d0a8",
-                "sha256:ebc5ef4e10fa3312fa1967dc0a894e6bd985a046768171f042ac3974fadc9680",
-                "sha256:f9cd39066048066a4abe4c18fb213bc541339728005e72263f023742fb912585"
+                "sha256:04f6b9749e335bb0d2f68c707f23bb1773c3fb6ecd10edf0f04df12a8920d468",
+                "sha256:08d74bfaa4c7731b8dac0a992c63673a2782758f7cfad34cf9c1b9184f911354",
+                "sha256:0fc1f8f06977c2d4f5e3d3f0d4a08089be783973fc6b6e278bde01f0544ff308",
+                "sha256:121f4b3185feaade3f85f70294aef3f777199e9b5c0c0245c774ae884b110a2d",
+                "sha256:1413b5022ed6ac0d504ba425ef02549a57d0f4276de58e3ab7e82437892704fc",
+                "sha256:1743345e30917e8c574f273f51679c294effba6ad372db1967852f12c76759d8",
+                "sha256:28fc475f560d8f67cc8767b94db4c9440210f6958495aeae70fac8faec631797",
+                "sha256:31a99a4796bf5aefc8351e98507b09e1b09115574f7c9dbb9cf2111f7220d2e2",
+                "sha256:328a1fad67445550b982caa2a2a850da5989fd6595e858f02d04636e7f8b0b13",
+                "sha256:473858730ef6d6ff7f7d5f19452184cd0caa062a20047f6d6f3e135a4648865d",
+                "sha256:4cde065ab33bcaab774d84096fae266d9301d1a2f5519d7bd58fc55274afbf7a",
+                "sha256:5f6a808044faae658f546dd5f525e921de9fa409de7a5570865467f03a626fc0",
+                "sha256:610b690b406653c84b7cb6091facb3033500ee81089867ee7d59e675f9ca2b73",
+                "sha256:66256b6391c057305e5ae9209941ef63c33a476b73772ca967d4a2df70520ec1",
+                "sha256:6eebf512aa90751d5ef6a7c2ac9d60113f32e86e5687326a50d7686e309f66ed",
+                "sha256:79aef6b5cd41feff359acaf98e040844613ff5298d0d19c455b3d9ae0bc8c35a",
+                "sha256:808ee5834e06f57978da3e003ad9d6292de69d2bf6263662a1a8ae30788e080b",
+                "sha256:8e44769068d33e0ea6ccdf4b84d80c5afffe5207aa4d1881a629cf0ef3ec398f",
+                "sha256:999ad08220467b6ad4bd3dd34e65329dd5d0df9b31e47106105e407954965256",
+                "sha256:9b006628fe43aa69259ec04ca258d88ed19b64791693df59c422b607b6ece8bb",
+                "sha256:9d05ad5367c90814099000442b2125535e9d77581855b9bee8780f1b41f2b1a2",
+                "sha256:a577a21de2ef8059b58f79ff76a4da81c45a75fe0bfb09bc8b7bb4293fa18983",
+                "sha256:a617593aeacc7a691cc4af4a4410031654f2909053bd8c8e7db837f179a630eb",
+                "sha256:abb48494d88e8a82601af905143e0de838c776c1241d92021e9256d5515b3645",
+                "sha256:ac88856a8cbccfc14f1b2d0b829af354cc1743cb375e7f04251ae73b2af6adf8",
+                "sha256:b4c220a1fe0d2c622493b0a1fd48f8f991998fb447d3cd368033a4b86cf1127a",
+                "sha256:b844fb09bd9936ed158ff9df0ab601e2045b316b17aa8b931857365ea8586906",
+                "sha256:bdc178caebd0f338d57ae445ef8e9b737ddf8fbc3ea187603f65aec5b041248f",
+                "sha256:c206587c83e795d417ed3adc8453a791f6d36b67c81416676cad053b4104152c",
+                "sha256:c61dcc1cf9fd165127a2853e2c31eb4fb961a4f26b394ac9fe5669c7a6592892",
+                "sha256:c7cb4c512d2d3b0870e00fbbac2f291d4b4bf2634d59a31176a87afe2777c6f0",
+                "sha256:d4a332404baa6665b54e5d283b4262f41f2103c255897084ec8f5487ce7b9e8e",
+                "sha256:d5111d4c843d80202e62b4fdbb4920db1dcee4f9366d6b03294f45ed7b18b42e",
+                "sha256:e1e8406b895aba6caa63d9fd1b6b1700d7e4825f78ccb1e5260551d168db38ed",
+                "sha256:e8690ed94481f219a7a967c118abaf71ccc440f69acd583cab721b90eeedb77c",
+                "sha256:ed283ab3a01d8b53de3a05bfdf4473ae24e43caee7dcb5584e86f3f3e5ab4374",
+                "sha256:ed4b50355b066796dacdd1cf538f2ce57275d001838f9b132fab80b75e8c84dd",
+                "sha256:ee329d0387b5b41a5dddbb6243a21cb7896587a651bebb957e2d2bb8b63c0791",
+                "sha256:f3bf1bc02bc421047bfec3343729c4bbbea42605bcfd6d6bfe2c07ade8b12d2a",
+                "sha256:f585cbbeecb35f35609edccb95efd95a3e35824cd7752b586503f7e6087303f1",
+                "sha256:f60667673ff9c249709160529ab39667d1ae9fd38634e006bec95611f632e759"
             ],
             "index": "pypi",
-            "version": "==2019.4.14"
+            "version": "==2021.8.28"
         }
     },
     "develop": {
@@ -40,40 +72,36 @@
             ],
             "version": "==0.7.12"
         },
-        "atomicwrites": {
-            "hashes": [
-                "sha256:03472c30eb2c5d1ba9227e4c2ca66ab8287fbfbbda3888aa93dc2e28fc6811b4",
-                "sha256:75a9445bac02d8d058d5e1fe689654ba5a6556a1dfd8ce6ec55a0ed79866cfa6"
-            ],
-            "version": "==1.3.0"
-        },
         "attrs": {
             "hashes": [
-                "sha256:69c0dbf2ed392de1cb5ec704444b08a5ef81680a61cb899dc08127123af36a79",
-                "sha256:f0b870f674851ecbfbbbd364d6b5cbdff9dcedbc7f3f5e18a6891057f21fe399"
+                "sha256:149e90d6d8ac20db7a955ad60cf0e6881a3f20d37096140088356da6c716b0b1",
+                "sha256:ef6aaac3ca6cd92904cdd0d83f629a15f18053ec84e6432106f7a4d04ae4f5fb"
             ],
-            "version": "==19.1.0"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==21.2.0"
         },
         "babel": {
             "hashes": [
-                "sha256:6778d85147d5d85345c14a26aada5e478ab04e39b078b0745ee6870c2b5cf669",
-                "sha256:8cba50f48c529ca3fa18cf81fa9403be176d374ac4d60738b839122dfaaa3d23"
+                "sha256:ab49e12b91d937cd11f0b67cb259a57ab4ad2b59ac7a3b41d6c06c0ac5b0def9",
+                "sha256:bc0c176f9f6a994582230df350aa6e05ba2ebe4b3ac317eab29d9be5d2768da0"
             ],
-            "version": "==2.6.0"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==2.9.1"
         },
         "certifi": {
             "hashes": [
-                "sha256:59b7658e26ca9c7339e00f8f4636cdfe59d34fa37b9b04f6f9e9926b3cece1a5",
-                "sha256:b26104d6835d1f5e49452a26eb2ff87fe7090b89dfcaee5ea2212697e1e1d7ae"
+                "sha256:2bbf76fd432960138b3ef6dda3dde0544f27cbf8546c458e60baf371917ba9ee",
+                "sha256:50b1e4f8446b06f41be7dd6338db18e0990601dce795c2b1686458aa7e8fa7d8"
             ],
-            "version": "==2019.3.9"
+            "version": "==2021.5.30"
         },
-        "chardet": {
+        "charset-normalizer": {
             "hashes": [
-                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
-                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
+                "sha256:0c8911edd15d19223366a194a513099a302055a962bca2cec0f54b8b63175d8b",
+                "sha256:f23667ebe1084be45f6ae0538e4a5a865206544097e4e8bbcacf42cd02a348f3"
             ],
-            "version": "==3.0.4"
+            "markers": "python_version >= '3'",
+            "version": "==2.0.4"
         },
         "collective.checkdocs": {
             "hashes": [
@@ -82,216 +110,414 @@
             "index": "pypi",
             "version": "==0.2"
         },
+        "colorama": {
+            "hashes": [
+                "sha256:5941b2b48a20143d2267e95b1c2a7603ce057ee39fd88e7329b0c292aa16869b",
+                "sha256:9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==0.4.4"
+        },
         "docutils": {
             "hashes": [
-                "sha256:02aec4bd92ab067f6ff27a38a38a41173bf01bed8f89157768c1573f53e474a6",
-                "sha256:51e64ef2ebfb29cae1faa133b3710143496eca21c530f3f71424d77687764274",
-                "sha256:7a4bd47eaf6596e1295ecb11361139febe29b084a87bf005bf899f9a42edc3c6"
+                "sha256:0c5b78adfbf7762415433f5515cd5c9e762339e23369dbe8000d84a4bf4ab3af",
+                "sha256:c2de3a60e9e7d07be26b7f2b00ca0309c207e06c100f9cc2a94931fc75a478fc"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'",
+            "version": "==0.16"
+        },
+        "editorconfig": {
+            "hashes": [
+                "sha256:57f8ce78afcba15c8b18d46b5170848c88d56fd38f05c2ec60dbbfcb8996e89e",
+                "sha256:6b0851425aa875b08b16789ee0eeadbd4ab59666e9ebe728e526314c4a2e52c1"
+            ],
+            "version": "==0.12.3"
+        },
+        "flake8": {
+            "hashes": [
+                "sha256:07528381786f2a6237b061f6e96610a4167b226cb926e2aa2b6b1d78057c576b",
+                "sha256:bf8fd333346d844f616e8d47905ef3a3384edae6b4e9beb0c5101e25e3110907"
+            ],
+            "index": "pypi",
+            "version": "==3.9.2"
+        },
+        "flake8-tabs": {
+            "hashes": [
+                "sha256:e36c0f2038d709961510b9a80a685b28db87df6cfb1309b111d6be41e79a669b",
+                "sha256:f11c4b8a1537d67014c24f5296118e54b78fc43204b740e28283fa8e165130ef"
             ],
-            "version": "==0.14"
+            "index": "pypi",
+            "version": "==2.3.2"
         },
         "idna": {
             "hashes": [
-                "sha256:c357b3f628cf53ae2c4c05627ecc484553142ca23264e593d327bcde5e9c3407",
-                "sha256:ea8b7f6188e6fa117537c3df7da9fc686d485087abf6ac197f9c46432f7e4a3c"
+                "sha256:14475042e284991034cb48e06f6851428fb14c4dc953acd9be9a5e95c7b6dd7a",
+                "sha256:467fbad99067910785144ce333826c71fb0e63a425657295239737f7ecd125f3"
             ],
-            "version": "==2.8"
+            "markers": "python_version >= '3'",
+            "version": "==3.2"
         },
         "imagesize": {
             "hashes": [
-                "sha256:3f349de3eb99145973fefb7dbe38554414e5c30abd0c8e4b970a7c9d09f3a1d8",
-                "sha256:f3832918bc3c66617f92e35f5d70729187676313caa60c187eb0f28b8fe5e3b5"
+                "sha256:6965f19a6a2039c7d48bca7dba2473069ff854c36ae6f19d2cde309d998228a1",
+                "sha256:b1f6b5a4eab1f73479a50fb79fcf729514a900c341d8503d62a62dbc4127a2b1"
+            ],
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==1.2.0"
+        },
+        "iniconfig": {
+            "hashes": [
+                "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3",
+                "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"
+            ],
+            "version": "==1.1.1"
+        },
+        "jedi": {
+            "hashes": [
+                "sha256:18456d83f65f400ab0c2d3319e48520420ef43b23a086fdc05dff34132f0fb93",
+                "sha256:92550a404bad8afed881a137ec9a461fed49eca661414be45059329614ed0707"
             ],
-            "version": "==1.1.0"
+            "markers": "python_version >= '3.6'",
+            "version": "==0.18.0"
         },
         "jinja2": {
             "hashes": [
-                "sha256:065c4f02ebe7f7cf559e49ee5a95fb800a9e4528727aec6f24402a5374c65013",
-                "sha256:14dd6caf1527abb21f08f86c784eac40853ba93edb79552aa1e4b8aef1b61c7b"
+                "sha256:1f06f2da51e7b56b8f238affdd6b4e2c61e39598a378cc49345bc1bd42a978a4",
+                "sha256:703f484b47a6af502e743c9122595cc812b0271f661722403114f71a79d0f5a4"
             ],
-            "version": "==2.10.1"
+            "markers": "python_version >= '3.6'",
+            "version": "==3.0.1"
         },
-        "markupsafe": {
+        "livereload": {
             "hashes": [
-                "sha256:00bc623926325b26bb9605ae9eae8a215691f33cae5df11ca5424f06f2d1f473",
-                "sha256:09027a7803a62ca78792ad89403b1b7a73a01c8cb65909cd876f7fcebd79b161",
-                "sha256:09c4b7f37d6c648cb13f9230d847adf22f8171b1ccc4d5682398e77f40309235",
-                "sha256:1027c282dad077d0bae18be6794e6b6b8c91d58ed8a8d89a89d59693b9131db5",
-                "sha256:24982cc2533820871eba85ba648cd53d8623687ff11cbb805be4ff7b4c971aff",
-                "sha256:29872e92839765e546828bb7754a68c418d927cd064fd4708fab9fe9c8bb116b",
-                "sha256:43a55c2930bbc139570ac2452adf3d70cdbb3cfe5912c71cdce1c2c6bbd9c5d1",
-                "sha256:46c99d2de99945ec5cb54f23c8cd5689f6d7177305ebff350a58ce5f8de1669e",
-                "sha256:500d4957e52ddc3351cabf489e79c91c17f6e0899158447047588650b5e69183",
-                "sha256:535f6fc4d397c1563d08b88e485c3496cf5784e927af890fb3c3aac7f933ec66",
-                "sha256:62fe6c95e3ec8a7fad637b7f3d372c15ec1caa01ab47926cfdf7a75b40e0eac1",
-                "sha256:6dd73240d2af64df90aa7c4e7481e23825ea70af4b4922f8ede5b9e35f78a3b1",
-                "sha256:717ba8fe3ae9cc0006d7c451f0bb265ee07739daf76355d06366154ee68d221e",
-                "sha256:79855e1c5b8da654cf486b830bd42c06e8780cea587384cf6545b7d9ac013a0b",
-                "sha256:7c1699dfe0cf8ff607dbdcc1e9b9af1755371f92a68f706051cc8c37d447c905",
-                "sha256:88e5fcfb52ee7b911e8bb6d6aa2fd21fbecc674eadd44118a9cc3863f938e735",
-                "sha256:8defac2f2ccd6805ebf65f5eeb132adcf2ab57aa11fdf4c0dd5169a004710e7d",
-                "sha256:98c7086708b163d425c67c7a91bad6e466bb99d797aa64f965e9d25c12111a5e",
-                "sha256:9add70b36c5666a2ed02b43b335fe19002ee5235efd4b8a89bfcf9005bebac0d",
-                "sha256:9bf40443012702a1d2070043cb6291650a0841ece432556f784f004937f0f32c",
-                "sha256:ade5e387d2ad0d7ebf59146cc00c8044acbd863725f887353a10df825fc8ae21",
-                "sha256:b00c1de48212e4cc9603895652c5c410df699856a2853135b3967591e4beebc2",
-                "sha256:b1282f8c00509d99fef04d8ba936b156d419be841854fe901d8ae224c59f0be5",
-                "sha256:b2051432115498d3562c084a49bba65d97cf251f5a331c64a12ee7e04dacc51b",
-                "sha256:ba59edeaa2fc6114428f1637ffff42da1e311e29382d81b339c1817d37ec93c6",
-                "sha256:c8716a48d94b06bb3b2524c2b77e055fb313aeb4ea620c8dd03a105574ba704f",
-                "sha256:cd5df75523866410809ca100dc9681e301e3c27567cf498077e8551b6d20e42f",
-                "sha256:e249096428b3ae81b08327a63a485ad0878de3fb939049038579ac0ef61e17e7"
+                "sha256:776f2f865e59fde56490a56bcc6773b6917366bce0c267c60ee8aaf1a0959869"
             ],
-            "version": "==1.1.1"
+            "version": "==2.6.3"
+        },
+        "markupsafe": {
+            "hashes": [
+                "sha256:01a9b8ea66f1658938f65b93a85ebe8bc016e6769611be228d797c9d998dd298",
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-                "sha256:c0efb33f8052c04fd7a26c0a07f1678e8512e0faec19f4aa8f2473a8b81d5227",
-                "sha256:db6615af393650bf1151a6cd39120c29abaf93cc60db8c48eb2dddbfdc3a9768"
-            ],
-            "version": "==1.1.3"
+                "sha256:352a9a00ae864471d3a7ead8d7d79f5fc0b57e8b3f95e9867eb9eb28999b92fd",
+                "sha256:aa5f6de5dfdf809ef505c4895e51ef5c9eac17d0f287933eb49ec495280b6952"
+            ],
+            "markers": "python_version >= '3.5'",
+            "version": "==1.1.5"
+        },
+        "toml": {
+            "hashes": [
+                "sha256:806143ae5bfb6a3c6e736a764057db0e6a0e05e338b5630894a5f779cabb4f9b",
+                "sha256:b3bda1d108d5dd99f4a20d24d9c348e91c4db7ab1b749200bded2f839ccbe68f"
+            ],
+            "markers": "python_version >= '2.6' and python_version not in '3.0, 3.1, 3.2, 3.3'",
+            "version": "==0.10.2"
+        },
+        "tornado": {
+            "hashes": [
+                "sha256:0a00ff4561e2929a2c37ce706cb8233b7907e0cdc22eab98888aca5dd3775feb",
+                "sha256:0d321a39c36e5f2c4ff12b4ed58d41390460f798422c4504e09eb5678e09998c",
+                "sha256:1e8225a1070cd8eec59a996c43229fe8f95689cb16e552d130b9793cb570a288",
+                "sha256:20241b3cb4f425e971cb0a8e4ffc9b0a861530ae3c52f2b0434e6c1b57e9fd95",
+                "sha256:25ad220258349a12ae87ede08a7b04aca51237721f63b1808d39bdb4b2164558",
+                "sha256:33892118b165401f291070100d6d09359ca74addda679b60390b09f8ef325ffe",
+                "sha256:33c6e81d7bd55b468d2e793517c909b139960b6c790a60b7991b9b6b76fb9791",
+                "sha256:3447475585bae2e77ecb832fc0300c3695516a47d46cefa0528181a34c5b9d3d",
+                "sha256:34ca2dac9e4d7afb0bed4677512e36a52f09caa6fded70b4e3e1c89dbd92c326",
+                "sha256:3e63498f680547ed24d2c71e6497f24bca791aca2fe116dbc2bd0ac7f191691b",
+                "sha256:548430be2740e327b3fe0201abe471f314741efcb0067ec4f2d7dcfb4825f3e4",
+                "sha256:6196a5c39286cc37c024cd78834fb9345e464525d8991c21e908cc046d1cc02c",
+                "sha256:61b32d06ae8a036a6607805e6720ef00a3c98207038444ba7fd3d169cd998910",
+                "sha256:6286efab1ed6e74b7028327365cf7346b1d777d63ab30e21a0f4d5b275fc17d5",
+                "sha256:65d98939f1a2e74b58839f8c4dab3b6b3c1ce84972ae712be02845e65391ac7c",
+                "sha256:66324e4e1beede9ac79e60f88de548da58b1f8ab4b2f1354d8375774f997e6c0",
+                "sha256:6c77c9937962577a6a76917845d06af6ab9197702a42e1346d8ae2e76b5e3675",
+                "sha256:70dec29e8ac485dbf57481baee40781c63e381bebea080991893cd297742b8fd",
+                "sha256:7250a3fa399f08ec9cb3f7b1b987955d17e044f1ade821b32e5f435130250d7f",
+                "sha256:748290bf9112b581c525e6e6d3820621ff020ed95af6f17fedef416b27ed564c",
+                "sha256:7da13da6f985aab7f6f28debab00c67ff9cbacd588e8477034c0652ac141feea",
+                "sha256:8f959b26f2634a091bb42241c3ed8d3cedb506e7c27b8dd5c7b9f745318ddbb6",
+                "sha256:9de9e5188a782be6b1ce866e8a51bc76a0fbaa0e16613823fc38e4fc2556ad05",
+                "sha256:a48900ecea1cbb71b8c71c620dee15b62f85f7c14189bdeee54966fbd9a0c5bd",
+                "sha256:b87936fd2c317b6ee08a5741ea06b9d11a6074ef4cc42e031bc6403f82a32575",
+                "sha256:c77da1263aa361938476f04c4b6c8916001b90b2c2fdd92d8d535e1af48fba5a",
+                "sha256:cb5ec8eead331e3bb4ce8066cf06d2dfef1bfb1b2a73082dfe8a161301b76e37",
+                "sha256:cc0ee35043162abbf717b7df924597ade8e5395e7b66d18270116f8745ceb795",
+                "sha256:d14d30e7f46a0476efb0deb5b61343b1526f73ebb5ed84f23dc794bdb88f9d9f",
+                "sha256:d371e811d6b156d82aa5f9a4e08b58debf97c302a35714f6f45e35139c332e32",
+                "sha256:d3d20ea5782ba63ed13bc2b8c291a053c8d807a8fa927d941bd718468f7b950c",
+                "sha256:d3f7594930c423fd9f5d1a76bee85a2c36fd8b4b16921cae7e965f22575e9c01",
+                "sha256:dcef026f608f678c118779cd6591c8af6e9b4155c44e0d1bc0c87c036fb8c8c4",
+                "sha256:e0791ac58d91ac58f694d8d2957884df8e4e2f6687cdf367ef7eb7497f79eaa2",
+                "sha256:e385b637ac3acaae8022e7e47dfa7b83d3620e432e3ecb9a3f7f58f150e50921",
+                "sha256:e519d64089b0876c7b467274468709dadf11e41d65f63bba207e04217f47c085",
+                "sha256:e7229e60ac41a1202444497ddde70a48d33909e484f96eb0da9baf8dc68541df",
+                "sha256:ed3ad863b1b40cd1d4bd21e7498329ccaece75db5a5bf58cd3c9f130843e7102",
+                "sha256:f0ba29bafd8e7e22920567ce0d232c26d4d47c8b5cf4ed7b562b5db39fa199c5",
+                "sha256:fa2ba70284fa42c2a5ecb35e322e68823288a4251f9ba9cc77be04ae15eada68",
+                "sha256:fba85b6cd9c39be262fcd23865652920832b61583de2a2ca907dbd8e8a8c81e5"
+            ],
+            "markers": "python_version >= '3.5'",
+            "version": "==6.1"
         },
         "urllib3": {
             "hashes": [
-                "sha256:2393a695cd12afedd0dcb26fe5d50d0cf248e5a66f75dbd89a3d4eb333a61af4",
-                "sha256:a637e5fae88995b256e3409dc4d52c2e2e0ba32c42a6365fee8bbd2238de3cfb"
+                "sha256:39fb8672126159acb139a7718dd10806104dec1e2f0f6c88aab05d17df10c8d4",
+                "sha256:f57b4c16c62fa2760b7e3d97c35b255512fb6b59a259730f36ba32ce9f8e342f"
             ],
-            "version": "==1.24.3"
+            "markers": "python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4' and python_version < '4'",
+            "version": "==1.26.6"
         },
         "urwid": {
             "hashes": [
-                "sha256:644d3e3900867161a2fc9287a9762753d66bd194754679adb26aede559bcccbc"
+                "sha256:588bee9c1cb208d0906a9f73c613d2bd32c3ed3702012f51efe318a3f2127eae"
             ],
-            "version": "==2.0.1"
+            "version": "==2.1.2"
         }
     }
 }
diff --git a/docs/Makefile b/docs/Makefile
index 28d11c9..cd5fe80 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -2,12 +2,14 @@
 #
 
