Commit: runtime(python): Highlight built-in constants in Python

[Christian Brabandt]

runtime(python): Highlight built-in constants in Python

Commit: https://github.com/vim/vim/commit/632fd8bb968b029d0a7c40a00101008ea5200b91
Author: Rob B <git...@0x7e.net>
Date: Mon Jan 26 18:52:04 2026 +0000

runtime(python): Highlight built-in constants in Python

Also add syntax tests for those newly constants.

closes: #17788
closes: #18922

Signed-off-by: Rob B <git...@0x7e.net>
Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 501dd9457..cc41a774a 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt* For Vim version 9.1. Last change: 2026 Jan 25
+*syntax.txt* For Vim version 9.1. Last change: 2026 Jan 26


VIM REFERENCE MANUAL by Bram Moolenaar
@@ -3223,7 +3223,7 @@ Pascal. Use this if you don't use assembly and Pascal: >

PYTHON *python.vim* *ft-python-syntax*

-There are six options to control Python syntax highlighting.
+There are seven options to control Python syntax highlighting.

For highlighted numbers: >
:let python_no_number_highlight = 1
@@ -3243,10 +3243,13 @@ The first option implies the second one.
For highlighted trailing whitespace and mix of spaces and tabs: >
:let python_space_error_highlight = 1

+For highlighted built-in constants distinguished from other keywords:
+ :let python_constant_highlight = 1
+
If you want all possible Python highlighting: >
:let python_highlight_all = 1
-This has the same effect as setting python_space_error_highlight and
-unsetting all the other ones.
+This has the same effect as setting python_space_error_highlight,
+python_constant_highlight and unsetting all the other ones.

If you use Python 2 or straddling code (Python 2 and 3 compatible),
you can enforce the use of an older syntax file with support for
diff --git a/runtime/syntax/python.vim b/runtime/syntax/python.vim
index 301fb8480..456a9825a 100644
--- a/runtime/syntax/python.vim
+++ b/runtime/syntax/python.vim
@@ -4,6 +4,7 @@
" Last Change: 2025 Sep 08
" 2025 Sep 25 by Vim Project: fix wrong type highlighting #18394
" 2025 Dec 03 by Vim Project: highlight t-strings #18679
+" 2026 Jan 26 by Vim Project: highlight constants #18922
" Credits: Neil Schemenauer <n...@python.ca>
" Dmitry Vasiliev
" Rob B
@@ -34,6 +35,7 @@
" let python_no_exception_highlight = 1
" let python_no_number_highlight = 1
" let python_space_error_highlight = 1
+" let python_constant_highlight = 1
"
" All the options above can be switched on together.
"
@@ -85,6 +87,7 @@ if exists("python_highlight_all")
unlet python_no_number_highlight
endif
let python_space_error_highlight = 1
+ let python_constant_highlight = 1
endif

" Keep Python keywords in alphabetical order inside groups for easy
@@ -97,7 +100,8 @@ endif
"
" python3 -c 'import keyword, pprint; pprint.pprint(keyword.kwlist + keyword.softkwlist, compact=True)'
"
-syn keyword pythonStatement False None True
+syn keyword pythonBoolean False True
+syn keyword pythonConstant None
syn keyword pythonStatement as assert break continue del global
syn keyword pythonStatement lambda nonlocal pass return with yield
syn keyword pythonStatement class nextgroup=pythonClass skipwhite
@@ -296,8 +300,8 @@ endif
if !exists("python_no_builtin_highlight")
" built-in constants
" 'False', 'True', and 'None' are also reserved words in Python 3
- syn keyword pythonBuiltin False True None
- syn keyword pythonBuiltin NotImplemented Ellipsis __debug__
+ syn keyword pythonBoolean False True
+ syn keyword pythonConstant None NotImplemented Ellipsis __debug__
" constants added by the `site` module
syn keyword pythonBuiltin quit exit copyright credits license
" built-in functions
@@ -391,6 +395,8 @@ endif
syn sync match pythonSync grouphere NONE "^\%(def\|class\|async\s\+def\)\s\+\h\w*\s*[(:]"

" The default highlight links. Can be overridden later.
+hi def link pythonBoolean Statement
+hi def link pythonConstant Statement
hi def link pythonStatement Statement
hi def link pythonConditional Conditional
hi def link pythonRepeat Repeat
@@ -421,6 +427,8 @@ if !exists("python_no_number_highlight")
hi def link pythonNumber Number
endif
if !exists("python_no_builtin_highlight")
+ hi! def link pythonBoolean Function
+ hi! def link pythonConstant Function
hi def link pythonBuiltin Function
hi def link pythonEllipsis pythonBuiltin
endif
@@ -434,6 +442,10 @@ if !exists("python_no_doctest_highlight")
hi def link pythonDoctest Special
hi def link pythonDoctestValue Define
endif
+if exists("python_constant_highlight")
+ hi! def link pythonBoolean Boolean
+ hi! def link pythonConstant Constant
+endif

