mirror of https://github.com/python/cpython
80 lines
2.6 KiB
Python
80 lines
2.6 KiB
Python
from pygments.lexer import RegexLexer, bygroups, include
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from pygments.token import Comment, Keyword, Name, Operator, Punctuation, Text
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class PEGLexer(RegexLexer):
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"""Pygments Lexer for PEG grammar (.gram) files
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This lexer strips the following elements from the grammar:
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- Meta-tags
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- Variable assignments
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- Actions
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- Lookaheads
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- Rule types
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- Rule options
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- Rules named `invalid_*` or `incorrect_*`
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"""
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name = "PEG"
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aliases = ["peg"]
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filenames = ["*.gram"]
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_name = r"([^\W\d]\w*)"
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_text_ws = r"(\s*)"
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tokens = {
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"ws": [(r"\n", Text), (r"\s+", Text), (r"#.*$", Comment.Singleline),],
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"lookaheads": [
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# Forced tokens
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(r"(&&)(?=\w+\s?)", bygroups(None)),
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(r"(&&)(?='.+'\s?)", bygroups(None)),
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(r'(&&)(?=".+"\s?)', bygroups(None)),
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(r"(&&)(?=\(.+\)\s?)", bygroups(None)),
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(r"(?<=\|\s)(&\w+\s?)", bygroups(None)),
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(r"(?<=\|\s)(&'.+'\s?)", bygroups(None)),
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(r'(?<=\|\s)(&".+"\s?)', bygroups(None)),
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(r"(?<=\|\s)(&\(.+\)\s?)", bygroups(None)),
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],
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"metas": [
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(r"(@\w+ '''(.|\n)+?''')", bygroups(None)),
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(r"^(@.*)$", bygroups(None)),
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],
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"actions": [
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(r"{(.|\n)+?}", bygroups(None)),
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],
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"strings": [
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(r"'\w+?'", Keyword),
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(r'"\w+?"', Keyword),
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(r"'\W+?'", Text),
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(r'"\W+?"', Text),
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],
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"variables": [
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(_name + _text_ws + "(=)", bygroups(None, None, None),),
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(_name + _text_ws + r"(\[[\w\d_\*]+?\])" + _text_ws + "(=)", bygroups(None, None, None, None, None),),
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],
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"invalids": [
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(r"^(\s+\|\s+.*invalid_\w+.*\n)", bygroups(None)),
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(r"^(\s+\|\s+.*incorrect_\w+.*\n)", bygroups(None)),
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(r"^(#.*invalid syntax.*(?:.|\n)*)", bygroups(None),),
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],
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"root": [
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include("invalids"),
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include("ws"),
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include("lookaheads"),
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include("metas"),
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include("actions"),
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include("strings"),
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include("variables"),
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(r"\b(?!(NULL|EXTRA))([A-Z_]+)\b\s*(?!\()", Text,),
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(
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r"^\s*" + _name + r"\s*" + r"(\[.*\])?" + r"\s*" + r"(\(.+\))?" + r"\s*(:)",
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bygroups(Name.Function, None, None, Punctuation),
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),
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(_name, Name.Function),
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(r"[\||\.|\+|\*|\?]", Operator),
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(r"{|}|\(|\)|\[|\]", Punctuation),
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(r".", Text),
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],
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}
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