 # You can set these variables from the command line.
+
+PE            = pipenv run
 SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build
-SPHINXWATCH   = sphinx-autobuild
+SPHINXBUILD   = $(PE) sphinx-build
+SPHINXWATCH   = $(PE) sphinx-autobuild
 SOURCEDIR     = .
 BUILDDIR      = _build
-WEBROOT       = thcolor.touhey.pro:thcolor_doc
+WEBROOT       = hercule:thcolor/docs
 
 # Put it first so that "make" without argument is like "make help".
 help:
@@ -22,7 +24,8 @@ help:
 
 # Livehtml build.
 livehtml:
-	$(SPHINXWATCH) -b html -z ../thcolor $(SPHINXOPTS) . $(BUILDDIR)/html
+	$(SPHINXWATCH) -b html --watch ../thcolor --ignore "**/.*.kate-swp" \
+		$(SPHINXOPTS) . $(BUILDDIR)/html
 
 .PHONY: livehtml
 
diff --git a/docs/angles.rst b/docs/angles.rst
deleted file mode 100644
index 71d52a9..0000000
--- a/docs/angles.rst
+++ /dev/null
@@ -1,12 +0,0 @@
-Angles
-======
-
-Some color representations use angles as some of their properties. Angles can
-have one of the following types:
-
-.. autoclass:: thcolor.Angle.Type
-
-Angles in ``thcolor`` are instances of the following class:
-
-.. autoclass:: thcolor.Angle
-	:members: type, degrees, gradiants, radiants, turns
diff --git a/docs/api.rst b/docs/api.rst
new file mode 100644
index 0000000..2ad7a43
--- /dev/null
+++ b/docs/api.rst
@@ -0,0 +1,10 @@
+API Reference
+=============
+
+If you are looking for information on a specific function, class or method,
+this part of the documentation is for you.
+
+.. toctree::
+
+	api/angles
+	api/colors
diff --git a/docs/api/angles.rst b/docs/api/angles.rst
new file mode 100644
index 0000000..609bb33
--- /dev/null
+++ b/docs/api/angles.rst
@@ -0,0 +1,24 @@
+Angles
+======
+
+.. py:module:: thcolor.angles
+
+Some color representations use angles as some of their properties. The base
+class for angles is the following:
+
+.. autoclass:: Angle
+	:members: asdegrees, asgradians, asradians, asturns
+
+Subclasses are the following:
+
+.. autoclass:: DegreesAngle
+	:members: degrees
+
+.. autoclass:: GradiansAngle
+	:members: gradians
+
+.. autoclass:: RadiansAngle
+	:members: radians
+
+.. autoclass:: TurnsAngle
+	:members: turns
diff --git a/docs/api/colors.rst b/docs/api/colors.rst
new file mode 100644
index 0000000..937cd61
--- /dev/null
+++ b/docs/api/colors.rst
@@ -0,0 +1,34 @@
+Colors
+======
+
+.. py:module:: thcolor.colors
+
+The base class for colors is the following:
+
+.. autoclass:: Color
+	:members: alpha, assrgb, ashsl, ashwb, ascmyk, aslab, aslch, asxyz,
+	          replace, darker, lighter, desaturate, saturate,
+	          css, from_text
+
+Subclasses are the following:
+
+.. autoclass:: SRGBColor
+	:members: red, green, blue, alpha, frombytes, fromnetscapecolorname
+
+.. autoclass:: HSLColor
+	:members: hue, saturation, lightness, alpha
+
+.. autoclass:: HWBColor
+	:members: hue, whiteness, blackness, alpha
+
+.. autoclass:: CMYKColor
+	:members: cyan, magenta, yellow, black, alpha
+
+.. autoclass:: LABColor
+	:members: lightness, a, b, alpha
+
+.. autoclass:: LCHColor
+	:members: lightness, chroma, hue, alpha
+
+.. autoclass:: XYZColor
+	:members: x, y, z, alpha
diff --git a/docs/colors.rst b/docs/colors.rst
deleted file mode 100644
index 7bff8d1..0000000
--- a/docs/colors.rst
+++ /dev/null
@@ -1,16 +0,0 @@
-Colors
-======
-
-Colors can have one of the following types:
-
-.. autoclass:: thcolor.Color.Type
-
-RGB colors can have one of the following profiles:
-
-.. autoclass:: thcolor.Color.Profile
-
-Colors are represented in ``thcolor`` as instances of the following class:
-
-.. autoclass:: thcolor.Color
-	:members: type, rgb, rgba, hls, hlsa, hwb, hwba, cmyk, cmyka, lab, laba,
-	          lch, lcha, xyz, xyza, css
diff --git a/docs/conf.py b/docs/conf.py
index 0627b7e..7fbab7d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -27,12 +27,14 @@ author = 'Thomas Touhey'
 # The full version, including alpha/beta/rc tags
 
 def _get_release():
-	from os.path import dirname, join
-	from pkg_resources import find_distributions as find_dist
+	from os.path import dirname, join, normpath
+	from pkg_resources import Environment as _Environment
 
-	module_path = join(dirname(__file__), '..')
-	dist = next(find_dist(module_path, True))
-	return dist.version
+	module_path = normpath(join(dirname(__file__), '..'))
+	env = _Environment(module_path)
+	env.scan()
+	mod = env['thcolor'][0]
+	return mod.version
 
 release = _get_release()
 
@@ -42,9 +44,13 @@ release = _get_release()
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-	'sphinx.ext.autodoc'
+	'sphinx.ext.autodoc',
+	'sphinx.ext.todo',
+	'sphinx_autodoc_typehints',
 ]
 
+todo_include_todos = True
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = []
 
diff --git a/docs/discuss.rst b/docs/discuss.rst
new file mode 100644
index 0000000..d7e2055
--- /dev/null
+++ b/docs/discuss.rst
@@ -0,0 +1,10 @@
+Discussion topics
+=================
+
+thcolor has a number of concepts necessary for a full understanding of its
+conception and an efficient use of it. You can find these concepts and
+discussion topics in the following sections.
+
+.. toctree::
+
+	discuss/color-expressions
diff --git a/docs/discuss/color-expressions.rst b/docs/discuss/color-expressions.rst
new file mode 100644
index 0000000..0109057
--- /dev/null
+++ b/docs/discuss/color-expressions.rst
@@ -0,0 +1,53 @@
+.. _expr:
+
+Expressions
+===========
+
+One of the aims of thcolor was to decode text-based expressions
+representing colors with possibilities challenging and even outdo
+CSS color expression possibilities. This is what the following static method
+is for:
+
+Expression concepts
+-------------------
+
+The goal of these expressions was to embrace and extend CSS syntax, so they
+are basically either basic expressions or function calls, with the following
+argument types:
+
+ * Numbers.
+ * Percentages.
+ * Angles.
+ * Colors.
+
+These elements are separated by separators (either commas, slashes, or simple
+spaces) and can be passed to functions, and the calls themselves can be passed
+to other functions. A function call is made in the following fashion:
+
+::
+
+	<function name>([<number | percentage | angle | color> [<separator> …]])
+
+If at least one separator (even simple spaces) are required between arguments,
+extraneous separators between and after the arguments are ignored. Other than
+if spaces are used as separators, spaces around the parenthesis or the
+separators (and "between" the separators as spaces are recognized as
+separators) are ignored.
+
+Here are some example calls:
+
+::
+
+	rgb(1, 2, 3)
+	rgb  ( 1 22 //// 242 , 50.0% ,/,)
+	hsl (0 1 50 % / 22)
+	gray ( red( #123456 )/0.2/)
+
+Defining a reference
+--------------------
+
+Functions and color names are defined in a reference:
+
+.. todo::
+
+	More about this.
diff --git a/docs/expressions.rst b/docs/expressions.rst
deleted file mode 100644
index 6f9e645..0000000
--- a/docs/expressions.rst
+++ /dev/null
@@ -1,89 +0,0 @@
-.. _expr:
-
-Expressions
-===========
-
-One of the aims of the ``thcolor`` module was to decode text-based expressions
-representing colors with possibilities challenging and even outdo
-CSS color expression possibilities. This is what the following static method
-is for:
-
-.. automethod:: thcolor.Color.from_text
-
-Expression concepts
--------------------
-
-The goal of these expressions was to embrace and extend CSS syntax, so they
-are basically either basic expressions or function calls, with the following
-argument types:
-
-.. autoclass:: thcolor.Reference.number
-	:members:
-
-.. autoclass:: thcolor.Reference.percentage
-	:members:
-
-.. autoclass:: thcolor.Reference.angle
-	:members:
-
-.. autoclass:: thcolor.Reference.color
-	:members:
-
-These elements are separated by separators (either commas, slashes, or simple
-spaces) and can be passed to functions, and the calls themselves can be passed
-to other functions. A function call is made in the following fashion:
-
-::
-
-	<function name>(<number | percentage | angle | color> [<separator> …])
-
-If at least one separator (even simple spaces) are required between arguments,
-extraneous separators between and after the arguments are ignored. Other than
-if spaces are used as separators, spaces around the parenthesis or the
-separators (and "between" the separators as spaces are recognized as
-separators) are ignored.
-
-Here are some example calls:
-
-::
-
-	rgb(1, 2, 3)
-	rgb  ( 1 22 //// 242 , 50.0% ,/,)
-	hsl (0 1 50 % / 22)
-	gray ( red( #123456 )/0.2/)
-
-In case of incorrectly formatted string, the following exception is returned:
-
-.. autoexception:: thcolor.ColorExpressionDecodingError
-	:members:
-
-Defining a reference
---------------------
-
-Functions and color names are defined in a reference:
-
-- color names are defined behind an overload of
-  :meth:`thcolor.Reference._color`.
-- functions are defined as reference class methods and use `type hints
-  <https://www.python.org/dev/peps/pep-0484/>`_ to describe the types
-  they are expecting.
-
-The reference must be a derivative of the following class:
-
-.. autoclass:: thcolor.Reference
-	:members: _color, functions, colors, default
-
-Builtin references
-------------------
-
-The following references are defined:
-
-.. autoclass:: thcolor.CSS1Reference
-
-.. autoclass:: thcolor.CSS2Reference
-
-.. autoclass:: thcolor.CSS3Reference
-
-.. autoclass:: thcolor.CSS4Reference
-
-.. autoclass:: thcolor.DefaultReference
diff --git a/docs/index.rst b/docs/index.rst
index 33e175d..50b5c57 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -5,26 +5,17 @@ This module is a color management module made by `Thomas Touhey`_ (``th``
 is for ``touhey``) for the `textoutpc`_ project, a BBCode to HTML translation
 module. It provides the following features:
 
-- color management and conversions between formats (RGB, HSL, HWB, NCol, …).
-- text-to-color using close-to-CSS format.
-
-To install the module, use pip:
-
-.. code-block:: bash
-
-	$ pip install thcolor
+ * Color management and conversions between formats (RGB, HSL, HWB, NCol, …).
+ * Text-to-color using a format close to CSS.
 
 For more information and links, consult `the official website`_.
 
-Table of contents
------------------
-
 .. toctree::
 	:maxdepth: 2
 
-	angles
-	colors
-	expressions
+	onboarding
+	discuss
+	api
 
 .. _Thomas Touhey: https://thomas.touhey.fr/
 .. _textoutpc: https://textout.touhey.pro/
diff --git a/docs/onboarding.rst b/docs/onboarding.rst
new file mode 100644
index 0000000..412df44
--- /dev/null
+++ b/docs/onboarding.rst
@@ -0,0 +1,12 @@
+Onboarding
+==========
+
+You're a new user trying to figure out what you can and cannot do with
+thcolor, and you're willing to experiment? You're at the right place!
+In this section, you will be able to install, run and start tweaking
+thcolor to better suit your needs.
+
+.. toctree::
+
+	onboarding/installing
+	onboarding/tweaking
diff --git a/docs/onboarding/installing.rst b/docs/onboarding/installing.rst
new file mode 100644
index 0000000..4fee3ca
--- /dev/null
+++ b/docs/onboarding/installing.rst
@@ -0,0 +1,35 @@
+Installing thcolor
+==================
+
+In order to run and tweak thcolor, you must first install it; this section
+will cover the need.
+
+Dependencies
+------------
+
+thcolor dependencies are pure Python dependencies, automatically installed
+when using a package manager such as pip:
+
+ * regex_, used for parsing color expressions.
+
+Installing thcolor using pip
+----------------------------
+
+To install thcolor, you can use pip with the following command:
+
+.. code-block:: sh
+
+	python -m pip install thcolor
+
+Some notes on this command:
+
+ * On most Linux distributions, you can directly call ``pip`` (or ``pip3``
+   on those where Python 2.x is still the default); I personnally prefer
+   to call it through Python as a module.
+ * On Linux and other UNIX-like distributions where Python 2.x is still the
+   default, when Python 3.x is installed, you must usually call it using
+   ``python3`` instead of ``python``.
+ * On Microsoft Windows, the Python executable, when added to the PATH,
+   goes by the name ``py`` instead of ``python``.
+
+.. _regex: https://pypi.org/project/regex/
diff --git a/docs/onboarding/tweaking.rst b/docs/onboarding/tweaking.rst
new file mode 100644
index 0000000..9ad9ab2
--- /dev/null
+++ b/docs/onboarding/tweaking.rst
@@ -0,0 +1,16 @@
+Tweaking thcolor
+================
+
+In order to start tweaking thcolor using Python instead of the CLI, you
+can import utilities from the module. The minimal code for running the
+server is the following:
+
+.. code-block:: python
+
+	from thcolor import Color
+
+	color = Color.from_text('darker(#123456 10%)')
+	print(color)
+
+For more information, please consult the discussion topics and API reference
+on the current documentation.
diff --git a/setup.cfg b/setup.cfg
index 7ff488f..af49058 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -36,7 +36,7 @@ source-dir = docs
 universal = True
 
 [flake8]
-ignore = F401, F403, E128, E131, E241, E261, E265, E271, W191
+ignore = F401, F403, E126, E127, E128, E131, E241, E261, E265, E271, W191
 exclude = .git, __pycache__, build, dist, docs/conf.py, test.py, test
 
 [tool:pytest]
diff --git a/setup.py b/setup.py
index 6bcf1c6..7776190 100755
--- a/setup.py
+++ b/setup.py
@@ -1,8 +1,8 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
-# This file is part of the thcolor Python 3.x module, which is MIT-licensed.
-#******************************************************************************
+# This file is part of the thcolor Python module, which is MIT-licensed.
+#**************************************************************************
 """ Setup script for the thcolor Python package and script. """
 
 from setuptools import setup as _setup
@@ -12,7 +12,7 @@ kwargs = {}
 try:
 	from sphinx.setup_command import BuildDoc as _BuildDoc
 	kwargs['cmdclass'] = {'build_sphinx': _BuildDoc}
-except:
+except ImportError:
 	pass
 
 # Actually, most of the project's data is read from the `setup.cfg` file.
diff --git a/thcolor/__init__.py b/thcolor/__init__.py
index 22c8a7e..116a77f 100755
--- a/thcolor/__init__.py
+++ b/thcolor/__init__.py
@@ -1,24 +1,17 @@
 #!/usr/bin/env python3
-#******************************************************************************
-# Copyright (C) 2018 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+#**************************************************************************
+# Copyright (C) 2018-2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
+#**************************************************************************
 """ HTML/CSS-like color parsing, mainly for the `[color]` tag.
 	Defines the `get_color()` function which returns an rgba value.
 
 	The functions in this module do not aim at being totally compliant with
-	the W3C standards, although it is inspired from it.
-"""
+	the W3C standards, although it is inspired from it. """
 
-from ._color import Color
-from ._ref import Reference
-from ._angle import Angle
-
-from ._exc import ColorExpressionDecodingError
-
-__all__ = ["version", "Color", "Reference", "Angle",
-	"ColorExpressionDecodingError"]
-
-version = "0.3.1"
+from .version import *
+from .errors import *
+from .colors import *
+from .angles import *
 
 # End of file.
diff --git a/thcolor/_angle.py b/thcolor/_angle.py
deleted file mode 100755
index ac3198d..0000000
--- a/thcolor/_angle.py
+++ /dev/null
@@ -1,295 +0,0 @@
-#!/usr/bin/env python3
-#******************************************************************************
-# Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
-# This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
-""" Angle management. """
-
-from math import pi as _pi
-from enum import Enum as _Enum
-
-__all__ = ["Angle"]
-
-def _deg(name, value):
-	value = float(value)
-	return value # % 360.0
-
-def _grad(name, value):
-	value = float(value)
-	return value # % 400.0
-
-def _rad(name, value):
-	value = float(value)
-	return value # % (2 * _pi)
-
-def _turn(name, value):
-	value = float(value)
-	return value # % 1
-
-# ---
-# Angle definition.
-# ---
-
-class Angle:
-	""" Class representing an angle within thcolor, used for some color
-		representations (most notably hue). Its constructor depends on the
-		first given argument, which represents the angle type as one of the
-		:class:`Angle.Type` constants.
-
-		.. function:: Angle(Angle.Type.DEG, degrees)
-
-			Create an angle with a value in degrees (canonical values are
-			between 0 and 360 excluded). For example, to create a 270° angle:
-
-			.. code-block:: python
-
-				angle = Angle(Angle.Type.DEG, 270)
-
-		.. function:: Angle(Angle.Type.GRAD, gradiants)
-
-			Create an angle with a value in gradiants (canonical values are
-			between 0 and 400 excluded). For example, to create a 565.5
-			gradiants angle:
-
-			.. code-block:: python
-
-				angle = Angle(Angle.Type.GRAD, 565.5)
-
-		.. function:: Angle(Angle.Type.RAD, radiants)
-
-			Create an angle with a value in radiants (canonical values are
-			between 0 and 2π excluded). For example, to create a π
-			radiants angle:
-
-			.. code-block:: python
-
-				from math import pi
-				angle = Angle(Angle.Type.RAD, pi)
-
-		.. function:: Angle(Angle.Type.TURN, turns)
-
-			Create an angle with a value in turns (canonical values are
-			between 0 and 1 excluded). For example, to create a 3.5 turns
-			angle:
-
-			.. code-block:: python
-
-				angle = Angle(Angle.Type.TURN, 3.5) """
-
-	# Properties to work with:
-	#
-	# `_type`: the type as one of the `Angle.Type` constants.
-	# `_value`: the angle value.
-
-	class Type(_Enum):
-		""" Class representing the type of an angle, its unit really.
-			The following types are available:
-
-			.. data:: INVALID
-
-				An invalid angle, for internal processing.
-
-			.. data:: DEG
-
-				An angle in degrees. A full circle is represented by
-				360 degrees.
-
-			.. data:: GRAD
-
-				An angle in gradiants. A full circle is represented by
-				400 gradiants.
-
-			.. data:: RAD
-
-				An angle in radiants. A full circle is represented by
-				2π radiants.
-
-			.. data:: TURN
-
-				An angle in turns. A full circle is represented by 1 turn. """
-
-		INVALID = 0
-		DEG     = 1
-		GRAD    = 2
-		RAD     = 3
-		TURN    = 4
-
-	def __init__(self, *args, **kwargs):
-		self._type = Angle.Type.INVALID
-		self.set(*args, **kwargs)
-
-	def __eq__(self, other):
-		if not isinstance(other, Angle):
-			return super().__eq__(other)
-
-		if   self._type == Angle.Type.INVALID:
-			return other.type == Angle.Type.INVALID
-		elif self._type == Angle.Type.DEG:
-			return other.degrees == self._value
-		elif self._type == Angle.Type.GRAD:
-			return other.gradiants == self._value
-		elif self._type == Angle.Type.RAD:
-			return other.radiants == self._value
-		elif self._type == Angle.Type.TURN:
-			return other.turns == self._value
-
-		return False
-
-	def __repr__(self):
-		args = (('type', f'{self.__class__.__name__}.{str(self._type)}'),)
-		if self._type in (Angle.Type.DEG, Angle.Type.GRAD, Angle.Type.RAD,
-			Angle.Type.TURN):
-			args += (('value', repr(self._value)),)
-
-		argtext = ', '.join(f'{key} = {value}' for key, value in args)
-		return f"{self.__class__.__name__}({argtext})"
-
-	# ---
-	# Management methods.
-	# ---
-
-	def set(self, *args, **kwargs):
-		""" Set the angle. """
-
-		args = list(args)
-
-		def _decode_varargs(*keys):
-			# Check for each key.
-
-			results = ()
-
-			for names, convert_func, *value in keys:
-				for name in names:
-					if name in kwargs:
-						if args:
-							raise TypeError(f"{self.__class__.__name__}() " \
-								f"got multiple values for argument {name}")
-
-						raw_result = kwargs.pop(name)
-						break
-				else:
-					name = names[0]
-					if args:
-						raw_result = args.pop(0)
-					elif value:
-						raw_result = value[0] if len(value) == 1 else value
-					else:
-						raise TypeError(f"{self.__class__.__name__}() " \
-							"missing a required positional argument: " \
-							f"{name}")
-
-				result = convert_func(name, raw_result)
-				results += (result,)
-
-			# Check for keyword arguments for which keys are not in the set.
-
-			if kwargs:
-				raise TypeError(f"{next(iter(kwargs.keys()))} is an invalid " \
-					f"keyword argument for type {type}")
-
-			return results
-
-		# ---
-		# Main function body.
-		# ---
-
-		# Check for the type.
-
-		if args:
-			try:
-				type = kwargs.pop('type')
-			except:
-				type = args.pop(0)
-			else:
-				if isinstance(args[0], Color.Type):
-					raise TypeError(f"{self.__class__.__name__}() got " \
-						"multiple values for argument 'type'")
-		else:
-			try:
-				type = kwargs.pop('type')
-			except:
-				type = self._type
-				if type == Angle.Type.INVALID:
-					raise TypeError(f"{self.__class__.__name__}() missing " \
-						"required argument: 'type'")
-
-		try:
-			type = Angle.Type(type)
-		except:
-			type = Angle.Type.DEG
-
-		# Initialize the properties.
-
-		if   type == Angle.Type.DEG:
-			self._value, = _decode_varargs(\
-				(('value', 'angle', 'degrees'), _deg))
-		elif type == Angle.Type.GRAD:
-			self._value, = _decode_varargs(\
-				(('value', 'angle', 'gradiants'), _grad))
-		elif type == Angle.Type.RAD:
-			self._value, = _decode_varargs(\
-				(('value', 'angle', 'radiants'), _rad))
-		elif type == Angle.Type.TURN:
-			self._value, = _decode_varargs(\
-				(('value', 'angle', 'turns'), _turn))
-		else:
-			raise ValueError(f"invalid color type: {type}")
-
-		# Once the arguments have been tested to be valid, we can set the
-		# type.
-
-		self._type = type
-
-	# ---
-	# Properties.
-	# ---
-
-	@property
-	def type(self):
-		""" The read-only angle type as one of the :class:`Angle.Type`
-			constants. """
-
-		return self._type
-
-	@property
-	def degrees(self):
-		""" The read-only angle value in degrees. If the angle isn't in degrees
-			already, it will be converted automatically. """
-
-		if self._type == Angle.Type.DEG:
-			return self._value
-		return self.turns * 360
-
-	@property
-	def gradiants(self):
-		""" The read-only angle value in gradiants. If the angle isn't in
-			gradiants already, it will be converted automatically. """
-
-		if self._type == Angle.Type.GRAD:
-			return self._value
-		return self.turns * 400
-
-	@property
-	def radiants(self):
-		""" The read-only angle value in radiants. If the angle isn't in
-			radiants already, it will be converted automatically. """
-
-		if self._type == Angle.Type.RAD:
-			return self._value
-		return self.turns * (2 * _pi)
-
-	@property
-	def turns(self):
-		""" The read-only angle value in turns. If the angle isn't in
-			turns already, it will be converted automatically. """
-
-		if   self._type == Angle.Type.DEG:
-			return self._value / 360
-		elif self._type == Angle.Type.GRAD:
-			return self._value / 400
-		elif self._type == Angle.Type.RAD:
-			return self._value / (2 * _pi)
-		elif self._type == Angle.Type.TURN:
-			return self._value
-
-# End of file.
diff --git a/thcolor/_color.py b/thcolor/_color.py
index 1bc8f6e..c877197 100755
--- a/thcolor/_color.py
+++ b/thcolor/_color.py
@@ -1,14 +1,26 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
+#**************************************************************************
 """ HTML/CSS like color parsing, mainly for the `[color]` tag.
 	Defines the `get_color()` function which returns an rgba value. """
 