let b:current_syntax = "python"

diff --git a/runtime/syntax/testdir/dumps/python_constants_builtin_default_00.dump b/runtime/syntax/testdir/dumps/python_constants_builtin_default_00.dump
new file mode 100644
index 000000000..bbee183df
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/python_constants_builtin_default_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0| |B|u|i|l|t|-|i|n| |C|o|n|s|t|a|n|t|s| +0#0000000&@54
+|#+0#0000e05&| |h|t@1|p|s|:|/@1|d|o|c|s|.|p|y|t|h|o|n|.|o|r|g|/|3|/|l|i|b|r|a|r|y|/|c|o|n|s|t|a|n|t|s|.|h|t|m|l| +0#0000000&@24
+@75
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t| |g|:|p|y|t|h|o|n|_|c|o|n|s|t|a|n|t|_|h|i|g|h|l|i|g|h|t| +0#0000000&@24
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t| |g|:|p|y|t|h|o|n|_|n|o|_|b|u|i|l|t|i|n|_|h|i|g|h|l|i|g|h|t| +0#0000000&@22
+|t|e|s|t| |=| |F+0#00e0e07&|a|l|s|e| +0#0000000&@62
+|t|e|s|t| |=| |T+0#00e0e07&|r|u|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#00e0e07&|o|n|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#00e0e07&|o|t|I|m|p|l|e|m|e|n|t|e|d| +0#0000000&@53
+|t|e|s|t| |=| |E+0#00e0e07&|l@1|i|p|s|i|s| +0#0000000&@59
+|t|e|s|t| |=| |_+0#00e0e07&@1|d|e|b|u|g|_@1| +0#0000000&@58
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1|
diff --git a/runtime/syntax/testdir/dumps/python_constants_builtin_highlight_00.dump b/runtime/syntax/testdir/dumps/python_constants_builtin_highlight_00.dump
new file mode 100644
index 000000000..206f673af
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/python_constants_builtin_highlight_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0| |B|u|i|l|t|-|i|n| |C|o|n|s|t|a|n|t|s| +0#0000000&@54
+|#+0#0000e05&| |h|t@1|p|s|:|/@1|d|o|c|s|.|p|y|t|h|o|n|.|o|r|g|/|3|/|l|i|b|r|a|r|y|/|c|o|n|s|t|a|n|t|s|.|h|t|m|l| +0#0000000&@24
+@75
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|p|y|t|h|o|n|_|c|o|n|s|t|a|n|t|_|h|i|g|h|l|i|g|h|t| |=| |1| +0#0000000&@22
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t| |g|:|p|y|t|h|o|n|_|n|o|_|b|u|i|l|t|i|n|_|h|i|g|h|l|i|g|h|t| +0#0000000&@22
+|t|e|s|t| |=| |F+0#e000002&|a|l|s|e| +0#0000000&@62
+|t|e|s|t| |=| |T+0#e000002&|r|u|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#e000002&|o|n|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#e000002&|o|t|I|m|p|l|e|m|e|n|t|e|d| +0#0000000&@53
+|t|e|s|t| |=| |E+0#e000002&|l@1|i|p|s|i|s| +0#0000000&@59
+|t|e|s|t| |=| |_+0#e000002&@1|d|e|b|u|g|_@1| +0#0000000&@58
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1|
diff --git a/runtime/syntax/testdir/dumps/python_constants_keyword_default_00.dump b/runtime/syntax/testdir/dumps/python_constants_keyword_default_00.dump
new file mode 100644
index 000000000..941e69e97
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/python_constants_keyword_default_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0| |B|u|i|l|t|-|i|n| |C|o|n|s|t|a|n|t|s| +0#0000000&@54
+|#+0#0000e05&| |h|t@1|p|s|:|/@1|d|o|c|s|.|p|y|t|h|o|n|.|o|r|g|/|3|/|l|i|b|r|a|r|y|/|c|o|n|s|t|a|n|t|s|.|h|t|m|l| +0#0000000&@24
+@75
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |u|n|l|e|t| |g|:|p|y|t|h|o|n|_|c|o|n|s|t|a|n|t|_|h|i|g|h|l|i|g|h|t| +0#0000000&@24
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|p|y|t|h|o|n|_|n|o|_|b|u|i|l|t|i|n|_|h|i|g|h|l|i|g|h|t| |=| |1| +0#0000000&@20
+|t|e|s|t| |=| |F+0#af5f00255&|a|l|s|e| +0#0000000&@62
+|t|e|s|t| |=| |T+0#af5f00255&|r|u|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#af5f00255&|o|n|e| +0#0000000&@63
+|t|e|s|t| |=| |N|o|t|I|m|p|l|e|m|e|n|t|e|d| @53
+|t|e|s|t| |=| |E|l@1|i|p|s|i|s| @59
