Lib/keyword.py

Source:

cpython 3.14 @ ab2d84fe1023/Lib/keyword.py ↗

keyword exposes the canonical lists of Python hard keywords (kwlist) and soft keywords (softkwlist). It is auto-generated from Tools/build/generate_token.py and is used by tokenize, ast, IDE tooling, and dis.

Map

Lines	Symbol	Role
1-10	Module header	Auto-generated notice
11-50	kwlist, softkwlist	Sorted lists of keyword strings
51-56	iskeyword, issoftkeyword	Lookup functions

Reading

kwlist (hard keywords)

Hard keywords are reserved tokens that the parser always treats as keywords, regardless of context.

# CPython: Lib/keyword.py:15 kwlist
kwlist = [
    'False',
    'None',
    'True',
    'and',
    'as',
    'assert',
    'async',
    'await',
    'break',
    'class',
    'continue',
    'def',
    'del',
    'elif',
    'else',
    'except',
    'finally',
    'for',
    'from',
    'global',
    'if',
    'import',
    'in',
    'is',
    'lambda',
    'nonlocal',
    'not',
    'or',
    'pass',
    'raise',
    'return',
    'try',
    'while',
    'with',
    'yield',
]

softkwlist (soft keywords, Python 3.12+)

Soft keywords are identifiers that have special meaning only in specific syntactic positions. They can be used as variable names outside those positions.

# CPython: Lib/keyword.py:54 softkwlist
softkwlist = [
    '_',
    'case',
    'match',
    'type',
]

match, case, and type became soft keywords when pattern matching (PEP 634) and the type statement (PEP 695) were introduced.

iskeyword and issoftkeyword

# CPython: Lib/keyword.py:58 iskeyword
iskeyword = frozenset(kwlist).__contains__
issoftkeyword = frozenset(softkwlist).__contains__

Both are implemented as frozenset.__contains__ for O(1) lookup.

gopy notes

Status: kwlist is already effectively ported because the parser in gopy uses the same keyword set. The keyword module just needs to expose kwlist, softkwlist, iskeyword, and issoftkeyword as Python-visible names via module/keyword/. The lists must match the parser's token tables exactly.