+from copy import copy as _copy
 from enum import Enum as _Enum
+from collections.abc import Sequence as _Sequence
 from warnings import warn as _warn
 
+from .angles import Angle as _Angle
+from .errors import (
+	ColorExpressionDecodingError as _ColorExpressionDecodingError,
+	NotEnoughArgumentsError as _NotEnoughArgumentsError,
+	TooManyArgumentsError as _TooManyArgumentsError,
+	InvalidArgumentTypeError as _InvalidArgumentTypeError,
+	InvalidArgumentValueError as _InvalidArgumentValueError)
+
+__all__ = ["Color"]
+
 _gg_no_re = False
 
 try:
@@ -18,47 +30,32 @@ except ImportError:
 		RuntimeWarning)
 	_gg_no_re = True
 
-from ._ref import Reference as _Reference
-from ._angle import Angle as _Angle
-from ._sys import (hls_to_rgb as _hls_to_rgb, rgb_to_hls as _rgb_to_hls,
-	rgb_to_hwb as _rgb_to_hwb, hwb_to_rgb as _hwb_to_rgb,
-	rgb_to_cmyk as _rgb_to_cmyk, cmyk_to_rgb as _cmyk_to_rgb,
-	lab_to_rgb as _lab_to_rgb, rgb_to_lab as _rgb_to_lab,
-	lab_to_lch as _lab_to_lch, lch_to_lab as _lch_to_lab,
-	netscape_color as _netscape_color)
-from ._exc import (\
-	ColorExpressionDecodingError as _ColorExpressionDecodingError,
-	NotEnoughArgumentsError as _NotEnoughArgumentsError,
-	TooManyArgumentsError as _TooManyArgumentsError,
-	InvalidArgumentTypeError as _InvalidArgumentTypeError,
-	InvalidArgumentValueError as _InvalidArgumentValueError)
-
-__all__ = ["Color"]
-
 # ---
 # Decoding utilities.
 # ---
 
 _color_pattern = None
 
+
 def _get_color_pattern():
 	global _color_pattern
 
 	if _color_pattern is None:
 		if _gg_no_re:
-			raise ImportError("text parsing is disabled until you install " \
+			raise ImportError("text parsing is disabled until you install "
 				"the 'regex' module, e.g. via `pip install regex`.")
 
 		_color_pattern = _re.compile(r"""
 			(
 				((?P<agl_val>-? ([0-9]+\.?|[0-9]*\.[0-9]+)) \s*
-				 (?P<agl_typ>deg|grad|rad|turn))
-			  | ((?P<per>[0-9]+(\.[0-9]*)? | \.[0-9]+) \s* \%)
-			  |  (?P<num>[0-9]+(\.[0-9]*)? | \.[0-9]+)
-			  |  (?P<ncol>[RYGCBM] [0-9]{0,2} (\.[0-9]*)?)
-			  |  (\# (?P<hex>[0-9a-f]{3} | [0-9a-f]{4} | [0-9a-f]{6} | [0-9a-f]{8}))
-			  |  ((?P<name>[a-z]([a-z0-9\s_-]*[a-z0-9_-])?)
-				  ( \s* \( \s* (?P<arg> (?0)? ) \s* \) )?)
+					(?P<agl_typ>deg|grad|rad|turn))
+			| ((?P<per>[0-9]+(\.[0-9]*)? | \.[0-9]+) \s* \%)
+			|  (?P<num>[0-9]+(\.[0-9]*)? | \.[0-9]+)
+			|  (?P<ncol>[RYGCBM] [0-9]{0,2} (\.[0-9]*)?)
+			|  (\# (?P<hex>[0-9a-f]{3} | [0-9a-f]{4}
+				| [0-9a-f]{6} | [0-9a-f]{8}))
+			|  ((?P<name>[a-z]([a-z0-9\s_-]*[a-z0-9_-])?)
+				( \s* \( \s* (?P<arg> (?0)? ) \s* \) )?)
 			)
 
 			\s* ((?P<sep>[,/\s])+ \s* (?P<nextargs> (?0))?)?
@@ -70,25 +67,28 @@ def _get_color_pattern():
 # Color initialization varargs utilities.
 # ---
 
+
 def _color_profile(name, value):
 	try:
 		value = Color.Profile.from_value(value)
 	except (TypeError, ValueError):
-		raise ValueError(f"{name} is not a valid color profile " \
+		raise ValueError(f"{name} is not a valid color profile "
 			f"(got {repr(value)}).")
 
 	return value
 
+
 def _byte(name, value):
 	try:
 		assert value == int(value)
 		assert 0 <= value < 256
 	except (AssertionError, TypeError, ValueError):
-		raise ValueError(f"{name} should be a byte between 0 and 255") \
-			from None
+		raise ValueError(f"{name} should be a byte between 0 "
+			"and 255") from None
 
 	return value
 
+
 def _signed(name, value):
 	try:
 		value = float(value)
@@ -97,6 +97,7 @@ def _signed(name, value):
 
 	return round(value, 4)
 
+
 def _unsigned(name, value):
 	try:
 		value = float(value)
@@ -106,41 +107,47 @@ def _unsigned(name, value):
 
 	return round(value, 4)
 
+
 def _unrestricted_percentage(name, value):
 	try:
 		value = float(value)
 		assert 0.0 <= value
 	except (AssertionError, TypeError, ValueError):
-		raise ValueError(f"{name} should be a proportion starting from 0") \
-			from None
+		raise ValueError(f"{name} should be a proportion starting "
+			"from 0") from None
 
 	return round(value, 4)
 
+
 def _percentage(name, value):
 	try:
 		value = float(value)
 		assert 0.0 <= value <= 1.0
 	except (AssertionError, TypeError, ValueError):
-		raise ValueError(f"{name} should be a proportion between 0 " \
+		raise ValueError(f"{name} should be a proportion between 0 "
 			"and 1.0") from None
 
 	return round(value, 4)
 
+
 def _hue(name, value):
 	if isinstance(value, _Angle):
 		pass
 	else:
 		try:
 			value = _Angle(value)
-		except:
-			raise ValueError(f"{name} should be an Angle instance")
+		except ValueError:
+			raise ValueError(f"{name} should be an Angle instance") \
+				from None
 
 	return value
 
+
 # ---
 # Color class definition.
 # ---
 
+
 class Color:
 	""" Class representing a color within thcolor. Its constructor depends
 		on the first given argument, which represents the color type as one
@@ -148,43 +155,46 @@ class Color:
 
 		.. function:: Color(Color.Type.RGB, red, green, blue, alpha = 1.0)
 
-			Create a color using its red, green and blue components. Each is
-			expressed as a byte value, from 0 (dark) to 255 (light).
+			Create a color using its red, green and blue components. Each
+			is expressed as a byte value, from 0 (dark) to 255 (light).
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
-		.. function:: Color(Color.Type.RGB, profile, red, green, blue, """ \
-			"""alpha = 1.0)
+		.. function:: Color(Color.Type.RGB, profile, red, green, """ \
+			"""blue, alpha = 1.0)
 
-			Create a color using its profile, red, green and blue component.
-			Each is expressed as a byte value, from 0 (dark) to 255 (light).
+			Create a color using its profile, red, green and blue
+			component. Each is expressed as a byte value, from 0 (dark) to
+			255 (light).
 
 			The profile is one of the :class:`thcolor.Color.Profile`
 			constants, and represents the RGB profile.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
-		.. function:: Color(Color.Type.HSL, hue, saturation, lightness, """ \
-			"""alpha = 1.0)
+		.. function:: Color(Color.Type.HSL, hue, saturation, """ \
+			"""lightness, alpha = 1.0)
 
-			Create a color using its hue, saturation and lightness components.
-			The hue is represented by an :class:`Angle` object, and the
-			saturation and lightness are values going from 0.0 to 1.0.
+			Create a color using its hue, saturation and lightness
+			components. The hue is represented by an :class:`Angle` object,
+			and the saturation and lightness are values going from 0.0 to
+			1.0.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
-		.. function:: Color(Color.Type.HWB, hue, whiteness, blackness, """ \
-			"""alpha = 1.0)
+		.. function:: Color(Color.Type.HWB, hue, whiteness, """ \
+			"""blackness, alpha = 1.0)
 
-			Create a color using its hue, whiteness and blackness components.
-			The hue is represented by an :class:`Angle` object, and the
-			whiteness and lightness are values going from 0.0 to 1.0.
+			Create a color using its hue, whiteness and blackness
+			components. The hue is represented by an :class:`Angle` object,
+			and the whiteness and lightness are values going from 0.0 to
+			1.0.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
 		.. function:: Color(Color.Type.CMYK, cyan, magenta, yellow, """ \
 			"""black, alpha = 1.0)
@@ -192,35 +202,35 @@ class Color:
 			Create a color using its cyan, magenta, yellow and blackness
 			components, which are all values going from 0.0 to 1.0.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
 		.. function:: Color(Color.Type.LAB, lightness, a, b, alpha = 1.0)
 
-			Create a color using its CIE Lightness (similar to the lightness
-			in the HSL representation) and the A and B axises in the Lab
-			colorspace, represented by signed numbers.
+			Create a color using its CIE Lightness (similar to the
+			lightness in the HSL representation) and the A and B axises in
+			the Lab colorspace, represented by signed numbers.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
 		.. function:: Color(Color.Type.LCH, lightness, chroma, hue, """ \
 			"""alpha = 1.0)
 
-			Create a color using its CIE Lightness (similar to the lightness
-			in the HSL representation), its chroma (as a positive number
-			theoretically unbounded) and its hue.
+			Create a color using its CIE Lightness (similar to the
+			lightness in the HSL representation), its chroma (as a positive
+			number theoretically unbounded) and its hue.
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components.
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components.
 
 		.. function:: Color(Color.Type.XYZ, x, y, z, alpha = 1.0)
 
 			Create a color using its CIE XYZ components (as numbers between
 			0 and 1).
 
-			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can be
-			appended to the base components. """
+			An alpha value going from 0.0 (invisible) to 1.0 (opaque) can
+			be appended to the base components. """
 
 	class Type(_Enum):
 		""" Class representing the type of a color, or how it is expressed.
@@ -237,18 +247,18 @@ class Color:
 
 			.. data:: HSL
 
-				A color expressed through its HSL components: hue, saturation
-				and lightness.
+				A color expressed through its HSL components: hue,
+				saturation and lightness.
 
 			.. data:: HWB
 
-				A color expressed through its HWB components: hue, whiteness
-				and blackness.
+				A color expressed through its HWB components: hue,
+				whiteness and blackness.
 
 			.. data:: CMYK
 
-				A color expressed through its CMYK components: cyan, magenta,
-				yellow and black.
+				A color expressed through its CMYK components: cyan,
+				magenta, yellow and black.
 
 			.. data:: LAB
 
@@ -270,18 +280,17 @@ class Color:
 		# going up to 65535, just in case.
 
 		INVALID = 65600
-
-		RGB     = 65601
-		HSL     = 65602
-		HWB     = 65603
-		CMYK    = 65604
-		LAB     = 65605
-		LCH     = 65606
-		XYZ     = 65607
+		RGB = 65601
+		HSL = 65602
+		HWB = 65603
+		CMYK = 65604
+		LAB = 65605
+		LCH = 65606
+		XYZ = 65607
 
 	class Profile(_Enum):
-		""" Class representing the profile of a color, or how it is expressed.
-			The following profiles are available:
+		""" Class representing the profile of a color, or how it is
+			expressed. The following profiles are available:
 
 			.. data:: SRGB
 
@@ -310,26 +319,26 @@ class Color:
 				Level 4
 				<https://drafts.csswg.org/css-color/#valdef-color-rec2020>`_. """
 
-		SRGB        = 65700
-		IMAGE_P3    = 65701
-		A98RGB      = 65702
+		SRGB = 65700
+		IMAGE_P3 = 65701
+		A98RGB = 65702
 		PROPHOTORGB = 65703
-		REC2020     = 65704
+		REC2020 = 65704
 
 		def from_value(value):
 			_profiles = {
-				'srgb':        'SRGB',
-				'imagep3':     'IMAGE_P3',
-				'a98rgb':      'A98RGB',
+				'srgb': 'SRGB',
+				'imagep3': 'IMAGE_P3',
+				'a98rgb': 'A98RGB',
 				'prophotorgb': 'PROPHOTORGB',
-				'rec2020':     'REC2020'}
+				'rec2020': 'REC2020'}
 
 			if type(value) == str:
-				newval = ''.join(c for c in value.casefold() if c in \
-					'0123456789abcdefghijklmnopqrstuvwxyz')
+				newval = ''.join(c for c in value.casefold() if c
+					in '0123456789abcdefghijklmnopqrstuvwxyz')
 				try:
 					value = _profiles[newval]
-				except:
+				except KeyError:
 					pass
 
 				return getattr(Color.Profile, value)
@@ -370,7 +379,7 @@ class Color:
 
 	def __init__(self, *args, **kwargs):
 		self._type = Color.Type.INVALID
-		self.set(*args, **kwargs)
+		self._set(*args, **kwargs)
 
 	def __repr__(self):
 		args = (('type', f'{self.__class__.__name__}.{str(self._type)}'),)
@@ -380,14 +389,17 @@ class Color:
 				('red', repr(self._r)), ('green', repr(self._g)),
 				('blue', repr(self._b)))
 		elif self._type == Color.Type.HSL:
-			args += (('hue', repr(self._hue)), ('saturation', repr(self._sat)),
+			args += (('hue', repr(self._hue)),
+				('saturation', repr(self._sat)),
 				('lightness', repr(self._lgt)))
 		elif self._type == Color.Type.HWB:
-			args += (('hue', repr(self._hue)), ('whiteness', repr(self._wht)),
+			args += (('hue', repr(self._hue)),
+				('whiteness', repr(self._wht)),
 				('blackness', repr(self._blk)))
 		elif self._type == Color.Type.CMYK:
-			args += (('cyan', repr(self._cy)), ('magenta', repr(self._ma)),
-				('yellow', repr(self._ye)), ('black', repr(self._bl)))
+			args += (('cyan', repr(self._cy)),
+				('magenta', repr(self._ma)), ('yellow', repr(self._ye)),
+				('black', repr(self._bl)))
 		elif self._type == Color.Type.LAB:
 			args += (('lightness', repr(self._lgt)), ('a', repr(self._a)),
 				('b', repr(self._b)))
@@ -428,7 +440,13 @@ class Color:
 	# Management methods.
 	# ---
 
-	def set(self, *args, **kwargs):
+	def _setalpha(self, alpha):
+		""" Internal method for setting the alpha value. """
+
+		alpha = _percentage('alpha', alpha)
+		self._alpha = alpha
+
+	def _set(self, *args, **kwargs):
 		""" Set the color using its constructor arguments and keyword
 			arguments. """
 
@@ -460,7 +478,7 @@ class Color:
 				for name in names:
 					if name in kwargs:
 						if value is _UNDEFINED and args:
-							raise TypeError(f"{self.__class__.__name__}() " \
+							raise TypeError(f"{self.__class__.__name__}() "
 								f"got multiple values for argument {name}")
 
 						raw_result = kwargs.pop(name)
@@ -472,8 +490,8 @@ class Color:
 					elif args:
 						raw_result = args.pop(0)
 					else:
-						raise TypeError(f"{self.__class__.__name__}() " \
-							"missing a required positional argument: " \
+						raise TypeError(f"{self.__class__.__name__}() "
+							"missing a required positional argument: "
 							f"{name}")
 
 				result = convert_func(name, raw_result)
@@ -484,8 +502,8 @@ class Color:
 			# Check for keyword arguments for which keys are not in the set.
 
 			if kwargs:
-				raise TypeError(f"{next(iter(kwargs.keys()))} is an invalid " \
-					f"keyword argument for type {type}")
+				raise TypeError(f"{next(iter(kwargs.keys()))} is an "
+					f"invalid keyword argument for type {type}")
 
 			return results
 
@@ -498,74 +516,75 @@ class Color:
 		if args:
 			try:
 				type = kwargs.pop('type')
-			except:
+			except KeyError:
 				type = args.pop(0)
 			else:
 				if isinstance(args[0], Color.Type):
-					raise TypeError(f"{self.__class__.__name__}() got " \
+					raise TypeError(f"{self.__class__.__name__}() got "
 						"multiple values for argument 'type'")
 		else:
 			try:
 				type = kwargs.pop('type')
-			except:
+			except KeyError:
 				type = self._type
 				if type == Color.Type.INVALID:
-					raise TypeError(f"{self.__class__.__name__}() missing " \
+					raise TypeError(f"{self.__class__.__name__}() missing "
 						"required argument: 'type'")
 
 		try:
 			type = Color.Type(type)
-		except:
+		except ValueError:
 			type = Color.Type.RGB
 
 		# Initialize the properties.
 
 		if   type == Color.Type.RGB:
 			self._profile, self._r, self._g, self._b, self._alpha = \
-				_decode_varargs(\
-				(('profile', 'p'), _color_profile, 'srgb'),
-				(('red', 'r'),     _byte),
-				(('green', 'g'),   _byte),
-				(('blue', 'b'),    _byte),
-				(('alpha', 'a'),   _percentage, 1.0))
+				_decode_varargs(
+					(('profile', 'p'), _color_profile, 'srgb'),
+					(('red', 'r'),     _byte),
+					(('green', 'g'),   _byte),
+					(('blue', 'b'),    _byte),
+					(('alpha', 'a'),   _percentage, 1.0))
 
 			if self._profile != Color.Profile.SRGB:
-				raise NotImplementedError("rgb profile " \
+				raise NotImplementedError("rgb profile "
 					f"{repr(self._profile)} isn't managed yet.")
 		elif type == Color.Type.HSL:
-			self._hue, self._sat, self._lgt, self._alpha = _decode_varargs(\
+			self._hue, self._sat, self._lgt, self._alpha = _decode_varargs(
 				(('hue', 'h'),                       _hue),
 				(('saturation', 'sat', 's'),         _percentage),
 				(('lightness', 'light', 'lig', 'l'), _percentage),
 				(('alpha', 'a'),                     _percentage, 1.0))
 		elif type == Color.Type.HWB:
-			self._hue, self._wht, self._blk, self._alpha = _decode_varargs(\
+			self._hue, self._wht, self._blk, self._alpha = _decode_varargs(
 				(('hue', 'h'),                _hue),
 				(('whiteness', 'white', 'w'), _percentage),
 				(('blackness', 'black', 'b'), _percentage),
 				(('alpha', 'a'),              _percentage, 1.0))
 		elif type == Color.Type.CMYK:
 			self._cy, self._ma, self._ye, self._bl, self._alpha = \
-				_decode_varargs(\
-				(('cyan', 'c'),    _percentage),
-				(('magenta', 'm'), _percentage),
-				(('yellow', 'y'),  _percentage),
-				(('black', 'b'),   _percentage),
-				(('alpha', 'a'),   _percentage, 1.0))
+				_decode_varargs(
+					(('cyan', 'c'),    _percentage),
+					(('magenta', 'm'), _percentage),
+					(('yellow', 'y'),  _percentage),
+					(('black', 'b'),   _percentage),
+					(('alpha', 'a'),   _percentage, 1.0))
 		elif type == Color.Type.LAB:
-			self._lgt, self._a, self._b, self._alpha = _decode_varargs(\
-				(('lightness', 'light', 'lig', 'l'), _unrestricted_percentage),
-				(('a',),                             _signed),
-				(('b',),                             _signed),
-				(('alpha', 'a'),                     _percentage, 1.0))
+			self._lgt, self._a, self._b, self._alpha = _decode_varargs(
+				(('lightness', 'light', 'lig', 'l'),
+					_unrestricted_percentage),
+				(('a',),         _signed),
+				(('b',),         _signed),
+				(('alpha', 'a'), _percentage, 1.0))
 		elif type == Color.Type.LCH:
-			self._lgt, self._chr, self._hue, self._alpha = _decode_varargs(\
+			self._lgt, self._chr, self._hue, self._alpha = _decode_varargs(
 				(('lightness', 'light', 'lig', 'l'), _percentage),
 				(('chroma', 'chr', 'c'),             _unsigned),
 				(('hue', 'h'),                       _hue),
 				(('alpha', 'a'),                     _percentage, 1.0))
 		elif type == Color.Type.XYZ:
-			self._x, self._y, self._z, self._alpha = _decode_varargs(\
+			self._x, self._y, self._z, self._alpha = _decode_varargs(
 				(('x',),         _percentage),
 				(('y',),         _percentage),
 				(('z',),         _percentage),
@@ -593,6 +612,17 @@ class Color:
 	# Conversion methods.
 	# ---
 