+|t|e|s|t| |=| |_@1|d|e|b|u|g|_@1| @58
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1|
diff --git a/runtime/syntax/testdir/dumps/python_constants_keyword_highlight_00.dump b/runtime/syntax/testdir/dumps/python_constants_keyword_highlight_00.dump
new file mode 100644
index 000000000..b73c6ae02
--- /dev/null
+++ b/runtime/syntax/testdir/dumps/python_constants_keyword_highlight_00.dump
@@ -0,0 +1,20 @@
+>#+0#0000e05#ffffff0| |B|u|i|l|t|-|i|n| |C|o|n|s|t|a|n|t|s| +0#0000000&@54
+|#+0#0000e05&| |h|t@1|p|s|:|/@1|d|o|c|s|.|p|y|t|h|o|n|.|o|r|g|/|3|/|l|i|b|r|a|r|y|/|c|o|n|s|t|a|n|t|s|.|h|t|m|l| +0#0000000&@24
+@75
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|p|y|t|h|o|n|_|c|o|n|s|t|a|n|t|_|h|i|g|h|l|i|g|h|t| |=| |1| +0#0000000&@22
+|#+0#0000e05&| |V|I|M|_|T|E|S|T|_|S|E|T|U|P| |l|e|t| |g|:|p|y|t|h|o|n|_|n|o|_|b|u|i|l|t|i|n|_|h|i|g|h|l|i|g|h|t| |=| |1| +0#0000000&@20
+|t|e|s|t| |=| |F+0#e000002&|a|l|s|e| +0#0000000&@62
+|t|e|s|t| |=| |T+0#e000002&|r|u|e| +0#0000000&@63
+|t|e|s|t| |=| |N+0#e000002&|o|n|e| +0#0000000&@63
+|t|e|s|t| |=| |N|o|t|I|m|p|l|e|m|e|n|t|e|d| @53
+|t|e|s|t| |=| |E|l@1|i|p|s|i|s| @59
+|t|e|s|t| |=| |_@1|d|e|b|u|g|_@1| @58
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|1|,|1| @10|A|l@1|
diff --git a/runtime/syntax/testdir/input/python_constants_builtin_default.py b/runtime/syntax/testdir/input/python_constants_builtin_default.py
new file mode 100644
index 000000000..d55e65632
--- /dev/null
+++ b/runtime/syntax/testdir/input/python_constants_builtin_default.py
@@ -0,0 +1,11 @@
+# Built-in Constants
+# https://docs.python.org/3/library/constants.html
+
+# VIM_TEST_SETUP unlet g:python_constant_highlight
+# VIM_TEST_SETUP unlet g:python_no_builtin_highlight
+test = False
+test = True
+test = None
+test = NotImplemented
+test = Ellipsis
+test = __debug__
diff --git a/runtime/syntax/testdir/input/python_constants_builtin_highlight.py b/runtime/syntax/testdir/input/python_constants_builtin_highlight.py
new file mode 100644
index 000000000..e092b186e
--- /dev/null
+++ b/runtime/syntax/testdir/input/python_constants_builtin_highlight.py
@@ -0,0 +1,11 @@
+# Built-in Constants
+# https://docs.python.org/3/library/constants.html
+
+# VIM_TEST_SETUP let g:python_constant_highlight = 1
+# VIM_TEST_SETUP unlet g:python_no_builtin_highlight
+test = False
+test = True
+test = None
+test = NotImplemented
+test = Ellipsis
+test = __debug__
diff --git a/runtime/syntax/testdir/input/python_constants_keyword_default.py b/runtime/syntax/testdir/input/python_constants_keyword_default.py
new file mode 100644
index 000000000..7b3d9c9c6
--- /dev/null
+++ b/runtime/syntax/testdir/input/python_constants_keyword_default.py
@@ -0,0 +1,11 @@
+# Built-in Constants
+# https://docs.python.org/3/library/constants.html
+
+# VIM_TEST_SETUP unlet g:python_constant_highlight
+# VIM_TEST_SETUP let g:python_no_builtin_highlight = 1
+test = False
+test = True
+test = None
+test = NotImplemented
+test = Ellipsis
+test = __debug__
diff --git a/runtime/syntax/testdir/input/python_constants_keyword_highlight.py b/runtime/syntax/testdir/input/python_constants_keyword_highlight.py
new file mode 100644
index 000000000..60f3fb227
--- /dev/null
+++ b/runtime/syntax/testdir/input/python_constants_keyword_highlight.py
@@ -0,0 +1,11 @@
+# Built-in Constants
+# https://docs.python.org/3/library/constants.html
+
+# VIM_TEST_SETUP let g:python_constant_highlight = 1
+# VIM_TEST_SETUP let g:python_no_builtin_highlight = 1
+test = False
+test = True
+test = None
+test = NotImplemented
+test = Ellipsis
+test = __debug__