+	def with_alpha(self, alpha):
+		""" Get the same color with a different alpha value.
+			For example:
+
+				>>> Color.from_text("#876543").with_alpha(0.2).rgba()
+				... (135, 101, 67, 0.2) """
+
+		color = _copy(self)
+		color._setalpha(alpha)
+		return color
+
 	def rgb(self):
 		""" Get the sRGB (red, green, blue) components of the color.
 			For example:
@@ -614,16 +644,19 @@ class Color:
 		elif self._type == Color.Type.LAB:
 			return _lab_to_rgb(self._lgt, self._a, self._b)
 		elif self._type == Color.Type.LCH:
-			return _lch_to_rgb(self._lgt, self._chr, self._hue)
+			return _lab_to_rgb(_lch_to_lab(self._lgt, self._chr,
+				self._hue))
 
-		raise ValueError(f"color type {self._type} doesn't translate to rgb")
+		raise ValueError(f"color type {self._type} doesn't translate "
+			f"to rgb")
 
 	def hsl(self):
-		""" Get the HSL (hue, saturation, lightness) components of the color.
-			For example:
+		""" Get the HSL (hue, saturation, lightness) components of the
+			color. For example:
 
 				>>> Color.from_text("hsl(90turn 0% 5%)").hls()
-				... (Angle(type = Angle.Type.TURN, value = 90.0), 0.05, 0.0)
+				... (Angle(type = Angle.Type.TURN, value = 90.0), """ \
+					"""0.05, 0.0)
 
 			If the color is not represented as HSL internally, it will be
 			converted. """
@@ -634,14 +667,14 @@ class Color:
 		try:
 			rgb = self.rgb()
 		except ValueError:
-			raise ValueError(f"color type {self._type} doesn't translate " \
+			raise ValueError(f"color type {self._type} doesn't translate "
 				"to hsl") from None
 
 		return _rgb_to_hls(*rgb)
 
 	def hwb(self):
-		""" Get the HWB (hue, whiteness, blackness) components of the color.
-			For example:
+		""" Get the HWB (hue, whiteness, blackness) components of the
+			color. For example:
 
 				>>> Color.from_text("hwb(.7 turn / 5% 10%)").hwb()
 				... (Angle(type = Angle.Type.TURN, value = 0.7), 0.05, 0.1)
@@ -655,7 +688,7 @@ class Color:
 		try:
 			rgb = self.rgb()
 		except ValueError:
-			raise ValueError(f"color type {self._type} doesn't translate " \
+			raise ValueError(f"color type {self._type} doesn't translate "
 				"to hwb") from None
 
 		return _rgb_to_hwb(*rgb)
@@ -676,7 +709,7 @@ class Color:
 		try:
 			rgb = self.rgb()
 		except ValueError:
-			raise ValueError(f"color type {self._type} doesn't translate " \
+			raise ValueError(f"color type {self._type} doesn't translate "
 				"to cmyk") from None
 
 		return _rgb_to_cmyk(*rgb)
@@ -699,7 +732,7 @@ class Color:
 		try:
 			rgb = self.rgb()
 		except ValueError:
-			raise ValueError(f"color type {self._type} doesn't translate " \
+			raise ValueError(f"color type {self._type} doesn't translate "
 				"to lab") from None
 
 		return _rgb_to_lab(*rgb)
@@ -720,7 +753,7 @@ class Color:
 		try:
 			lab = self.lab()
 		except ValueError:
-			raise ValueError(f"color type {self._type} doesn't translate " \
+			raise ValueError(f"color type {self._type} doesn't translate "
 				"to lch") from None
 
 		return _lab_to_lch(*lab)
@@ -741,8 +774,8 @@ class Color:
 		raise NotImplementedError # TODO
 
 	def rgba(self):
-		""" Get the sRGB (red, green, blue) and alpha components of the color.
-			For example:
+		""" Get the sRGB (red, green, blue) and alpha components of the
+			color. For example:
 
 				>>> Color.from_text("#87654321").rgb()
 				... (135, 101, 67, 0.1294)
@@ -756,40 +789,42 @@ class Color:
 		return (r, g, b, alpha)
 
 	def hsla(self):
-		""" Get the HSL (hue, saturation, lightness) and alpha components of
-			the color. For example:
+		""" Get the HSL (hue, saturation, lightness) and alpha components
+			of the color. For example:
 
 				>>> Color.from_text("hsl(90turn 0% 5% .8)").hlsa()
-				... (Angle(type = Angle.Type.TURN, value = 90.0), 0.05, 0.0, 0.8)
+				... (Angle(type = Angle.Type.TURN, value = 90.0), """ \
+					"""0.05, 0.0, 0.8)
 
 			If the color is not represented as HSL internally, it will be
 			converted. """
 
-		h, s, l = self.hsl()
+		hue, saturation, lightness = self.hsl()
 		alpha = self._alpha
 
-		return (h, s, l, alpha)
+		return (hue, saturation, lightness, alpha)
 
 	def hls(self):
 		""" Alias for :meth:`hsl` but reverses the lightness and
 			saturation for commodity. """
 
-		h, s, l = self.hsl()
-		return (h, l, s)
+		hue, saturation, lightness = self.hsl()
+		return (hue, lightness, saturation)
 
 	def hlsa(self):
 		""" Alias for :meth:`hsla` but reverses the lightness and
 			saturation for commodity. """
 
-		h, s, l, a = self.hsla()
-		return (h, l, s, a)
+		hue, saturation, lightness, alpha = self.hsla()
+		return (hue, lightness, saturation, alpha)
 
 	def hwba(self):
 		""" Get the HWB (hue, whiteness, blackness) and alpha components of
 			the color. For example:
 
 				>>> Color.from_text("hwb(.7 turn / 5% 10% .2)").hwba()
-				... (Angle(type = Angle.Type.TURN, value = 0.7), 0.05, 0.1, 0.2)
+				... (Angle(type = Angle.Type.TURN, value = 0.7), """ \
+					"""0.05, 0.1, 0.2)
 
 			If the color is not represented as HSL internally, it will be
 			converted. """
@@ -800,8 +835,8 @@ class Color:
 		return (h, w, b, a)
 
 	def cmyka(self):
-		""" Get the CMYK (cyan, magenta, yellow, black) and alpha components
-			of the color. For example:
+		""" Get the CMYK (cyan, magenta, yellow, black) and alpha
+			components of the color. For example:
 
 				>>> Color.from_text("cmyk(.1 .2 .3 .4 / 10%)").cmyka()
 				... (0.1, 0.2, 0.3, 0.4, 0.1)
@@ -857,7 +892,7 @@ class Color:
 		x, y, z = self.xyz()
 		alpha = self._alpha
 
-		return (x, y, z)
+		return (x, y, z, alpha)
 
 	def css(self):
 		""" Get the CSS color descriptions, with older CSS specifications
@@ -921,14 +956,14 @@ class Color:
 	def from_str(*args, **kwargs):
 		""" Alias for :meth:`from_text()`. """
 
-		return Color.from_text(value)
+		return Color.from_text(*args, **kwargs)
 
 	def from_string(*args, **kwargs):
 		""" Alias for :meth:`from_text()`. """
 
-		return Color.from_text(value)
+		return Color.from_text(*args, **kwargs)
 
-	def from_text(expr, ref = None):
+	def from_text(expr, ref=None):
 		""" Create a color from a string using a :class:`Reference` object.
 			If the ``ref`` argument is ``None``, then the default reference
 			is loaded.
@@ -936,13 +971,14 @@ class Color:
 			An example:
 
 				>>> Color.from_text("#123456")
-				... Color(type = Color.Type.RGB, red = 18, green = 52, """ \
-				""" blue = 86, alpha = 1.0) """
+				... Color(type = Color.Type.RGB, red = 18, """ \
+					"""green = 52, blue = 86, alpha = 1.0) """
 
 		if ref is None:
 			ref = _Reference.default()
 		if not isinstance(ref, _Reference):
-			raise ValueError("ref is expected to be a subclass of Reference")
+			raise ValueError("ref is expected to be a subclass "
+				"of Reference")
 
 		class argument:
 			def __init__(self, column, value):
@@ -950,8 +986,9 @@ class Color:
 				self._value = value
 
 			def __repr__(self):
-				return f"{self.__class__.__name__}(column = {self._column}, " \
-					f"value = {repr(self._value)})"
+				return (f"{self.__class__.__name__}"
+					f"(column = {self._column}, "
+					f"value = {repr(self._value)})")
 
 			@property
 			def column(self):
@@ -965,6 +1002,10 @@ class Color:
 			if not match:
 				return ()
 
+			args = recurse(column + match.start('nextargs'),
+				_get_color_pattern().fullmatch(match['nextargs'] or ""))
+			value = None
+
 			if   match['agl_val'] is not None:
 				# The matched value is an angle.
 
@@ -974,17 +1015,17 @@ class Color:
 					'rad':  _Angle.Type.RAD,
 					'turn': _Angle.Type.TURN}[match['agl_typ']]
 
-				value = _Reference.angle(_Angle(agl_typ,
+				value = _angle(_Angle(agl_typ,
 					float(match['agl_val'])))
 			elif match['per'] is not None:
 				# The matched value is a percentage.
 
 				value = float(match['per'])
-				value = _Reference.percentage(value)
+				value = _percentage(value)
 			elif match['num'] is not None:
 				# The matched value is a number.
 
-				value = _Reference.number(match['num'])
+				value = _number(match['num'])
 			elif match['hex'] is not None:
 				# The matched value is a hex color.
 
@@ -998,7 +1039,7 @@ class Color:
 				b = int(name[4:6], 16)
 				a = int(name[6:8], 16) / 255.0 if len(name) == 8 else 1.0
 
-				value = _Reference.color(Color(Color.Type.RGB, r, g, b, a))
+				value = _color(Color(Color.Type.RGB, r, g, b, a))
 			elif match['arg'] is not None:
 				# The matched value is a function.
 
@@ -1014,36 +1055,37 @@ class Color:
 				try:
 					func = ref.functions[name]
 				except KeyError:
-					raise _ColorExpressionDecodingError("no such function " \
-						f"{repr(name)}", column = column)
+					raise _ColorExpressionDecodingError("no such function "
+						f"{repr(name)}", column=column)
 
 				try:
 					value = func(*map(lambda x: x.value, args))
 				except _NotEnoughArgumentsError as e:
-					raise _ColorExpressionDecodingError("not enough " \
-						f"arguments (expected at least {e.count} arguments)",
-						column = column, func = name)
+					raise _ColorExpressionDecodingError("not enough "
+						f"arguments (expected at least {e.count} "
+						"arguments)",
+						column=column, func=name)
 				except _TooManyArgumentsError as e:
-					raise _ColorExpressionDecodingError("extraneous " \
+					raise _ColorExpressionDecodingError("extraneous "
 						f"argument (expected {e.count} arguments at most)",
-						column = args[e.count].column, func = name)
+						column=args[e.count].column, func=name)
 				except _InvalidArgumentTypeError as e:
-					raise _ColorExpressionDecodingError("type mismatch for " \
-						f"argument {e.index + 1}: expected {e.expected}, " \
-						f"got {e.got}", column = args[e.index].column,
-						func = name)
+					raise _ColorExpressionDecodingError("type mismatch "
+						f"for argument {e.index + 1}: "
+						f"expected {e.expected}, got {e.got}",
+						column=args[e.index].column, func=name)
 				except _InvalidArgumentValueError as e:
-					raise _ColorExpressionDecodingError("erroneous value " \
+					raise _ColorExpressionDecodingError("erroneous value "
 						f"for argument {e.index + 1}: {e.text}",
-						column = args[e.index].column, func = name)
+						column=args[e.index].column, func=name)
 				except NotImplementedError:
 					raise _ColorExpressionDecodingError("not implemented",
-						column = column, func = name)
+						column=column, func=name)
 			else:
 				if match['ncol']:
-					# The match is probably a natural color (ncol), we ought
-					# to parse it and get the following arguments or, if
-					# anything is invalid, to treat it as a color name.
+					# The match is probably a natural color (ncol), we
+					# ought to parse it and get the following arguments or,
+					# if anything is invalid, to treat it as a color name.
 
 					name = match['ncol']
 
@@ -1055,15 +1097,12 @@ class Color:
 					if number >= 0 and number < 100:
 						# Get the following arguments and check.
 
-						args = recurse(column + match.start('nextargs'),
-							_get_color_pattern().fullmatch(match['nextargs'] \
-							or ""))
-
 						try:
 							assert len(args) >= 2
 							w = args[0].value.to_factor()
 							b = args[1].value.to_factor()
-						except:
+						except (AssertionError, TypeError, ValueError,
+							AttributeError):
 							w = 0
 							b = 0
 						else:
@@ -1071,33 +1110,30 @@ class Color:
 
 						# Calculate the color and return the args.
 
+						angle_base = 'RYGCBM'.find(letter) * 60 \
+							+ number / 100 * 60
 						color = Color(Color.Type.HWB,
-							_Angle(_Angle.Type.DEG, 'RYGCBM'.find(letter) \
-								* 60 + number / 100 * 60), w, b)
+							_Angle(_Angle.Type.DEG, angle_base, w, b))
 
-						# And finally, return the args.
+						value = _color(color)
 
-						return (argument(column, _Reference.color(color)),) \
-							+ args
+				if value is None:
+					# The matched value is a named color.
 
-				# The matched value is a named color.
+					name = match['name']
 
-				name = match['name']
+					try:
+						# Get the named color (e.g. 'blue').
 
-				try:
-					# Get the named color (e.g. 'blue').
-
-					value = ref.colors[name]
-					assert value != None
-				except:
-					r, g, b = _netscape_color(name)
-					value = Color(Color.Type.RGB, r, g, b, 1.0)
+						value = ref.colors[name]
+						assert value is not None
+					except AssertionError:
+						r, g, b = _netscape_color(name)
+						value = Color(Color.Type.RGB, r, g, b, 1.0)
 
-				value = _Reference.color(value)
+					value = _color(value)
 
-			return (argument(column, value),) \
-				+ recurse(column + match.start('nextargs'),
-				_get_color_pattern().fullmatch(match['nextargs'] or ""))
+			return ((argument(column, value),) + args)
 
 		# Strip the expression.
 
@@ -1108,9 +1144,10 @@ class Color:
 
 		# Match the expression (and check it as a whole directly).
 
-		match = _get_color_pattern().fullmatch(expr)
+		match = _color_pattern.fullmatch(expr)
 		if match is None:
-			raise _ColorExpressionDecodingError("expression parsing failed")
+			raise _ColorExpressionDecodingError("expression parsing "
+				"failed")
 
 		# Get the result and check its type.
 
@@ -1124,7 +1161,7 @@ class Color:
 			result = ref.colors[result]
 		except AttributeError:
 			raise _ColorExpressionDecodingError("expected a color",
-				column = column)
+				column=column)
 
 		return result
 
diff --git a/thcolor/_ref.py b/thcolor/_ref.py
index 8a39cbb..9c719a8 100755
--- a/thcolor/_ref.py
+++ b/thcolor/_ref.py
@@ -1,12 +1,14 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
+#**************************************************************************
 """ Named color reference, parent class. """
 
-from inspect import (getfullargspec as _getfullargspec,
-	getmembers as _getmembers, ismethod as _ismethod)
+from copy import copy as _copy
+from inspect import (getfullargspec as _getfullargspec, getmro as _getmro,
+	getmembers as _getmembers, ismethod as _ismethod,
+	isfunction as _isfunction)
 from itertools import count as _count
 from warnings import warn as _warn
 
@@ -21,6 +23,7 @@ __all__ = ["Reference"]
 _default_reference = None
 _color_cls = None
 
+
 def _get_color_class():
 	global _color_cls
 
@@ -31,249 +34,63 @@ def _get_color_class():
 	_color_cls = Color
 	return _color_cls
 
-class _type_or:
-	""" A type or another. """
-
-	def __init__(self, type1, type2):
-		self._type1 = type1
-		self._type2 = type2
-
-	@property
-	def type1(self):
-		return self._type1
-
-	@property
-	def type2(self):
-		return self._type2
-
-	def __repr__(self):
-		return f"{repr(self._type1)} | {repr(self._type2)}"
-
-	def __str__(self):
-		return f"{self._type1} or {self._type2}"
-
-	def __or__(self, other):
-		return type_or(self, other)
-
-	def __contains__(self, other):
-		return other in self._type1 or other in self._type2
 
 # ---
 # Main reference definition.
 # ---
 
+
 class Reference:
 	""" Function reference for color parsing and operations. """
 
-	def __init__(self):
-		pass
-
-	# ---
-	# Base type and function definitions for parsing.
-	# ---
-
-	class base_type(type):
-		""" The metaclass for all types used below. """
-
-		def __new__(mcls, name, bases, attrs):
-			return super().__new__(mcls, name, bases, attrs)
-
-		def __init__(self, name, bases, attrs):
-			self.__name = name
-
-		def __contains__(self, other):
-			return self if other == self else None
-
-		def __or__(self, other):
-			return _type_or(self, other)
-
-		def __repr__(self):
-			return f"<class {repr(self.__name)}>"
-
-		def __str__(self):
-			return self.__name
-
-	class number(metaclass = base_type):
-		""" Syntaxical element for expression decoding, representing
-			a number, integer or decimal, positive or negative.
-
-			This element is usually used to represent a byte value,
-			a factor (usually from 0.0 to 1.0), a color or an angle
-			in degrees. """
-
-		def __init__(self, value):
-			if   type(value) == str:
-				self._strvalue = value
-				self._value = float(value)
-			else:
-				self._value = float(value)
-				if self._value == int(self._value):
-					self._strvalue = str(int(self._value))
-				else:
-					self._strvalue = str(value)
-
-		def __str__(self):
-			return self._strvalue
-
-		@property
-		def value(self):
-			return self._value
-
-		def to_byte(self):
-			""" Make a byte (from 0 to 255) out of the number. """
-
-			try:
-				value = int(self._value)
-
-				assert value == self._value
-				assert 0 <= value < 256
-			except:
-				raise ValueError("unsuitable value for byte conversion: " \
-					f"{repr(self._value)}")
-
-			return value
-
-		def to_factor(self, min = 0.0, max = 1.0):
-			""" Make a factor (usually from 0.0 to 1.0) out of the number. """
-
-			if (min is not None and self._value < min) \
-			or (max is not None and self._value > max):
-				if   max is None:
-					msg = f"above {min}"
-				elif min is None:
-					msg = f"under {max}"
-				else:
-					msg = f"between {min} and {max}"
-
-				raise ValueError(f"expected a value {msg}, got {self._value}")
-
-			try:
-				assert 0.0 <= self._value <= 1.0
-			except:
-				raise ValueError("expected a value between 0.0 and 1.0, got " \
-					f"{self._value}")
-
-			return self._value
+	def __getattr__(self, name):
+		def pred(x):
+			return _isfunction(x) | _ismethod(x)
 
-		def to_hue(self):
-			""" Make an angle in degrees out of the number. """
+		for member_name in dir(self):
+			# Check if it's an interesting member.
 
-			return _Angle(_Angle.Type.DEG, self._value)
+			if member_name[:1] == '_':
+				continue
 
-	class percentage(metaclass = base_type):
-		""" Syntaxical element for expression decoding, representing
-			a percentage (number followed by a '%' sign).
+			member = getattr(self, member_name)
+			if not _ismethod(member) and not _isfunction(member):
+				continue
 
-			This element is usually used to represent a factor (usually
-			from 0% to 100%) or anything that can be factored such as a
-			byte value (where 0% represents 0 and 100% represents 255). """
+			# Access the aliases through the mro using self and super.
 
-		def __init__(self, value):
-			self._value = value
+			for obj in (self, super()):
+				# Check the aliases.
 
-			if value < 0:
-				value = 0
-
-			# value can actually be more than 100.
-
-		def __repr__(self):
-			return f"{self._value} %"
-
-		def to_factor(self, min = 0.0, max = 1.0):
-			""" Make a factor (usually from 0.0 to 1.0) out of the number. """
+				try:
+					aliases = getattr(obj, member_name)._ref_aliases
+				except (AttributeError, AssertionError):
+					continue
 
-			value = self._value / 100
-			if (min is not None and value < min) \
-			or (max is not None and value > max):
-				if   max is None:
-					msg = f"above {min * 100}%"
-				elif min is None:
-					msg = f"under {max * 100}%"
-				else:
-					msg = f"between {min * 100}% and {max * 100}%"
+				for alias_name, alias in aliases:
+					if alias_name == name:
+						# XXX: test
+						print(alias(self.number(1), self.number(2),
+							self.number(3)))
+						return alias
 
-				raise ValueError(f"expected a percentage {msg}, " \
-					f"got {self._value}%")
+		# Explore the aliases in a recursive way.
 
+		try:
+			value = super().__getattr__(name)
 			return value
+		except AttributeError:
+			pass
 
-		def to_byte(self):
-			""" Make a byte (from 0 to 255) out of the number. """
-
-			if  self._value < 0:
-				self._value = 0
-			if  self._value > 100:
-				self._value = 100
-
-			return int(min(self._value / 100, 1.0) * 255)
-
-	class angle(metaclass = base_type):
-		""" Syntaxical element for expression decoding, representing
-			an angle (a number followed by an angle unit: degrees, gradiants,
-			radiants or turns). """
-
-		def __init__(self, value):
-			if not isinstance(value, _Angle):
-				raise TypeError("expected an Angle instance")
-
-			self._value = value
-
-		def __repr__(self):
-			return repr(self._value)
-
-		def to_hue(self):
-			""" Get the :class:`thcolor.Angle` object. """
-
-			return self._value
-
-	class color(metaclass = base_type):
-		""" Syntaxical element for expression decoding, representing
-			a color using several methods:
-
-			- a hexadecimal code preceeded by a '#', e.g. "#123ABC".
-			- a natural color (see
-			  `NCol <https://www.w3schools.com/colors/colors_ncol.asp>`_).
-			- a color name as defined by a :class:`Reference`.
-			- a legacy color name using the legacy color algorithm (or
-			  'Netscape' color algorithm). """
-
-		def __init__(self, value):
-			if not isinstance(value, _get_color_class()):
-				raise ValueError("expected a Color instance")
-
-			self._value = value
-
-		def __repr__(self):
-			return repr(self._value)
-
-		def to_color(self):
-			""" Get the :class:`thcolor.Color` object. """
-
-			return self._value
-
-	# ---
-	# Function helper.
-	# ---
-
-	def alias(*names):
-		""" Decorator for aliasing with another name. Defines a lot, you
-			know. """
-
-		def _decorator(func):
-			if not hasattr(func, '_ref_aliases'):
-				func._ref_aliases = ()
-
-			func._ref_aliases += names
-			return func
-
-		return _decorator
+		raise AttributeError(repr(name)) from None
 
 	# ---
 	# Function and named color getters.
 	# ---
 
 	def _get_functions(self):
-		""" Function getter, which can be used as ``.functions[name](args…)``.
+		""" Function getter, which can be used as
+			``.functions[name](args…)``.
 
 			Provides a wrapper to the method which checks the argument
 			types and perform the necessary conversions before passing
@@ -292,42 +109,18 @@ class Reference:
 
 			def __getitem__(self, name):
 				fref = self._fref
-				found = False
 
-				# First, check if the function name is valid and if the
-				# method exists.
+				# Get the method through __getattr__, who will handle the
+				# recursivity through parent classes up to Reference.
 
-				members = dict(_getmembers(fref, predicate = _ismethod))
-				validname = lambda n: type(n) == str and n[0:1] != '_' \
-					and n not in ('functions', 'named', 'default', 'alias')
-
-				if validname(name):
-					try:
-						method = members[name]
-						found = True
-					except (KeyError, AssertionError):
-						pass
-
-				# Then, if we haven't found the method, check the aliases.
-
-				if not found:
-					for member in members.values():
-						try:
-							aliases = member._ref_aliases
-						except (AttributeError, AssertionError):
-							continue
-
-						if name not in aliases:
-							continue
-						method = member
-						found = True
-						break
-
-				# If we still haven't found the method, well… time to raise
-				# the not found exception.
-
-				if not found:
-					raise KeyError(repr(name))
+				def validname(n):
+					return type(n) == str and n[0:1] != '_' and n \
+						not in ('functions', 'named', 'default', 'alias')
+				try:
+					assert validname(name)
+					method = getattr(fref, name)
+				except (AssertionError, AttributeError):
+					raise KeyError(name)
 
 				# Make a function separated from the class, copy the
 				# annotations and add the type check on each argument.
@@ -341,7 +134,7 @@ class Reference:
 						self.__annotations__ = func.__annotations__
 						try:
 							del self.__annotations__['self']
-						except:
+						except AssertionError:
 							pass
 
 						spec = _getfullargspec(func)
@@ -349,7 +142,7 @@ class Reference:
 						def annotate(arg_name):
 							try:
 								return spec.annotations[arg_name]
-							except:
+							except (AttributeError, KeyError, IndexError):
 								return None
 
 						self._args = list(map(annotate, spec.args[1:]))
@@ -387,7 +180,7 @@ class Reference:
 							if Reference.color in exp:
 								try:
 									args[-1] = self._fref.colors[arg]
-								except:
+								except (IndexError, KeyError):
 									pass
 								else:
 									continue
@@ -406,12 +199,12 @@ class Reference:
 			For example, with a classical CSS reference named ``ref``:
 
 				>>> ref.colors['blue']
-				... Color(type = Color.Type.RGB, red = 0, green = 0, """ \
-					"""blue = 255, alpha = 1.0)
+				... Color(type = Color.Type.RGB, red = 0, """ \
+					"""green = 0, blue = 255, alpha = 1.0)
 				>>> ref.colors[thcolor.Reference.color(""" \
 					"""thcolor.Color.from_text('#123456'))]
-				... Color(type = Color.Type.RGB, red = 18, green = 52, """ \
-					"""blue = 86, alpha = 1.0) """
+				... Color(type = Color.Type.RGB, red = 18, """ \
+					"""green = 52, blue = 86, alpha = 1.0) """
 
 		class _ColorGetter:
 			def __init__(self, ref):
@@ -425,7 +218,7 @@ class Reference:
 
 				try:
 					name = str(key)
-				except:
+				except (TypeError, ValueError):
 					raise KeyError(repr(key))
 
 				try:
@@ -433,23 +226,24 @@ class Reference:
 				except KeyError:
 					pass
 				except Exception as e:
-					_warn(RuntimeWarning, f"{self.__class__.__name__} " \
-						f"returned exception {e.__class__.__name__} instead " \
-						f"of KeyError for color name {repr(name)}.")
+					_warn(RuntimeWarning, f"{self.__class__.__name__} "
+						f"returned exception {e.__class__.__name__} "
+						f"instead of KeyError for color name "
+						f"{repr(name)}.")
 					pass
 				else:
 					try:
 						assert isinstance(value, _get_color_class())
 					except AssertionError:
-						_warn(RuntimeWarning, f"{self.__class__.__name__} " \
-							f"returned non-Color value {repr(value)} for " \
+						_warn(RuntimeWarning, f"{self.__class__.__name__} "
+							f"returned non-Color value {repr(value)} for "
 							f"color name {repr(name)}, ignoring.")
 					else:
 						return value
 
 				try:
 					r, g, b = _netscape_color(name)
-				except:
+				except (TypeError, ValueError):
 					pass
 				else:
 					Color = _get_color_class()
diff --git a/thcolor/_sys.py b/thcolor/_sys.py
deleted file mode 100755
index 014270a..0000000
--- a/thcolor/_sys.py
+++ /dev/null
@@ -1,237 +0,0 @@
-#!/usr/bin/env python3
-#******************************************************************************
-# Copyright (C) 2018 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
-# This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
-""" Conversions between color systems. """
-
-from math import (ceil as _ceil, atan2 as _atan2, sqrt as _sqrt, cos as _cos,
-	sin as _sin, pow as _pow)
-
-from ._angle import Angle as _Angle
-
-__all__ = ["hls_to_rgb", "rgb_to_hls", "rgb_to_hwb", "hwb_to_rgb",
-	"cmyk_to_rgb", "rgb_to_cmyk", "lab_to_rgb", "rgb_to_lab",
-	"lch_to_lab", "lab_to_lch", "netscape_color"]
-
-# ---
-# Color systems conversion utilities.
-# ---
-
-def _rgb(r, g, b):
-	return tuple(map(lambda x: int(round(x * 255, 0)), (r, g, b)))
-def _hls(hue, s, l):
-	return _Angle(_Angle.Type.DEG, round(hue, 2)), round(l, 2), round(s, 2)
-
-def _rgb_to_lrgb(r, g, b):
-	def _linearize(val):
-		# Undo gamma encoding.
-
-		val /= 255
-		if val < 0.04045:
-			return val / 12.92
-
-		return _pow((val + 0.055) / 1.055, 2.4)
-
-	return tuple(map(_linearize, (r, g, b)))
-
-def hls_to_rgb(hue, l, s):
-	""" Convert HLS to RGB. """
-
-	if s == 0:
-		# Achromatic color.
-
-		return l, l, l
-
-	def _hue_to_rgb(t1, t2, hue):
-		hue %= 6
-
-		if   hue < 1:
-			return t1 + (t2 - t1) * hue
-		elif hue < 3:
-			return t2
-		elif hue < 4:
-			return t1 + (t2 - t1) * (4 - hue)
-		return t1
-
-	hue = (hue.degrees % 360) / 60
-	if l <= 0.5:
-		t2 = l * (s + 1)
-	else:
-		t2 = l + s - (l * s)
-
-	t1 = l * 2 - t2
-
-	return _rgb(\
-		_hue_to_rgb(t1, t2, hue + 2),
-		_hue_to_rgb(t1, t2, hue),
-		_hue_to_rgb(t1, t2, hue - 2))
-
-def hwb_to_rgb(hue, w, bl):
-	""" Convert HWB to RGB color.
-		https://drafts.csswg.org/css-color/#hwb-to-rgb """
-
-	r, g, b = map(lambda x: x / 255, hls_to_rgb(hue, 0.5, 1.0))
-	if w + bl > 1:
-		w, bl = map(lambda x: x / (w + bl), (w, bl))
-	return _rgb(*map(lambda x: x * (1 - w - bl) + w, (r, g, b)))
-
-def cmyk_to_rgb(c, m, y, k):
-	""" Convert CMYK to RGB. """
-
-	r = 1 - min(1, c * (1 - k) + k)
-	g = 1 - min(1, m * (1 - k) + k)
-	b = 1 - min(1, y * (1 - k) + k)
-
-	return _rgb(r, g, b)
-
-def lab_to_rgb(l, a, b):
-	""" Convert LAB to RGB. """
-
-	# TODO
-	raise NotImplementedError
-
-def rgb_to_lab(r, g, b):
-	""" Convert RGB to LAB. """
-
-	# TODO
-	raise NotImplementedError
-
-def lab_to_lch(l, a, b):
-	""" Convert RGB to LAB. """
-
-	h = _Angle(_Angle.Type.RAD, _atan2(b, a))
-	c = _sqrt(a * a + b * b)
-
-	return (l, c, h)
-
-def lch_to_lab(l, c, h):
-	""" Convert LCH to LAB. """
-
-	a = c * _cos(h.radians)
-	b = c * _sin(h.radians)
-
-	return (l, a, b)
-
-def rgb_to_hls(r, g, b):
-	""" Convert RGB to HLS. """
-
-	r, g, b = map(lambda x: x / 255, (r, g, b))
-
-	min_value = min((r, g, b))
-	max_value = max((r, g, b))
-	chroma = max_value - min_value
-
-	if   chroma == 0:
-		hue = 0
-	elif r == max_value:
-		hue = (g - b) / chroma
-	elif g == max_value:
-		hue = (b - r) / chroma + 2
-	else:
-		hue = (r - g) / chroma + 4
-
-	hue = hue * 60 + (hue < 0) * 360
-	l = (min_value + max_value) / 2
-	if min_value == max_value:
-		s = 0
-	else:
-		s = max_value - min_value
-		if l < 0.5:
-			s /= max_value + min_value
-		else:
-			s /= 2 - max_value - min_value
-
-	return _hls(hue, l, s)
-
-def rgb_to_hwb(r, g, b):
-	""" Convert RGB to HWB. """
-
-	r, g, b = map(lambda x: x / 255, (r, g, b))
-
-	max_value = max((r, g, b))
-	min_value = min((r, g, b))
-	chroma = max_value - min_value
-
-	if   chroma == 0:
-		hue = 0
-	elif r == max_value:
-		hue = (g - b) / chroma
-	elif g == max_value:
-		hue = (b - r) / chroma + 2
-	elif g == max_value:
-		hue = (r - g) / chroma + 4
-
-	hue = (hue % 6) * 360
-	w = min_value
-	b = max_value
-
-	return _Angle(_Angle.Type.DEG, hue), w, b
-
-def rgb_to_cmyk(r, g, b):
-	""" Convert RGB to CMYK. """
-
-	r, g, b = map(lambda x: x / 255, (r, g, b))
-
-	k = 1 - max((r, g, b))
-	if k == 1:
-		c, m, y = 0, 0, 0
-	else:
-		c = (1 - r - k) / (1 - k)
-		m = (1 - g - k) / (1 - k)
-		y = (1 - b - k) / (1 - k)
-
-	return (c, m, y, k)
-
-# ---
-# Other utilities.
-# ---
-
-def netscape_color(name):
-	""" Produce a color from a name (which can be all-text, all-digits or
-		both), using the Netscape behaviour. """
-
-	# Find more about this here: https://stackoverflow.com/a/8333464
-	#
-	# First of all:
-	# - we sanitize our input by replacing invalid characters
-	#   by '0' characters (the 0xFFFF limit is due to how
-	#   UTF-16 was managed at the time).
-	# - we truncate our input to 128 characters.
-
-	name = name.lower()
-	name = ''.join(c if c in '0123456789abcdef' \
-		else ('0', '00')[ord(c) > 0xFFFF] \
-		for c in name[:128])[:128]
-
-	# Then we calculate some values we're going to need.
-	# `iv` is the size of the zone for a member.
-	# `sz` is the size of the digits slice to take in that zone
-	# (max. 8).
-	# `of` is the offset in the zone of the slice to take.
-
-	iv = _ceil(len(name) / 3)
-	of = iv - 8 if iv > 8 else 0
-	sz = iv - of
-
-	# Then we isolate the slices using the values calculated
-	# above. `gr` will be an array of 3 or 4 digit strings
-	# (depending on the number of members).
-
-	gr = list(map(lambda i: name[i * iv + of:i * iv + iv] \
-		.ljust(sz, '0'), range(3)))
-
-	# Check how many digits we can skip at the beginning of
-	# each slice.
-
-	pre = min(map(lambda x: len(x) - len(x.lstrip('0')), gr))
-	pre = min(pre, sz - 2)
-
-	# Then we extract the values.
-
-	it = map(lambda x: int('0' + x[pre:pre + 2], 16), gr)
-	r, g, b = it
-
-	return (r, g, b)
-
-# End of file.
diff --git a/thcolor/angles.py b/thcolor/angles.py
new file mode 100644
index 0000000..8ad8703
--- /dev/null
+++ b/thcolor/angles.py
@@ -0,0 +1,205 @@
+#!/usr/bin/env python3
+#**************************************************************************
+# Copyright (C) 2019-2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+# This file is part of the thcolor project, which is MIT-licensed.
+#**************************************************************************
+""" Angle representation and conversions. """
+
+from math import pi as _pi
+
+__all__ = ['Angle',
+	'DegreesAngle', 'GradiansAngle', 'RadiansAngle', 'TurnsAngle']
+
+class Angle:
+	""" Abstract class representing an angle within thcolor, used for
+		some color representations (most notably hue). """
+
+	__slots__ = ()
+
+	def __init__(self):
+		pass
+
+	def __repr__(self):
+		params = ((key, getattr(self, key)) for key in dir(self)
+			if not key.startswith('_') and not callable(getattr(self, key)))
+		return (f"{self.__class__.__name__}("
+			f"{', '.join(f'{key} = {repr(val)}' for key, val in params)})")
+
+	def asdegrees(self) -> 'DegreesAngle':
+		""" Get the current angle as a degrees angle. """
+
+		try:
+			value = self._value
+			ob = self._bottom
+			ot = self._top
+		except AttributeError:
+			raise NotImplementedError from None
+
+		nb = DegreesAngle._bottom
+		nt = DegreesAngle._top
+
+		return DegreesAngle((value - ob) / (ot - ob) * (nt - nb) + nb)
+
+	def asgradians(self) -> 'GradiansAngle':
+		""" Get the current angle as a gradians angle. """
+
+		try:
+			value = self._value
+			ob = self._bottom
+			ot = self._top
+		except AttributeError:
+			raise NotImplementedError from None
+
+		nb = GradiansAngle._bottom
+		nt = GradiansAngle._top
+
+		return GradiansAngle((value - ob) / (ot - ob) * (nt - nb) + nb)
+
+	def asradians(self) -> 'RadiansAngle':
+		""" Get the current angle as a radians angle. """
+
+		try:
+			value = self._value
+			ob = self._bottom
+			ot = self._top
+		except AttributeError:
+			raise NotImplementedError from None
+
+		nb = RadiansAngle._bottom
+		nt = RadiansAngle._top
+
+		return RadiansAngle((value - ob) / (ot - ob) * (nt - nb) + nb)
+
+	def asturns(self) -> 'TurnsAngle':
+		""" Get the current angle as a turns angle. """
+
+		try:
+			value = self._value
+			ob = self._bottom
+			ot = self._top
+		except AttributeError:
+			raise NotImplementedError from None
+
+		nb = TurnsAngle._bottom
+		nt = TurnsAngle._top
+
+		return TurnsAngle((value - ob) / (ot - ob) * (nt - nb) + nb)
+
+
+class DegreesAngle(Angle):
+	""" An angle expressed in degrees.
+
+		A 270° angle can be created the following way:
+
+		.. code-block:: python
+
+			angle = DegreesAngle(270)
+
+		:param degrees: Degrees; canonical values are between 0 and 360
+		                excluded. """
+
+	__slots__ = ('_value')
+
+	_bottom = 0
+	_top = 360.0
+
+	def __init__(self, degrees: float):
+		self._value = float(degrees) # % 360.0
+
+	@property
+	def degrees(self) -> float:
+		""" Degrees. """
+
+		return self._value
+
+
+class GradiansAngle(Angle):
+	""" An angle expressed in gradians.
+
+		A 565.5 gradians angle can be created the following way:
+
+		.. code-block:: python
+
+			angle = GradiansAngle(565.5)
+
+		:param gradians: Gradians; canonical values are between
+		                  0 and 400.0 excluded."""
+
+	__slots__ = ('_value')
+
+	_bottom = 0
+	_top = 400.0
+
+	def __init__(self, gradians: float):
+		self._value = float(gradians) # % 400.0
+
+	@property
+	def gradians(self) -> float:
+		""" Gradians. """
+
+		return self._value
+
+
+class RadiansAngle(Angle):
+	""" An angle expressed in radians.
+
+		A π radians angle can be created the following way:
+
+		.. code-block:: python
+
+			from math import pi
+			angle = RadiansAngle(pi)
+
+		:param radians: Radians; canonical are between 0 and 2π
+		                 excluded. """
+
+	__slots__ = ('_value')
+
+	_bottom = 0
+	_top = 2 * _pi
+
+	def __init__(self, radians: float):
+		self._value = float(radians) # % (2 * _pi)
+
+	def __repr__(self):
+		r = self.radians / _pi
+		ir = int(r)
+		if r == ir:
+			r = ir
+
+		return f"{self.__class__.__name__}(radians = {f'{r}π' if r else '0'})"
+
+	@property
+	def radians(self) -> float:
+		""" Radians. """
+
+		return self._value
+
+
+class TurnsAngle(Angle):
+	""" An angle expressed in turns.
+
+		A 3.5 turns angle can be created the following way:
+
+		.. code-block:: python
+
+			angle = TurnsAngle(3.5)
+
+		:param turns: Turns; canonical values are between 0 and 1
+		              excluded. """
+
+	__slots__ = ('_value')
+
+	_bottom = 0
+	_top = 1
+
+	def __init__(self, turns: float):
+		self._value = float(turns) # % 1.0
+
+	@property
+	def turns(self) -> float:
+		""" Turns. """
+
+		return self._value
+
+# End of file.
diff --git a/thcolor/builtin/__init__.py b/thcolor/builtin/__init__.py
index c9bc0d2..b9ed556 100755
--- a/thcolor/builtin/__init__.py
+++ b/thcolor/builtin/__init__.py
@@ -1,8 +1,8 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
+#**************************************************************************
 """ Named colors references, using various sources. """
 
 from ._css import (CSS1Reference, CSS2Reference, CSS3Reference,
diff --git a/thcolor/builtin/_css.py b/thcolor/builtin/_css.py
index ac9e434..457d560 100755
--- a/thcolor/builtin/_css.py
+++ b/thcolor/builtin/_css.py
@@ -1,18 +1,22 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
-""" Named colors and function definitions. Color names are case-insensitive.
+#**************************************************************************
+""" Named colors and function definitions. Color names are
+	case-insensitive.
 	Taken from: https://www.w3schools.com/cssref/css_colors.asp """
 
 from .._color import Color as _Color
 from .._ref import Reference as _Reference
 from .._exc import InvalidArgumentValueError as _InvalidArgumentValueError
+from ..syntax import (number as _number, percentage as _percentage,
+	angle as _angle, color as _color, alias as _alias)
 
 __all__ = ["CSS1Reference", "CSS2Reference", "CSS3Reference",
 	"CSS4Reference"]
 
+
 def _rgb(raw):
 	r = int(raw[1:3], 16)
 	g = int(raw[3:5], 16)
@@ -20,373 +24,271 @@ def _rgb(raw):
 
 	return _Color(_Color.Type.RGB, r, g, b)
 
+
 class CSS1Reference(_Reference):
 	""" Named colors from `CSS Level 1 <https://www.w3.org/TR/CSS1/>`_. """
 
-	number = _Reference.number
-	percentage = _Reference.percentage
-	color = _Reference.color
-
-	def __init__(self, *args, **kwargs):
-		super().__init__(*args, **kwargs)
-
-	# ---
-	# Named colors.
-	# ---
-
-	__colors = {
-		'black':   _rgb('#000000'),
-		'silver':  _rgb('#c0c0c0'),
-		'gray':    _rgb('#808080'),
-		'white':   _rgb('#ffffff'),
-
-		'maroon':  _rgb('#800000'),
-		'red':     _rgb('#ff0000'),
-		'purple':  _rgb('#800080'),
-		'fuchsia': _rgb('#ff00ff'),
-		'green':   _rgb('#008000'),
-		'lime':    _rgb('#00ff00'),
-		'olive':   _rgb('#808000'),
-		'yellow':  _rgb('#ffff00'),
-		'navy':    _rgb('#000080'),
-		'blue':    _rgb('#0000ff'),
-		'teal':    _rgb('#008080'),
-		'aqua':    _rgb('#00ffff')}
-
-	def _color(self, name):
-		if name == 'transparent':
-			return _Color(_Color.Type.RGB, 0, 0, 0, 0)
-
-		try:
-			return self.__colors[name]
-		except:
-			return super()._color(name)
+	black = _rgb('#000000')
+	silver = _rgb('#c0c0c0')
+	gray = _rgb('#808080')
+	white = _rgb('#ffffff')
+
+	maroon = _rgb('#800000')
+	red = _rgb('#ff0000')
+	purple = _rgb('#800080')
+	fuchsia = _rgb('#ff00ff')
+	green = _rgb('#008000')
+	lime = _rgb('#00ff00')
+	olive = _rgb('#808000')
+	yellow = _rgb('#ffff00')
+	navy = _rgb('#000080')
+	blue = _rgb('#0000ff')
+	teal = _rgb('#008080')
+	aqua = _rgb('#00ffff')
+
+	transparent = _RGBColor(0, 0, 0, 0)
 
 	# ---
-	# Utilities.
+	# Functions.
 	# ---
 
-	def _rgb(self, rgba, rgb_indexes):
-		r, g, b, alpha = rgba
-		ri, gi, bi = rgb_indexes
-
+	def rgb(self,
+		r: _number | _percentage = _number(0),
+		g: _number | _percentage = _number(0),
+		b: _number | _percentage = _number(0)):
 		try:
 			r = r.to_byte()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(ri, str(e))
+			raise _InvalidArgumentValueError(0, str(e))
 
 		try:
 			g = g.to_byte()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(gi, str(e))
+			raise _InvalidArgumentValueError(1, str(e))
 
 		try:
 			b = b.to_byte()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(bi, str(e))
-
-		try:
-			alpha = alpha.to_factor()
-		except ValueError as e:
-			raise _InvalidArgumentValueError(3, str(e))
-
-		return _Reference.color(_Color(_Color.Type.RGB, r, g, b, alpha))
-
-	# ---
-	# Functions.
-	# ---
+			raise _InvalidArgumentValueError(2, str(e))
 
-	def rgb(self, r: number | percentage,
-		g: number | percentage = number(0),
-		b: number | percentage = number(0)):
-		return self._rgb((r, g, b, 1.0), (0, 1, 2))
+		return _Reference.color(_RGBColor(r / 255, g / 255, b / 255, 1.0))
 
 class CSS2Reference(CSS1Reference):
 	""" Named colors from `CSS Level 2 (Revision 1)
 		<https://www.w3.org/TR/CSS2/>`_. """
 
-	def __init__(self, *args, **kwargs):
-		super().__init__(*args, **kwargs)
-
-	# ---
-	# Named colors.
-	# ---
-
-	__colors = {
-		'orange': _rgb('#ffa500')}
-
-	def _color(self, name):
-		try:
-			return self.__colors[name]
-		except:
-			return super()._color(name)
+	orange = _rgb('#ffa500')
 
 class CSS3Reference(CSS2Reference):
 	""" Named colors and functions from `CSS Color Module Level 3
 		<https://drafts.csswg.org/css-color-3/>`_. """
 
-	number = _Reference.number
-	percentage = _Reference.percentage
-	angle = _Reference.angle
-	color = _Reference.color
-
-	def __init__(self, *args, **kwargs):
-		super().__init__(*args, **kwargs)
+	darkblue = _rgb('#00008B')
+	mediumblue = _rgb('#0000CD')
+	darkgreen = _rgb('#006400')
+	darkcyan = _rgb('#008B8B')
+	deepskyblue = _rgb('#00BFFF')
+	darkturquoise = _rgb('#00CED1')
+	mediumspringgreen = _rgb('#00FA9A')
+	springgreen = _rgb('#00FF7F')
+	cyan = _rgb('#00FFFF')
+	midnightblue = _rgb('#191970')
+	dodgerblue = _rgb('#1E90FF')
+	lightseagreen = _rgb('#20B2AA')
+	forestgreen = _rgb('#228B22')
+	seagreen = _rgb('#2E8B57')
+	darkslategray = _rgb('#2F4F4F')
+	darkslategrey = _rgb('#2F4F4F')
+	limegreen = _rgb('#32CD32')
+	mediumseagreen = _rgb('#3CB371')
+	turquoise = _rgb('#40E0D0')
+	royalblue = _rgb('#4169E1')
+	steelblue = _rgb('#4682B4')
+	darkslateblue = _rgb('#483D8B')
+	mediumturquoise = _rgb('#48D1CC')
+	indigo = _rgb('#4B0082')
+	darkolivegreen = _rgb('#556B2F')
+	cadetblue = _rgb('#5F9EA0')
+	cornflowerblue = _rgb('#6495ED')
+	mediumaquamarine = _rgb('#66CDAA')
+	dimgray = _rgb('#696969')
+	dimgrey = _rgb('#696969')
+	slateblue = _rgb('#6A5ACD')
+	olivedrab = _rgb('#6B8E23')
+	slategray = _rgb('#708090')
+	slategrey = _rgb('#708090')
+	lightslategray = _rgb('#778899')
+	lightslategrey = _rgb('#778899')
+	mediumslateblue = _rgb('#7B68EE')
+	lawngreen = _rgb('#7CFC00')
+	chartreuse = _rgb('#7FFF00')
+	aquamarine = _rgb('#7FFFD4')
+	grey = _rgb('#808080')
+	skyblue = _rgb('#87CEEB')
+	lightskyblue = _rgb('#87CEFA')
+	blueviolet = _rgb('#8A2BE2')
+	darkred = _rgb('#8B0000')
+	darkmagenta = _rgb('#8B008B')
+	saddlebrown = _rgb('#8B4513')
+	darkseagreen = _rgb('#8FBC8F')
+	lightgreen = _rgb('#90EE90')
+	mediumpurple = _rgb('#9370DB')
+	darkviolet = _rgb('#9400D3')
+	palegreen = _rgb('#98FB98')
+	darkorchid = _rgb('#9932CC')
+	yellowgreen = _rgb('#9ACD32')
+	sienna = _rgb('#A0522D')
+	brown = _rgb('#A52A2A')
+	darkgray = _rgb('#A9A9A9')
+	darkgrey = _rgb('#A9A9A9')
+	lightblue = _rgb('#ADD8E6')
+	greenyellow = _rgb('#ADFF2F')
+	paleturquoise = _rgb('#AFEEEE')
+	lightsteelblue = _rgb('#B0C4DE')
+	powderblue = _rgb('#B0E0E6')
+	firebrick = _rgb('#B22222')
+	darkgoldenrod = _rgb('#B8860B')
+	mediumorchid = _rgb('#BA55D3')
+	rosybrown = _rgb('#BC8F8F')
+	darkkhaki = _rgb('#BDB76B')
+	mediumvioletred = _rgb('#C71585')
+	indianred = _rgb('#CD5C5C')
+	peru = _rgb('#CD853F')
+	chocolate = _rgb('#D2691E')
+	tan = _rgb('#D2B48C')
+	lightgray = _rgb('#D3D3D3')
+	lightgrey = _rgb('#D3D3D3')
+	thistle = _rgb('#D8BFD8')
+	orchid = _rgb('#DA70D6')
+	goldenrod = _rgb('#DAA520')
+	palevioletred = _rgb('#DB7093')
+	crimson = _rgb('#DC143C')
+	gainsboro = _rgb('#DCDCDC')
+	plum = _rgb('#DDA0DD')
+	burlywood = _rgb('#DEB887')
+	lightcyan = _rgb('#E0FFFF')
+	lavender = _rgb('#E6E6FA')
+	darksalmon = _rgb('#E9967A')
+	violet = _rgb('#EE82EE')
+	palegoldenrod = _rgb('#EEE8AA')
+	lightcoral = _rgb('#F08080')
+	khaki = _rgb('#F0E68C')
+	aliceblue = _rgb('#F0F8FF')
+	honeydew = _rgb('#F0FFF0')
+	azure = _rgb('#F0FFFF')
+	sandybrown = _rgb('#F4A460')
+	wheat = _rgb('#F5DEB3')
+	beige = _rgb('#F5F5DC')
+	whitesmoke = _rgb('#F5F5F5')
+	mintcream = _rgb('#F5FFFA')
+	ghostwhite = _rgb('#F8F8FF')
+	salmon = _rgb('#FA8072')
+	antiquewhite = _rgb('#FAEBD7')
+	linen = _rgb('#FAF0E6')
+	lightgoldenrodyellow = _rgb('#FAFAD2')
+	oldlace = _rgb('#FDF5E6')
+	magenta = _rgb('#FF00FF')
+	deeppink = _rgb('#FF1493')
+	orangered = _rgb('#FF4500')
+	tomato = _rgb('#FF6347')
+	hotpink = _rgb('#FF69B4')
+	coral = _rgb('#FF7F50')
+	darkorange = _rgb('#FF8C00')
+	lightsalmon = _rgb('#FFA07A')
+	lightpink = _rgb('#FFB6C1')
+	pink = _rgb('#FFC0CB')
+	gold = _rgb('#FFD700')
+	peachpuff = _rgb('#FFDAB9')
+	navajowhite = _rgb('#FFDEAD')
+	moccasin = _rgb('#FFE4B5')
+	bisque = _rgb('#FFE4C4')
+	mistyrose = _rgb('#FFE4E1')
+	blanchedalmond = _rgb('#FFEBCD')
+	papayawhip = _rgb('#FFEFD5')
+	lavenderblush = _rgb('#FFF0F5')
+	seashell = _rgb('#FFF5EE')
+	cornsilk = _rgb('#FFF8DC')
+	lemonchiffon = _rgb('#FFFACD')
+	floralwhite = _rgb('#FFFAF0')
+	snow = _rgb('#FFFAFA')
+	lightyellow = _rgb('#FFFFE0')
+	ivory = _rgb('#FFFFF0')
 
 	# ---
-	# Named colors.
-	# ---
-
-	__colors = {
-		'darkblue':             _rgb('#00008B'),
-		'mediumblue':           _rgb('#0000CD'),
-		'darkgreen':            _rgb('#006400'),
-		'darkcyan':             _rgb('#008B8B'),
-		'deepskyblue':          _rgb('#00BFFF'),
-		'darkturquoise':        _rgb('#00CED1'),
-		'mediumspringgreen':    _rgb('#00FA9A'),
-		'springgreen':          _rgb('#00FF7F'),
-		'cyan':                 _rgb('#00FFFF'),
-		'midnightblue':         _rgb('#191970'),
-		'dodgerblue':           _rgb('#1E90FF'),
-		'lightseagreen':        _rgb('#20B2AA'),
-		'forestgreen':          _rgb('#228B22'),
-		'seagreen':             _rgb('#2E8B57'),
-		'darkslategray':        _rgb('#2F4F4F'),
-		'darkslategrey':        _rgb('#2F4F4F'),
-		'limegreen':            _rgb('#32CD32'),
-		'mediumseagreen':       _rgb('#3CB371'),
-		'turquoise':            _rgb('#40E0D0'),
-		'royalblue':            _rgb('#4169E1'),
-		'steelblue':            _rgb('#4682B4'),
-		'darkslateblue':        _rgb('#483D8B'),
-		'mediumturquoise':      _rgb('#48D1CC'),
-		'indigo':               _rgb('#4B0082'),
-		'darkolivegreen':       _rgb('#556B2F'),
-		'cadetblue':            _rgb('#5F9EA0'),
-		'cornflowerblue':       _rgb('#6495ED'),
-		'mediumaquamarine':     _rgb('#66CDAA'),
-		'dimgray':              _rgb('#696969'),
-		'dimgrey':              _rgb('#696969'),
-		'slateblue':            _rgb('#6A5ACD'),
-		'olivedrab':            _rgb('#6B8E23'),
-		'slategray':            _rgb('#708090'),
-		'slategrey':            _rgb('#708090'),
-		'lightslategray':       _rgb('#778899'),
-		'lightslategrey':       _rgb('#778899'),
-		'mediumslateblue':      _rgb('#7B68EE'),
-		'lawngreen':            _rgb('#7CFC00'),
-		'chartreuse':           _rgb('#7FFF00'),
-		'aquamarine':           _rgb('#7FFFD4'),
-		'grey':                 _rgb('#808080'),
-		'skyblue':              _rgb('#87CEEB'),
-		'lightskyblue':         _rgb('#87CEFA'),
-		'blueviolet':           _rgb('#8A2BE2'),
-		'darkred':              _rgb('#8B0000'),
-		'darkmagenta':          _rgb('#8B008B'),
-		'saddlebrown':          _rgb('#8B4513'),
-		'darkseagreen':         _rgb('#8FBC8F'),
-		'lightgreen':           _rgb('#90EE90'),
-		'mediumpurple':         _rgb('#9370DB'),
-		'darkviolet':           _rgb('#9400D3'),
-		'palegreen':            _rgb('#98FB98'),
-		'darkorchid':           _rgb('#9932CC'),
-		'yellowgreen':          _rgb('#9ACD32'),
-		'sienna':               _rgb('#A0522D'),
-		'brown':                _rgb('#A52A2A'),
-		'darkgray':             _rgb('#A9A9A9'),
-		'darkgrey':             _rgb('#A9A9A9'),
-		'lightblue':            _rgb('#ADD8E6'),
-		'greenyellow':          _rgb('#ADFF2F'),
-		'paleturquoise':        _rgb('#AFEEEE'),
-		'lightsteelblue':       _rgb('#B0C4DE'),
-		'powderblue':           _rgb('#B0E0E6'),
-		'firebrick':            _rgb('#B22222'),
-		'darkgoldenrod':        _rgb('#B8860B'),
-		'mediumorchid':         _rgb('#BA55D3'),
-		'rosybrown':            _rgb('#BC8F8F'),
-		'darkkhaki':            _rgb('#BDB76B'),
-		'mediumvioletred':      _rgb('#C71585'),
-		'indianred':            _rgb('#CD5C5C'),
-		'peru':                 _rgb('#CD853F'),
-		'chocolate':            _rgb('#D2691E'),
-		'tan':                  _rgb('#D2B48C'),
-		'lightgray':            _rgb('#D3D3D3'),
-		'lightgrey':            _rgb('#D3D3D3'),
-		'thistle':              _rgb('#D8BFD8'),
-		'orchid':               _rgb('#DA70D6'),
-		'goldenrod':            _rgb('#DAA520'),
-		'palevioletred':        _rgb('#DB7093'),
-		'crimson':              _rgb('#DC143C'),
-		'gainsboro':            _rgb('#DCDCDC'),
-		'plum':                 _rgb('#DDA0DD'),
-		'burlywood':            _rgb('#DEB887'),
-		'lightcyan':            _rgb('#E0FFFF'),
-		'lavender':             _rgb('#E6E6FA'),
-		'darksalmon':           _rgb('#E9967A'),
-		'violet':               _rgb('#EE82EE'),
-		'palegoldenrod':        _rgb('#EEE8AA'),
-		'lightcoral':           _rgb('#F08080'),
-		'khaki':                _rgb('#F0E68C'),
-		'aliceblue':            _rgb('#F0F8FF'),
-		'honeydew':             _rgb('#F0FFF0'),
-		'azure':                _rgb('#F0FFFF'),
-		'sandybrown':           _rgb('#F4A460'),
-		'wheat':                _rgb('#F5DEB3'),
-		'beige':                _rgb('#F5F5DC'),
-		'whitesmoke':           _rgb('#F5F5F5'),
-		'mintcream':            _rgb('#F5FFFA'),
-		'ghostwhite':           _rgb('#F8F8FF'),
-		'salmon':               _rgb('#FA8072'),
-		'antiquewhite':         _rgb('#FAEBD7'),
-		'linen':                _rgb('#FAF0E6'),
-		'lightgoldenrodyellow': _rgb('#FAFAD2'),
-		'oldlace':              _rgb('#FDF5E6'),
-		'magenta':              _rgb('#FF00FF'),
-		'deeppink':             _rgb('#FF1493'),
-		'orangered':            _rgb('#FF4500'),
-		'tomato':               _rgb('#FF6347'),
-		'hotpink':              _rgb('#FF69B4'),
-		'coral':                _rgb('#FF7F50'),
-		'darkorange':           _rgb('#FF8C00'),
-		'lightsalmon':          _rgb('#FFA07A'),
-		'lightpink':            _rgb('#FFB6C1'),
-		'pink':                 _rgb('#FFC0CB'),
-		'gold':                 _rgb('#FFD700'),
-		'peachpuff':            _rgb('#FFDAB9'),
-		'navajowhite':          _rgb('#FFDEAD'),
-		'moccasin':             _rgb('#FFE4B5'),
-		'bisque':               _rgb('#FFE4C4'),
-		'mistyrose':            _rgb('#FFE4E1'),
-		'blanchedalmond':       _rgb('#FFEBCD'),
-		'papayawhip':           _rgb('#FFEFD5'),
-		'lavenderblush':        _rgb('#FFF0F5'),
-		'seashell':             _rgb('#FFF5EE'),
-		'cornsilk':             _rgb('#FFF8DC'),
-		'lemonchiffon':         _rgb('#FFFACD'),
-		'floralwhite':          _rgb('#FFFAF0'),
-		'snow':                 _rgb('#FFFAFA'),
-		'lightyellow':          _rgb('#FFFFE0'),
-		'ivory':                _rgb('#FFFFF0')}
-
-	def _color(self, name):
-		try:
-			return self.__colors[name]
-		except:
-			return super()._color(name)
-
-	# ---
-	# Utilities.
+	# Functions.
 	# ---
 
-	def _hsl(self, hsla, hsl_indexes):
-		h, s, l, alpha = hsla
-		hi, si, li = hsl_indexes
+	def hsl(self,
+		h: _number | _angle,
+		s: _number | _percentage,
+		l: _number | _percentage,
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			h = h.to_hue()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(hi, str(e))
+			raise _InvalidArgumentValueError(0, str(e))
 
 		try:
 			s = s.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(si, str(e))
+			raise _InvalidArgumentValueError(1, str(e))
 
 		try:
 			l = l.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(li, str(e))
+			raise _InvalidArgumentValueError(2, str(e))
 
 		try:
 			alpha = alpha.to_factor()
 		except ValueError as e:
 			raise _InvalidArgumentValueError(3, str(e))
 
-		return _Reference.color(_Color(_Color.Type.HSL, h, s, l, alpha))
+		return _Reference.color(_HSLColor(h, s, l, alpha))
 
-	# ---
-	# Functions.
-	# ---
-
-	@_Reference.alias('rgba')
-	def rgb(self, r: number | percentage,
-		g: number | percentage = number(0), b: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (0, 1, 2))
-
-	@_Reference.alias('hsla')
-	def hsl(self, h: number | angle, s: number | percentage,
-		l: number | percentage, alpha: number | percentage = number(1.0)):
-		return self._hsl((h, s, l, alpha), (0, 1, 2))
+	rgba = _alias('rgb')
+	hsla = _alias('hsla')
 
 class CSS4Reference(CSS3Reference):
 	""" Named colors and functions from `CSS Color Module Level 4
 		<https://drafts.csswg.org/css-color/>`_. """
 
-	def __init__(self, *args, **kwargs):
-		super().__init__(*args, **kwargs)
-
-	number = _Reference.number
-	percentage = _Reference.percentage
-	angle = _Reference.angle
-	color = _Reference.color
+	rebeccapurple = _rgb('#663399')
 
 	# ---
-	# Named colors.
-	# ---
-
-	__colors = {
-		'rebeccapurple': _rgb('#663399')}
-
-	def _color(self, name):
-		try:
-			return self.__colors[name]
-		except:
-			return super()._color(name)
-
-	# ---
-	# Utilities.
+	# Functions.
 	# ---
 
-	def _hwb(self, hwba, hwb_indexes):
-		h, w, b, alpha = hwba
-		hi, wi, bi = hwb_indexes
+	def hwb(self, h: _number | _angle,
+		w: _number | _percentage = _number(0),
+		b: _number | _percentage = _number(0),
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			h = h.to_hue()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(hi, str(e))
+			raise _InvalidArgumentValueError(0, str(e))
 
 		try:
 			w = w.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(wi, str(e))
+			raise _InvalidArgumentValueError(1, str(e))
 
 		try:
 			b = b.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(bi, str(e))
+			raise _InvalidArgumentValueError(2, str(e))
 
 		try:
 			alpha = alpha.to_factor()
 		except ValueError as e:
 			raise _InvalidArgumentValueError(3, str(e))
 
-		return _Reference.color(_Color(_Color.Type.HWB, h, w, b, alpha))
+		return _Reference.color(_HWBColor(h, w, b, alpha))
 
-	# ---
-	# Functions.
-	# ---
-
-	@_Reference.alias('hwba')
-	def hwb(self, h: number | angle, w: number | percentage = number(0),
-		b: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._hwb((h, w, b, alpha), (0, 1, 2))
+	def gray(self, g: _number | _percentage,
+		alpha: _number | _percentage = _number(1.0)):
 
-	def gray(self, g: number | percentage,
-		alpha: number | percentage = number(1.0)):
 		try:
 			g = g.to_byte()
 		except ValueError as e:
@@ -397,10 +299,11 @@ class CSS4Reference(CSS3Reference):
 		except ValueError as e:
 			raise _InvalidArgumentValueError(1, str(e))
 
-		return _Reference.color(_Color(_Color.Type.RGB, g, g, g, alpha))
+		g /= 255
+		return _Reference.color(_RGBColor(g, g, g, alpha))
 
-	def lab(self, l: number, a: number, b: number,
-		alpha: number | percentage = number(1.0)):
+	def lab(self, l: _number, a: _number, b: _number,
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			l = l.value
@@ -418,10 +321,10 @@ class CSS4Reference(CSS3Reference):
 		except ValueError as e:
 			raise _InvalidArgumentValueError(3, str(e))
 
-		return _Reference.color(_Color(_Color.Type.LAB, l, a, b, alpha))
+		return _Reference.color(_LABColor(l, a, b, alpha))
 
-	def lch(self, l: number, c: number, h: number | angle,
-		alpha: number | percentage = number(1.0)):
+	def lch(self, l: _number, c: _number, h: _number | _angle,
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			l = l.value
@@ -445,6 +348,8 @@ class CSS4Reference(CSS3Reference):
 		except ValueError as e:
 			raise _InvalidArgumentValueError(3, str(e))
 
-		return _Reference.color(_Color(_Color.Type.LCH, l, c, h, alpha))
+		return _Reference.color(_LCHColor(l, c, h, alpha))
+
+	hwba = _alias('hwb')
 
 # End of file.
diff --git a/thcolor/builtin/_default.py b/thcolor/builtin/_default.py
index dd54a2b..ca1c066 100755
--- a/thcolor/builtin/_default.py
+++ b/thcolor/builtin/_default.py
@@ -1,117 +1,96 @@
 #!/usr/bin/env python3
-#******************************************************************************
+#**************************************************************************
 # Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
-""" Named colors and function definitions. Color names are case-insensitive.
-	Extends the CSS references. """
+#**************************************************************************
+""" Named colors and function definitions. Color names are
+	case-insensitive. Extends the CSS references. """
 
 from .._color import Color as _Color
 from .._ref import Reference as _Reference
+from .._exc import InvalidArgumentValueError as _InvalidArgumentValueError
 from ._css import CSS4Reference as _CSS4Reference
+from ..syntax import (number as _number, percentage as _percentage,
+	angle as _angle, color as _color, alias as _alias)
 
 __all__ = ["DefaultReference"]
 
+
 class DefaultReference(_CSS4Reference):
 	""" Functions extending the CSS Color Module Level 4 reference. """
 
 	def __init__(self, *args, **kwargs):
 		super().__init__(*args, **kwargs)
 
-	number = _Reference.number
-	percentage = _Reference.percentage
-	angle = _Reference.angle
-	color = _Reference.color
-
 	# ---
-	# RGB functions.
+	# Color functions.
 	# ---
 
-	@_Reference.alias('rbga')
-	def rbg(self, r: number | percentage,
-		b: number | percentage = number(0), g: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (0, 2, 1))
-
-	@_Reference.alias('brga')
-	def brg(self, b: number | percentage,
-		r: number | percentage = number(0), g: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (1, 2, 0))
-
-	@_Reference.alias('bgra')
-	def bgr(self, b: number | percentage,
-		g: number | percentage = number(0), r: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (2, 1, 0))
-
-	@_Reference.alias('gbra')
-	def gbr(self, g: number | percentage,
-		b: number | percentage = number(0), r: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (2, 0, 1))
-
-	@_Reference.alias('grba')
-	def grb(self, g: number | percentage,
-		r: number | percentage = number(0), b: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._rgb((r, g, b, alpha), (1, 0, 2))
+	@_alias('rbg', 'rbga', arg_order=(0, 2, 1))
+	@_alias('brg', 'brga', arg_order=(2, 0, 1))
+	@_alias('bgr', 'bgra', arg_order=(2, 1, 0))
+	@_alias('gbr', 'gbra', arg_order=(1, 2, 0))
+	@_alias('grb', 'grba', arg_order=(1, 0, 2))
+	def rgb(self, r: _number | _percentage = _number(0),
+		g: _number | _percentage = _number(0),
+		b: _number | _percentage = _number(0),
+		alpha: _number | _percentage = _number(1.0)):
 
-	# ---
-	# HLS and HWB aliases.
-	# ---
+		return super().rgb(r, g, b, alpha)
 
-	@_Reference.alias('hlsa')
-	def hls(self, h: number | angle, l: number | percentage,
-		s: number | percentage, alpha: number | percentage = number(1.0)):
-		return self._hsl((h, s, l, alpha), (0, 2, 1))
+	@_alias('hls', 'hlsa', arg_order=(0, 2, 1))
+	def hsl(self, h: _number | _angle, s: _number | _percentage,
+		l: _number | _percentage,
+		alpha: _number | _percentage = _number(1.0)):
 
-	@_Reference.alias('hbwa')
-	def hbw(self, h: number | angle, b: number | percentage = number(0),
-		w: number | percentage = number(0),
-		alpha: number | percentage = number(1.0)):
-		return self._hwb((h, w, b, alpha), (0, 2, 1))
+		return super().hsl(h, s, l, alpha)
 
-	# ---
-	# CMYK utilities and extensions.
-	# ---
+	@_alias('hbw', 'hbwa', arg_order=(0, 2, 1))
+	def hwb(self, h: _number | _angle,
+		w: _number | _percentage = _number(0),
+		b: _number | _percentage = _number(0),
+		alpha: _number | _percentage = _number(1.0)):
 
-	def cmyk(self, c: number | percentage,
-		m: number | percentage = percentage(0),
-		y: number | percentage = percentage(0),
-		k = number | percentage(0),
-		alpha: number | percentage = number(1.0)):
-		ci, mi, yi, ki = 0, 1, 2, 3
+		return super().hwb(h, w, b, alpha)
+
+	@_alias('device-cmyk')
+	def cmyk(self, c: _number | _percentage,
+		m: _number | _percentage = _percentage(0),
+		y: _number | _percentage = _percentage(0),
+		k: _number | _percentage = _percentage(0),
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			c = c.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(ci, str(e))
+			raise _InvalidArgumentValueError(0, str(e))
 
 		try:
 			m = m.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(mi, str(e))
+			raise _InvalidArgumentValueError(1, str(e))
 
 		try:
 			y = y.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(yi, str(e))
+			raise _InvalidArgumentValueError(2, str(e))
 
 		try:
 			k = k.to_factor()
 		except ValueError as e:
-			raise _InvalidArgumentValueError(ki, str(e))
+			raise _InvalidArgumentValueError(3, str(e))
 
 		try:
 			alpha = alpha.to_factor()
 		except ValueError as e:
 			raise _InvalidArgumentValueError(4, str(e))
 
-		return _Reference.color(_Color(_Color.Type.CMYK, c, m, y, k, alpha))
+		return _Reference.color(_Color(_Color.Type.CMYK, c, m, y, k,
+			alpha))
 
-	def xyz(self, x: number | percentage, y: number | percentage,
-		z: number | percentage, alpha: number | percentage = number(1.0)):
+	def xyz(self, x: _number | _percentage,
+		y: _number | _percentage, z: _number | _percentage,
+		alpha: _number | _percentage = _number(1.0)):
 
 		try:
 			x = x.to_factor()
@@ -139,15 +118,15 @@ class DefaultReference(_CSS4Reference):
 	# Get the RGB components of a color.
 	# ---
 
-	def red(self, col: color) -> number:
+	def red(self, col: _color) -> _number:
 		r, g, b = col.to_color().rgb()
 		return _Reference.number(r)
 
-	def green(self, col: color) -> number:
+	def green(self, col: _color) -> _number:
 		r, g, b = col.to_color().rgb()
 		return _Reference.number(g)
 
-	def blue(self, col: color) -> number:
+	def blue(self, col: _color) -> _number:
 		r, g, b = col.to_color().rgb()
 		return _Reference.number(b)
 
@@ -155,7 +134,7 @@ class DefaultReference(_CSS4Reference):
 	# Manage the lightness and saturation for HSL colors.
 	# ---
 
-	def darker(self, by: number | percentage, col: color) -> color:
+	def darker(self, by: _number | _percentage, col: _color) -> _color:
 		try:
 			by = by.to_factor()
 		except ValueError as e:
@@ -171,7 +150,7 @@ class DefaultReference(_CSS4Reference):
 
 		return _Reference.color(_Color(_Color.Type.HSL, h, s, l, a))
 
-	def lighter(self, by: number | percentage, col: color) -> color:
+	def lighter(self, by: _number | _percentage, col: _color) -> _color:
 		try:
 			by = by.to_factor()
 		except ValueError as e:
@@ -187,7 +166,7 @@ class DefaultReference(_CSS4Reference):
 
 		return _Reference.color(_Color(_Color.Type.HSL, h, s, l, a))
 
-	def desaturate(self, by: number | percentage, col: color) -> color:
+	def desaturate(self, by: _number | _percentage, col: _color) -> _color:
 		try:
 			by = by.to_factor()
 		except ValueError as e:
@@ -203,7 +182,7 @@ class DefaultReference(_CSS4Reference):
 
 		return _Reference.color(_Color(_Color.Type.HSL, h, s, l, a))
 
-	def saturate(self, by: number | percentage, col: color) -> color:
+	def saturate(self, by: _number | _percentage, col: _color) -> _color:
 		try:
 			by = by.to_factor()
 		except ValueError as e:
@@ -223,7 +202,7 @@ class DefaultReference(_CSS4Reference):
 	# Others.
 	# ---
 
-	def ncol(self, col: color) -> color:
+	def ncol(self, col: _color) -> _color:
 		# Compatibility with w3color.js! NCols are managed directly without
 		# the function, so the function doesn't do anything.
 
diff --git a/thcolor/colors.py b/thcolor/colors.py
new file mode 100644
index 0000000..0d0acf0
--- /dev/null
+++ b/thcolor/colors.py
@@ -0,0 +1,966 @@
+#!/usr/bin/env python3
+#**************************************************************************
+# Copyright (C) 2019-2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+# This file is part of the thcolor project, which is MIT-licensed.
+#**************************************************************************
+""" Color representations and conversions. """
+
+from typing import Tuple as _Tuple
+from collections.abc import Sequence as _Sequence, Mapping as _Mapping
+from math import (ceil as _ceil, atan2 as _atan2, sqrt as _sqrt,
+	cos as _cos, sin as _sin, pow as _pow)
+
+from .angles import (Angle as _Angle, DegreesAngle as _DegreesAngle,
+	RadiansAngle as _RadiansAngle)
+
+__all__ = ['Color',
+	'SRGBColor', 'HSLColor', 'HWBColor', 'CMYKColor',
+	'LABColor', 'LCHColor', 'XYZColor']
+
+_color_pattern = None
+
+class Color:
+	""" Class representing a color within thcolor.
+
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_alpha')
+	_params = ()
+
+	def __init__(self, alpha: float = 1.0):
+		super().__init__()
+
+		self._alpha = alpha
+
+	def __repr__(self):
+		params = ((key, getattr(self, key))
+			for key in self._params + ('alpha',))
+		return (f"{self.__class__.__name__}("
+			f"{', '.join(f'{key} = {repr(val)}' for key, val in params)})")
+
+	@property
+	def alpha(self) -> float:
+		""" The alpha component value, varying between 0.0 (invisible)
+			and 1.0 (opaque). """
+
+		return self._alpha
+
+	# ---
+	# Conversions.
+	# ---
+
+	def assrgb(self) -> 'SRGBColor':
+		""" Get an SRGBColor out of the current object. """
+
+		raise NotImplementedError
+
+	def ashsl(self) -> 'HSLColor':
+		""" Get an HSLColor out of the current object. """
+
+		return self.assrgb().ashsl()
+
+	def ashwb(self) -> 'HWBColor':
+		""" Get an HWBColor out of the current object. """
+
+		return self.assrgb().ashwb()
+
+	def ascmyk(self) -> 'CMYKColor':
+		""" Get a CMYKColor out of the current object. """
+
+		return self.assrgb().ascmyk()
+
+	def aslab(self) -> 'LABColor':
+		""" Get a LABColor out of the current object. """
+
+		raise NotImplementedError
+
+	def aslch(self) -> 'LCHColor':
+		""" Get a LCHColor out of the current object. """
+
+		raise NotImplementedError
+
+	def asxyz(self) -> 'XYZColor':
+		""" Get an XYZColor out of the current object. """
+
+		raise NotImplementedError
+
+	# ---
+	# Operations on colors.
+	# ---
+
+	def replace(self, **properties: _Mapping[str, object]) -> 'Color':
+		""" Replace components and obtain a copy of the color.
+			Returns a copy of the color with the property values replaced.
+
+			For changing the alpha on an RGB color:
+
+			.. code-block:: python
+
+				color = _RGBColor(1, 2, 3).replace(alpha = .5)
+
+			For changing the lightness on an HSL color:
+
+			.. code-block:: python
+
+				angle = _DegreesAngle(270)
+				color = _HSLColor(angle, .5, 1).replace(lightness = .2)
+
+			:param properties: Properties to change from the original
+			                   color. """
+
+		params = {key: getattr(self, key) for key in self._params + ('alpha',)}
+
+		for key, value in properties.items():
+			if not key in params:
+				raise KeyError(f"no such argument {repr(key)} in "
+					f"{self.__class__.__name__} parameters")
+
+			params[key] = value
+
+		return type(self)(**params)
+
+	def darker(self, by: float = 0.1) -> 'HSLColor':
+		""" Get a darker version of the given color.
+
+			:param by: Percentage by which the color should be darker. """
+
+		color = self.ashsl()
+		return color.replace(lightness = max(color.lightness - by, 0.0))
+
+	def lighter(self, by: float = 0.1) -> 'HSLColor':
+		""" Get a lighter version of the given color.
+
+			:param by: Percentage by which the color should be lighter. """
+
+		color = self.ashsl()
+		return color.replace(lightness = min(color.lightness + by, 1.0))
+
+	def desaturate(self, by: float = 0.1) -> 'HSLColor':
+		""" Get a less saturated version of the given color.
+
+			:param by: Percentage by which the color should be
+			           desaturated.  """
+
+		color = self.ashsl()
+		return color.replace(saturation = max(color.saturation - by, 0.0))
+
+	def saturate(self, by: float = 0.1) -> 'HSLColor':
+		""" Get a more saturated version of the given color.
+
+			:param by: Percentage by which the color should be
+			           saturated.  """
+
+		color = self.ashsl()
+		return color.replace(saturation = min(color.saturation + by, 1.0))
+
+	# ---
+	# CSS utilities.
+	# ---
+
+	def css(self) -> _Sequence[str]:
+		""" Get the CSS color descriptions, with older CSS specifications
+			compatibility, as a sequence of strings.
+
+			For example:
+
+				>>> SRGBColor(18, 52, 86, 0.82).css()
+				... ("#123456", "rgba(18, 52, 86, 82%)") """
+
+		def _percent(prop):
+			per = round(prop, 4) * 100
+			if per == int(per):
+				per = int(per)
+			return per
+
+		def _deg(agl):
+			agl = round(agl.asdegrees().degrees, 2)
+			if agl == int(agl):
+				agl = int(agl)
+			return agl
+
+		def statements():
+			# Start by yelling a #RRGGBB color, compatible with most
+			# web browsers around the world, followed by the rgba()
+			# notation if the alpha value isn't 1.0.
+
+			a = round(self.alpha, 3)
+
+			try:
+				rgb = self.assrgb()
+			except NotImplementedError:
+				pass
+			else:
+				r, g, b = (int(rgb.red * 255), int(rgb.green * 255),
+					int(rgb.blue * 255))
+
+				yield f'#{r:02X}{g:02X}{b:02X}'
+
+				if a < 1.0:
+					yield f'rgba({r}, {g}, {b}, {_percent(a)}%)'
+
+			# Then yield more specific CSS declarations in case
+			# they're supported (which would be neat!).
+
+			if isinstance(self, HSLColor):
+				hue, sat, lgt = (
+					self.hue, self.saturation, self.lightness)
+
+				args = (f'{_deg(hue)}deg, '
+					f'{_percent(sat)}%, {_percent(lgt)}%')
+
+				if a < 1.0:
+					yield f'hsla({args}, {_percent(a)}%)'
+				else:
+					yield f'hsl({args})'
+			elif isinstance(self, HWBColor):
+				hue, wht, blk = (
+					self.hue, self.whiteness, self.blackness)
+
+				args = f'{_deg(hue)}deg, ' \
+					f'{_percent(wht)}%, {_percent(blk)}%'
+
+				if a < 1.0:
+					yield f'hwba({args}, {_percent(a)}%)'
+				else:
+					yield f'hwb({args})'
+
+		return tuple(statements())
+
+	# ---
+	# Static methods for decoding.
+	# ---
+
+	@staticmethod
+	def from_text(expr: str) -> 'Color':
+		""" Create a color from a string.
+
+			:param expr: The expression to decode. """
+
+		global _color_pattern
+
+		# Load the pattern if required.
+
+		if _color_pattern is None:
+			try:
+				import regex
+			except ImportError:
+				raise ImportError("text parsing is disabled until you "
+					"install the 'regex' module, e.g. via "
+					"'pip install regex'.")
+
+			_color_pattern = regex.compile(r"""
+				(
+					((?P<agl_val>-? ([0-9]+\.?|[0-9]*\.[0-9]+)) \s*
+						(?P<agl_typ>deg|grad|rad|turn))
+				| ((?P<per>[0-9]+(\.[0-9]*)? | \.[0-9]+) \s* \%)
+				|  (?P<num>[0-9]+(\.[0-9]*)? | \.[0-9]+)
+				|  (?P<ncol>[RYGCBM] [0-9]{0,2} (\.[0-9]*)?)
+				|  (\# (?P<hex>[0-9a-f]{3} | [0-9a-f]{4}
+					| [0-9a-f]{6} | [0-9a-f]{8}))
+				|  ((?P<name>[a-z]([a-z0-9\s_-]*[a-z0-9_-])?)
+					( \s* \( \s* (?P<arg> (?0)? ) \s* \) )?)
+				)
+
+				\s* ((?P<sep>[,/\s])+ \s* (?P<nextargs> (?0))?)?
+			""", regex.VERBOSE | regex.I | regex.M)
+
+		def recurse(column, match):
+			if not match:
+				return ()
+
+			args = recurse(column + match.start('nextargs'),
+				_color_pattern.fullmatch(match['nextargs'] or ""))
+
+			value = None
+			if match['agl_val'] is not None:
+				# The matched value is an angle.
+
+				agl_cls = {
+					'deg': _DegreesAngle,
+					'grad': _GradiansAngle,
+					'rad': _RadiansAngle,
+					'turn': _TurnsAngle
+				}[match['agl_typ']]
+
+				value = _angle(agl_cls(float(match['agl_val'])))
+			elif match['per'] is not None:
+				# The matched value is a percentage.
+
+				value = float(match['per'])
+				value = _percentage(value)
+			elif match['num'] is not None:
+				# The matched value is a number.
+
+				value = _number(match['num'])
+			elif match['hex'] is not None:
+				# The matched value is a hex color.
+
+				name = match['hex']
+
+				if len(name) <= 4:
+					name = ''.join(map(lambda x: x + x, name))
+
+				r = int(name[0:2], 16)
+				g = int(name[2:4], 16)
+				b = int(name[4:6], 16)
+				a = int(name[6:8], 16) / 255.0 if len(name) == 8 else 1.0
+
+				value = _color(_RGBColor.frombytes(r, g, b, a))
+			elif match['arg'] is not None:
+				# The matched value is a function.
+
+				name = match['name']
+				args = recurse(column + match.start('arg'),
+					_color_pattern.fullmatch(match['arg']))
+
+				# Get the function and call it with the arguments.
+				# TODO
+
+				raise _ColorExpressionDecodingError("not implemented",
+					column = column, func = name)
+			else:
+				# The match is probably a natural color (ncol), we ought
+				# to parse it and get the following arguments or, if
+				# anything is invalid, to treat it as a color name.
+				#
+				# Otherwise, it is a color name; use it directly as such.
+				# TODO: make ncol support not always available?
+
+				if match['ncol'] is not None:
+					name = match['ncol']
+
+					# First, get the letter and proportion.
+
+					letter = name[0]
+					number = float(name[1:])
+
+					if number >= 0 and number < 100:
+						# Get the following arguments and check.
+
+						try:
+							assert len(args) >= 2
+							w = args[0].value.to_factor()
+							b = args[1].value.to_factor()
+						except (AssertionError, TypeError, ValueError,
+							AttributeError):
+							w = 0
+							b = 0
+						else:
+							args = args[2:]
+
+						# Calculate the color and return the args.
+
+						angle_base = 'RYGCBM'.find(letter) * 60 \
+							+ number / 100 * 60
+						color = Color(Color.Type.HWB,
+							_Angle(_Angle.Type.DEG, angle_base, w, b))
+
+						value = _color(color)
+				else:
+					name = match['name']
+
+				if value is None:
+					# The matched value is a named color.
+
+					try:
+						# Get the named color (e.g. 'blue').
+
+						value = ref.colors[name]
+						assert value is not None
+					except AssertionError:
+						r, g, b = _netscape_color(name)
+						value = Color(Color.Type.RGB, r, g, b, 1.0)
+
+					value = _color(value)
+
+			return ((argument(column, value),) + args)
+
+		# Strip the expression.
+
+		lexpr = expr.strip()
+		column = (len(expr) - len(lexpr))
+		expr = lexpr
+		del lexpr
+
+		# Match the expression (and check it as a whole directly).
+
+		match = _color_pattern.fullmatch(expr)
+		if match is None:
+			raise _ColorExpressionDecodingError("expression parsing "
+				"failed")
+
+		# Get the result and check its type.
+
+		results = recurse(column, match)
+		if len(results) > 1:
+			raise _ColorExpressionDecodingError("extraneous value",
+				column = results[1].column)
+
+		result = results[0].value
+		try:
+			result = ref.colors[result]
+		except AttributeError:
+			raise _ColorExpressionDecodingError("expected a color",
+				column = column)
+
+		return result
+
+# ---
+# Color implementations.
+# ---
+
+class SRGBColor(Color):
+	""" A color expressed using its red, green and blue channel intensities
+		in the sRGB profile.
+
+		:param red: Value for :py:attr:`red`.
+		:param green: Value for :py:attr:`green`.
+		:param blue: Value for :py:attr:`blue`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_red', '_green', '_blue')
+	_params = ('red', 'green', 'blue')
+
+	def __init__(self, red: float, green: float, blue: float,
+		alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._red = red
+		self._green = green
+		self._blue = blue
+
+	@property
+	def red(self) -> float:
+		""" The intensity of the red channel, between 0.0 (dark)
+			and 1.0 (light). """
+
+		return self._red
+
+	@property
+	def green(self) -> float:
+		""" The intensity of the green channel, between 0.0 (dark)
+			and 1.0 (light). """
+
+		return self._green
+
+	@property
+	def blue(self) -> float:
+		""" The intensity of the blue channel, between 0.0 (dark)
+			and 1.0 (light). """
+
+		return self._blue
+
+	def assrgb(self) -> 'SRGBColor':
+		""" Get an SRGBColor out of the current object. """
+
+		return self
+
+	def ashsl(self) -> 'HSLColor':
+		""" Get an HSLColor out of the current object. """
+
+		r, g, b = self.red, self.green, self.blue
+
+		min_value = min((r, g, b))
+		max_value = max((r, g, b))
+		chroma = max_value - min_value
+
+		if   chroma == 0:
+			hue = 0
+		elif r == max_value:
+			hue = (g - b) / chroma
+		elif g == max_value:
+			hue = (b - r) / chroma + 2
+		else:
+			hue = (r - g) / chroma + 4
+
+		hue = hue * 60 + (hue < 0) * 360
+		lgt = (min_value + max_value) / 2
+		if min_value == max_value:
+			s = 0
+		else:
+			s = max_value - min_value
+			if lgt < 0.5:
+				s /= max_value + min_value
+			else:
+				s /= 2 - max_value - min_value
+
+		return _HSLColor(
+			hue = _DegreesAngle(round(hue, 2)),
+			saturation = round(s, 2),
+			lightness = round(lgt, 2),
+			alpha = self.alpha)
+
+	def ashwb(self) -> 'HWBColor':
+		""" Get an HWBColor out of the current object. """
+
+		r, g, b = self.red, self.green, self.blue
+
+		max_value = max((r, g, b))
+		min_value = min((r, g, b))
+		chroma = max_value - min_value
+
+		if   chroma == 0:
+			hue = 0
+		elif r == max_value:
+			hue = (g - b) / chroma
+		elif g == max_value:
+			hue = (b - r) / chroma + 2
+		elif g == max_value:
+			hue = (r - g) / chroma + 4
+
+		hue = (hue % 6) * 360
+		w = min_value
+		b = max_value
+
+		return _HWBColor(
+			hue = _DegreesAngle(hue),
+			whiteness = w,
+			blackness = b,
+			alpha = self.alpha)
+
+	def ascmyk(self) -> 'CMYKColor':
+		""" Get a CMYKColor out of the current object. """
+
+		r, g, b = self.red, self.green, self.blue
+
+		k = 1 - max((r, g, b))
+		if k == 1:
+			c, m, y = 0, 0, 0
+		else:
+			c = (1 - r - k) / (1 - k)
+			m = (1 - g - k) / (1 - k)
+			y = (1 - b - k) / (1 - k)
+
+		return CMYKColor(
+			cyan = c,
+			magenta = m,
+			yellow = y,
+			black = k,
+			alpha = self.alpha)
+
+	# ---
+	# Other utilities specific to sRGB.
+	# ---
+
+	@staticmethod
+	def frombytes(red: int, green: int, blue: int) -> 'SRGBColor':
+		""" Get an sRGB color from colors using values between 0 and 255. """
+
+		return SRGBColor(
+			red = red / 255,
+			green = green / 255,
+			blue = blue / 255)
+
+	@staticmethod
+	def fromnetscapecolorname(name: str) -> 'SRGBColor':
+		""" Get an sRGB color from a Netscape color name. """
+
+		name = str(name)
+
+		# Find more about this here: https://stackoverflow.com/a/8333464
+		#
+		# First of all:
+		# - we sanitize our input by replacing invalid characters
+		#   by '0' characters (the 0xFFFF limit is due to how
+		#   UTF-16 was managed at the time).
+		# - we truncate our input to 128 characters.
+
+		name = name.lower()
+		name = ''.join(c if c in '0123456789abcdef'
+			else ('0', '00')[ord(c) > 0xFFFF] for c in name[:128])[:128]
+
+		# Then we calculate some values we're going to need.
+		# `iv` is the size of the zone for a member.
+		# `sz` is the size of the digits slice to take in that zone
+		# (max. 8).
+		# `of` is the offset in the zone of the slice to take.
+
+		iv = _ceil(len(name) / 3)
+		of = iv - 8 if iv > 8 else 0
+		sz = iv - of
+
+		# Then we isolate the slices using the values calculated
+		# above. `gr` will be an array of 3 or 4 digit strings
+		# (depending on the number of members).
+
+		gr = list(map(lambda i: name[i * iv + of:i * iv + iv]
+			.ljust(sz, '0'), range(3)))
+
+		# Check how many digits we can skip at the beginning of
+		# each slice.
+
+		pre = min(map(lambda x: len(x) - len(x.lstrip('0')), gr))
+		pre = min(pre, sz - 2)
+
+		# Then we extract the values.
+
+		it = map(lambda x: int('0' + x[pre:pre + 2], 16), gr)
+		r, g, b = it
+
+		return SRGBColor.frombytes(r, g, b)
+
+
+class HSLColor(Color):
+	""" A color expressed using its hue, saturation and lightness (HSL)
+		components.
+
+		:param hue: Value for :py:attr:`hue`.
+		:param saturation: Value for :py:attr:`saturation`.
+		:param lightness: Value for :py:attr:`lightness`.
+		:param alpha: Value for :py:attr:`alpha`."""
+
+	__slots__ = ('_hue', '_saturation', '_lightness')
+	_params = ('hue', 'saturation', 'lightness')
+
+	def __init__(self, hue: _Angle, saturation: float, lightness: float,
+		alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._hue = hue
+		self._saturation = saturation
+		self._lightness = lightness
+
+	@property
+	def hue(self) -> _Angle:
+		""" The hue, as an angle. """
+
+		return self._hue
+
+	@property
+	def saturation(self) -> float:
+		""" The saturation, between 0.0 and 1.0. """
+
+		return self._saturation
+
+	@property
+	def lightness(self) -> float:
+		""" The lightness, between 0.0 and 1.0. """
+
+		return self._lightness
+
+	def assrgb(self) -> 'SRGBColor':
+		""" Get an SRGBColor out of the current object. """
+
+		lgt, hue, s = self.lightness, self.hue.asdegrees(), self.saturation
+
+		if s == 0:
+			# Achromatic color.
+
+			return lgt, lgt, lgt
+
+		def _hue_to_rgb(t1, t2, hue):
+			hue %= 6
+
+			if   hue < 1:
+				return t1 + (t2 - t1) * hue
+			elif hue < 3:
+				return t2
+			elif hue < 4:
+				return t1 + (t2 - t1) * (4 - hue)
+			return t1
+
+		hue = (hue.degrees % 360) / 60
+		if lgt <= 0.5:
+			t2 = lgt * (s + 1)
+		else:
+			t2 = lgt + s - (lgt * s)
+
+		t1 = lgt * 2 - t2
+
+		return SRGBColor(
+			red = _hue_to_rgb(t1, t2, hue + 2),
+			green = _hue_to_rgb(t1, t2, hue),
+			blue = _hue_to_rgb(t1, t2, hue - 2),
+			alpha = self.alpha)
+
+	def ashsl(self) -> 'HSLColor':
+		""" Get an HSLColor out of the current object. """
+
+		return self
+
+
+class HWBColor(Color):
+	""" A color expressed using its hue, whiteness and blackness
+		components.
+
+		:param hue: Value for :py:attr:`hue`.
+		:param whiteness: Value for :py:attr:`whiteness`.
+		:param blackness: Value for :py:attr:`blackness`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_hue', '_whiteness', '_blackness')
+	_params = ('hue', 'whiteness', 'blackness')
+
+	def __init__(self, hue: _Angle, whiteness: float, blackness: float,
+		alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._hue = hue
+		self._whiteness = whiteness
+		self._blackness = blackness
+
+	@property
+	def hue(self) -> _Angle:
+		""" The hue, as an angle. """
+
+		return self._hue
+
+	@property
+	def whiteness(self) -> float:
+		""" The whiteness, as a value between 0.0 and 1.0. """
+
+		return self._whiteness
+
+	@property
+	def blackness(self) -> float:
+		""" The blackness, as a value between 0.0 and 1.0. """
+
+		return self._blackness
+
+	def assrgb(self) -> 'SRGBColor':
+		""" Get an SRGBColor out of the current object. """
+
+		hue, w, bl = self.hue, self.whiteness, self.blackness
+
+		color = HSLColor(hue, .5, 1.0).assrgb()
+		r, g, b = color.red, color.green, color.blue
+
+		if w + bl > 1:
+			w, bl = map(lambda x: x / (w + bl), (w, bl))
+
+		r, g, b = map(lambda x: x * (1 - w - bl) + w, (r, g, b))
+
+		return SRGBColor(
+			red = r,
+			green = g,
+			blue = b,
+			alpha = self.alpha)
+
+	def ashwb(self) -> 'HWBColor':
+		""" Get an HWBColor out of the current object. """
+
+		return self
+
+
+class CMYKColor(Color):
+	""" A color expressed using its cyan, magenta, yellow and black
+		channel intensities.
+
+		:param cyan: Value for :py:attr:`cyan`.
+		:param magenta: Value for :py:attr:`magenta`.
+		:param yellow: Value for :py:attr:`yellow`.
+		:param black: Value for :py:attr:`black`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_cyan', '_magenta', '_yellow', '_black')
+	_params = ('cyan', 'magenta', 'yellow', 'black')
+
+	def __init__(self, cyan: float, magenta: float, yellow: float,
+		black: float, alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._cyan = cyan
+		self._magenta = magenta
+		self._yellow = yellow
+		self._black = black
+
+	@property
+	def cyan(self):
+		""" Cyan channel intensity between 0.0 and 1.0. """
+
+		return self._cyan
+
+	@property
+	def magenta(self):
+		""" Magenta channel intensity between 0.0 and 1.0. """
+
+		return self._magenta
+
+	@property
+	def yellow(self):
+		""" Yellow channel intensity between 0.0 and 1.0. """
+
+		return self._yellow
+
+	@property
+	def black(self):
+		""" Black channel intensity between 0.0 and 1.0. """
+
+		return self._black
+
+	def assrgb(self) -> 'SRGBColor':
+		""" Get an SRGBColor out of the current object. """
+
+		c, m, y, k = self.cyan, self.magenta, self.yellow, self.black
+
+		r = 1 - min(1, c * (1 - k) + k)
+		g = 1 - min(1, m * (1 - k) + k)
+		b = 1 - min(1, y * (1 - k) + k)
+
+		return SRGBColor(
+			red = r,
+			green = g,
+			blue = b,
+			alpha = self.alpha)
+
+	def ascmyk(self) -> 'CMYKColor':
+		""" Get a CMYKColor out of the current object. """
+
+		return self
+
+
+class LABColor(Color):
+	""" A color expressed with its lightness, and coordinates on the
+		A and B axises of the CIELAB colorspace.
+
+		:param lightness: Value for :py:attr:`lightness`.
+		:param a: Value for :py:attr:`a`.
+		:param b: Value for :py:attr:`b`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_lightness', '_a', '_b')
+	_params = ('lightness', 'a', 'b')
+
+	def __init__(self, lightness: float, a: float, b: float,
+		alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._lightness = lightness
+		self._a = a
+		self._b = b
+
+	@property
+	def lightness(self) -> float:
+		""" The CIE lightness (similar to the lightness
+			in the HSL representation) between 0.0 and 1.0. """
+
+		return self._lightness
+
+	@property
+	def a(self) -> float:
+		""" The A axis value in the Lab colorspace. """
+
+		return self._a
+
+	@property
+	def b(self) -> float:
+		""" The B axis value in the Lab colorspace. """
+
+		return self._b
+
+	def aslab(self) -> 'LABColor':
+		""" Get a LABColor out of the current object. """
+
+		return self
+
+	def aslch(self) -> 'LCHColor':
+		""" Get a LCHColor out of the current object. """
+
+		l, a, b = self.lightness, self.a, self.b
+
+		return LCHColor(
+			lightness = l,
+			chroma = _sqrt(a * a + b * b),
+			hue = _RadiansAngle(_atan2(b, a)),
+			alpha = self.alpha)
+
+
+class LCHColor(Color):
+	""" A color expressed using its lightness, chroma and hue within
+		the CIELAB color space.
+
+		:param lightness: Value for :py:attr:`lightness`.
+		:param chroma: Value for :py:attr:`chroma`.
+		:param hue: Value for :py:attr:`hue`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_lightness', '_chroma', '_hue', '_alpha')
+	_params = ('lightness', 'chroma', 'hue')
+
+	def __init__(self, lightness: float, chroma: float, hue: _Angle,
+		alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._lightness = lightness
+		self._chroma = chroma
+		self._hue = hue
+
+	@property
+	def lightness(self) -> float:
+		""" The CIE lightness (similar to the lightness
+			in the HSL representation) between 0.0 and 1.0. """
+
+		return self._lightness
+
+	@property
+	def chroma(self) -> float:
+		""" The chroma, as a positive number theoretically
+			unbounded. """
+
+		return self._chroma
+
+	@property
+	def hue(self) -> _Angle:
+		""" The hue, as an angle. """
+
+		return self._hue
+
+	def aslab(self) -> 'LABColor':
+		""" Get a LABColor out of the current object. """
+
+		l, c, h = self.lightness, self.chroma, self.hue.asradians()
+
+		return LABColor(
+			lightness = l,
+			a = c * _cos(h.radians),
+			b = c * _sin(h.radians),
+			alpha = self.alpha)
+
+	def aslch(self) -> 'LCHColor':
+		""" Get a LCHColor out of the current object. """
+
+		return self
+
+
+class XYZColor(Color):
+	""" A color expressed using its CIEXYZ color space coordinates.
+
+		:param x: Value for :py:attr:`x`.
+		:param y: Value for :py:attr:`y`.
+		:param z: Value for :py:attr:`z`.
+		:param alpha: Value for :py:attr:`alpha`. """
+
+	__slots__ = ('_x', '_y', '_z')
+	_params = ('x', 'y', 'z')
+
+	def __init__(self, x: float, y: float, z: float, alpha: float = 1.0):
+		super().__init__(alpha)
+
+		self._x = x
+		self._y = y
+		self._z = z
+
+	@property
+	def x(self) -> float:
+		""" The CIE X component, between 0.0 and 1.0. """
+
+		return self._x
+
+	@property
+	def y(self) -> float:
+		""" The CIE Y component, between 0.0 and 1.0. """
+
+		return self._y
+
+	@property
+	def z(self) -> float:
+		""" The CIE Z component, between 0.0 and 1.0. """
+
+		return self._z
+
+	def asxyz(self) -> 'XYZColor':
+		""" Get an XYZColor out of the current object. """
+
+		return self
+
+# End of file.
diff --git a/thcolor/_exc.py b/thcolor/errors.py
index f4954d8..9d827b9 100755
--- a/thcolor/_exc.py
+++ b/thcolor/errors.py
@@ -1,9 +1,10 @@
 #!/usr/bin/env python3
-#******************************************************************************
-# Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+#**************************************************************************
+# Copyright (C) 2019-2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
 # This file is part of the thcolor project, which is MIT-licensed.
-#******************************************************************************
-""" Exception definitions, with internal and external exceptions defined. """
+#**************************************************************************
+""" Exception definitions, with internal and external exceptions
+	defined. """
 
 __all__ = ["ColorExpressionDecodingError",
 	"NotEnoughArgumentsError", "TooManyArgumentsError",
@@ -16,15 +17,15 @@ __all__ = ["ColorExpressionDecodingError",
 class ColorExpressionDecodingError(Exception):
 	""" A color decoding error has occurred on the text. """
 
-	def __init__(self, text, column = None, func = None):
+	def __init__(self, text, column=None, func=None):
 		try:
 			self._column = column
 			assert self._column >= 0
-		except:
+		except AssertionError:
 			self._column = None
 
-		self._func = str(func)
-		self._text = str(text)
+		self._func = str(func) if func else None
+		self._text = str(text) if text else ""
 
 	def __str__(self):
 		msg = ""
@@ -49,8 +50,8 @@ class ColorExpressionDecodingError(Exception):
 	@property
 	def column(self):
 		""" Column of the expression at which the exception has occurred,
-			``None`` if the error has occurred on an unknown column or on the
-			whole exception. """
+			``None`` if the error has occurred on an unknown column or on
+			the whole exception. """
 
 		return self._column
 
@@ -59,7 +60,8 @@ class ColorExpressionDecodingError(Exception):
 		""" Function name we were calling when the error has occurred,
 			either on arguments decoding or erroneous argument type or
 			value, ``None`` if the context is unknown or the error hasn't
-			occurred while calling a function or decoding its arguments. """
+			occurred while calling a function or decoding its
+			arguments. """
 
 		return self._func
 
@@ -70,7 +72,7 @@ class ColorExpressionDecodingError(Exception):
 class NotEnoughArgumentsError(Exception):
 	""" Not enough arguments. """
 
-	def __init__(self, count, name = None):
+	def __init__(self, count, name=None):
 		self._name = name
 		self._count = count
 
@@ -86,10 +88,11 @@ class NotEnoughArgumentsError(Exception):
 	def count(self):
 		return self._count
 
+
 class TooManyArgumentsError(Exception):
 	""" Too many arguments. """
 
-	def __init__(self, count, name = None):
+	def __init__(self, count, name=None):
 		self._name = name
 		self._count = count
 
@@ -105,10 +108,11 @@ class TooManyArgumentsError(Exception):
 	def count(self):
 		return self._count
 
+
 class InvalidArgumentTypeError(Exception):
 	""" Invalid argument type. """
 
-	def __init__(self, index, expected, got, name = None):
+	def __init__(self, index, expected, got, name=None):
 		self._name = name
 		self._index = index
 		self._expected = expected
@@ -134,10 +138,11 @@ class InvalidArgumentTypeError(Exception):
 	def got(self):
 		return self._got
 
+
 class InvalidArgumentValueError(Exception):
 	""" Invalid argument value. """
 
-	def __init__(self, index, text, name = None):
+	def __init__(self, index, text, name=None):
 		self._name = name
 		self._index = index
 		self._text = text
@@ -158,4 +163,5 @@ class InvalidArgumentValueError(Exception):
 	def text(self):
 		return self._text
 
+
 # End of file.
diff --git a/thcolor/reference.py b/thcolor/reference.py
new file mode 100644
index 0000000..e214d3b
--- /dev/null
+++ b/thcolor/reference.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+#**************************************************************************
+# Copyright (C) 2019-2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+# This file is part of the thcolor project, which is MIT-licensed.
+#**************************************************************************
+""" Function and data reference. """
+
+# ---
+# The reference type.
+# ---
+
+class _ReferenceType(type):
+	""" The reference type. """
+
+	def __new__(cls, clsname, superclasses, attributedict):
+		return super().__new__(cls, clsname, superclasses, attributedict)
+
+class Reference(metaclass = _ReferenceType):
+	""" A function and data reference. """
+
+	pass
+
+# End of file.
diff --git a/thcolor/syntax/__init__.py b/thcolor/syntax/__init__.py
new file mode 100644
index 0000000..2c46bbb
--- /dev/null
+++ b/thcolor/syntax/__init__.py
@@ -0,0 +1,338 @@
+#!/usr/bin/env python3
+#**************************************************************************
+# Copyright (C) 2019 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+# This file is part of the thcolor project, which is MIT-licensed.
+#**************************************************************************
+""" Syntax elements for the reference. """
+
+from inspect import getfullargspec as _getfullargspec
+
+__all__ = ["number", "percentage", "angle", "color"]
+
+# ---
+# Syntax elements.
+# ---
+
+class _base_type(type):
+	""" The metaclass for all types used below. """
+
+	def __new__(mcls, name, bases, attrs):
+		return super().__new__(mcls, name, bases, attrs)
+
+	def __init__(self, name, bases, attrs):
+		self.__name = name
+
+	def __contains__(self, other):
+		return self if other == self else None
+
+	def __or__(self, other):
+		return _type_or(self, other)
+
+	def __repr__(self):
+		return f"<class {repr(self.__name)}>"
+
+	def __str__(self):
+		return self.__name
+
+
+class _type_or(metaclass=_base_type):
+	""" A type or another. """
+
+	def __init__(self, type1, type2):
+		self._type1 = type1
+		self._type2 = type2
+
+	@property
+	def type1(self):
+		return self._type1
+
+	@property
+	def type2(self):
+		return self._type2
+
+	def __repr__(self):
+		return f"{repr(self._type1)} | {repr(self._type2)}"
+
+	def __str__(self):
+		return f"{self._type1} or {self._type2}"
+
+	def __or__(self, other):
+		return _type_or(self, other)
+
+	def __contains__(self, other):
+		return other in self._type1 or other in self._type2
+
+
+class number(metaclass=_base_type):
+	""" Syntaxical element for expression decoding, representing
+		a number, integer or decimal, positive or negative.
+
+		This element is usually used to represent a byte value,
+		a factor (usually from 0.0 to 1.0), a color or an angle
+		in degrees. """
+
+	def __init__(self, value):
+		if   type(value) == str:
+			self._strvalue = value
+			self._value = float(value)
+		else:
+			self._value = float(value)
+			if self._value == int(self._value):
+				self._strvalue = str(int(self._value))
+			else:
+				self._strvalue = str(value)
+
+	def __str__(self):
+		return self._strvalue
+
+	@property
+	def value(self):
+		return self._value
+
+	def to_byte(self):
+		""" Make a byte (from 0 to 255) out of the number. """
+
+		try:
+			value = int(self._value)
+
+			assert value == self._value
+			assert 0 <= value < 256
+		except (TypeError, ValueError, AssertionError):
+			raise ValueError("unsuitable value for byte conversion: "
+				f"{repr(self._value)}")
+
+		return value
+
+	def to_factor(self, min=0.0, max=1.0):
+		""" Make a factor (usually from 0.0 to 1.0) out of the
+			number. """
+
+		if (min is not None and self._value < min) \
+		or (max is not None and self._value > max):
+			if   max is None:
+				msg = f"above {min}"
+			elif min is None:
+				msg = f"under {max}"
+			else:
+				msg = f"between {min} and {max}"
+
+			raise ValueError(f"expected a value {msg}, got "
+				f"{self._value}")
+
+		try:
+			assert 0.0 <= self._value <= 1.0
+		except AssertionError:
+			raise ValueError("expected a value between 0.0 and 1.0, "
+				f"got {self._value}")
+
+		return self._value
+
+	def to_hue(self):
+		""" Make an angle in degrees out of the number. """
+
+		return _Angle(_Angle.Type.DEG, self._value)
+
+class percentage(metaclass=_base_type):
+	""" Syntaxical element for expression decoding, representing
+		a percentage (number followed by a '%' sign).
+
+		This element is usually used to represent a factor (usually
+		from 0% to 100%) or anything that can be factored such as a
+		byte value (where 0% represents 0 and 100% represents 255). """
+
+	def __init__(self, value):
+		self._value = value
+
+		if value < 0:
+			value = 0
+
+		# value can actually be more than 100.
+
+	def __repr__(self):
+		return f"{self._value} %"
+
+	def to_factor(self, min=0.0, max=1.0):
+		""" Make a factor (usually from 0.0 to 1.0) out of the
+			number. """
+
+		value = self._value / 100
+		if (min is not None and value < min) \
+		or (max is not None and value > max):
+			if   max is None:
+				msg = f"above {min * 100}%"
+			elif min is None:
+				msg = f"under {max * 100}%"
+			else:
+				msg = f"between {min * 100}% and {max * 100}%"
+
+			raise ValueError(f"expected a percentage {msg}, "
+				f"got {self._value}%")
+
+		return value
+
+	def to_byte(self):
+		""" Make a byte (from 0 to 255) out of the number. """
+
+		if  self._value < 0:
+			self._value = 0
+		if  self._value > 100:
+			self._value = 100
+
+		return int(min(self._value / 100, 1.0) * 255)
+
+class angle(metaclass=_base_type):
+	""" Syntaxical element for expression decoding, representing
+		an angle (a number followed by an angle unit: degrees,
+		gradiants, radiants or turns). """
+
+	def __init__(self, value):
+		if not isinstance(value, _Angle):
+			raise TypeError("expected an Angle instance")
+
+		self._value = value
+
+	def __repr__(self):
+		return repr(self._value)
+
+	def to_hue(self):
+		""" Get the :class:`thcolor.Angle` object. """
+
+		return self._value
+
+class color(metaclass=_base_type):
+	""" Syntaxical element for expression decoding, representing
+		a color using several methods:
+
+		- a hexadecimal code preceeded by a '#', e.g. "#123ABC".
+		- a natural color (see
+			`NCol <https://www.w3schools.com/colors/colors_ncol.asp>`_).
+		- a color name as defined by a :class:`Reference`.
+		- a legacy color name using the legacy color algorithm (or
+			'Netscape' color algorithm). """
+
+	def __init__(self, value):
+		if not isinstance(value, _get_color_class()):
+			raise ValueError("expected a Color instance")
+
+		self._value = value
+
+	def __repr__(self):
+		return repr(self._value)
+
+	def to_color(self):
+		""" Get the :class:`thcolor.Color` object. """
+
+		return self._value
+
+def alias(*names, arg_order=None):
+	""" Decorator for aliasing with another name. Defines a lot, you
+		know. """
+
+	def _decorator(func):
+		nonlocal arg_order
+
+		if not hasattr(func, '_ref_aliases'):
+			func._ref_aliases = ()
+
+		for name in names:
+			if arg_order is None:
+				fn = func
+			else:
+				# First of all, convert the list into a list of
+				# integers going from 0 onwards (instead of anything
+				# else that's there).
+
+				def remake_order(l):
+					class alias_arg:
+						def __init__(self, obj):
+							self.obj = obj
+
+						def __lt__(self, other):
+							return self.obj < other
+
+						def __le__(self, other):
+							return self.obj <= other
+
+						def __eq__(self, other):
+							return self.obj == other
+
+						def __ne__(self, other):
+							return self.obj != other
+
+						def __gt__(self, other):
+							return self.obj > other
+
+						def __ge__(self, other):
+							return self.obj == other
+
+					lst = tuple(alias_arg(o) for o in l)
+					srt = sorted(lst)
+					lst = tuple(next(i for i, m in enumerate(srt)
+						if m is o) for o in lst)
+
+					return lst
+
+				def _reorder(lst, order):
+					t = type(lst)
+					e = list(lst[len(order):])
+					lst = list(lst[:len(order)])
+
+					for i in range(len(order) - 1, -1, -1):
+						e.insert(0, lst[order.index(i)])
+
+					return t(e)
+
+				arg_order = remake_order(arg_order)
+
+				# Then check if the function has that many positional
+				# and keyword arguments.
+
+				args, *_ = _getfullargspec(func)
+				if len(arg_order) > len(args):
+					raise ValueError("argument order length "
+						f"{len(arg_order)} is more than arguments "
+						f"count {len(args)}")
+
+				# Make the fnclass that serves as an
+				# intermediate and also give the modified function
+				# prototype.
+
+				class fnclass:
+					def __init__(self, func, arg_order):
+						self._func = func
+						self._argo = arg_order
+
+					def __call__(self, *args, **kwargs):
+						# This line supposes that the number of
+						# positional arguments is at least.
+
+						args = _reorder(args, self._argo)
+						return self._func(*args, **kwargs)
+
+				# Make the above functions think this is a real
+				# function with some reverted arguments (now that's
+				# the hardest part…).
+
+				class codeclass:
+					def __init__(self, code):
+						self._code = code
+
+					def __getattr__(self, attr):
+						return getattr(self._code, attr)
+
+				fn = fnclass(func, arg_order)
+				co = codeclass(func.__code__)
+
+				co.co_varnames = _reorder(co.co_varnames, arg_order)
+
+				fn.__name__ = func.__name__
+				fn.__qualname__ = func.__qualname__
+				fn.__code__ = co
+				fn.__annotations__ = func.__annotations__
+
+			func._ref_aliases += ((name, fn),)
+			return func
+
+	return _decorator
+
+# End of file.
diff --git a/thcolor/version.py b/thcolor/version.py
new file mode 100755
index 0000000..b51eff8
--- /dev/null
+++ b/thcolor/version.py
@@ -0,0 +1,12 @@
+#!/usr/bin/env python3
+#**************************************************************************
+# Copyright (C) 2021 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
+# This file is part of the thcolor project, which is MIT-licensed.
+#**************************************************************************
+""" Version definition for the thcolor module. """
+
+__all__ = ["version"]
+
+version = "0.3.1"
+
+# End of file.
author	Thomas Touhey <thomas@touhey.fr>	2021-09-11 21:09:06 +0200
committer	Thomas Touhey <thomas@touhey.fr>	2021-09-11 21:09:06 +0200
commit	5f54b6757abee47ee883d353e4aeda9c56dd6c89 (patch)
tree	20bff9751f36f0bb5d4504f1961e51d033add177
parent	b3edd31df8c96035d70c0216e444d6dd9951699f (diff)