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from pygments.lexer import RegexLexer, bygroups, include
from pygments.token import Comment, Generic, Keyword, Name, Operator, Punctuation, Text
from sphinx.highlighting import lexers
class PEGLexer(RegexLexer):
"""Pygments Lexer for PEG grammar (.gram) files
This lexer strips the following elements from the grammar:
- Meta-tags
- Variable assignments
- Actions
- Lookaheads
- Rule types
- Rule options
- Rules named `invalid_*` or `incorrect_*`
"""
name = "PEG"
aliases = ["peg"]
filenames = ["*.gram"]
_name = r"([^\W\d]\w*)"
_text_ws = r"(\s*)"
tokens = {
"ws": [(r"\n", Text), (r"\s+", Text), (r"#.*$", Comment.Singleline),],
"lookaheads": [
# Forced tokens
(r"(&&)(?=\w+\s?)", bygroups(None)),
(r"(&&)(?='.+'\s?)", bygroups(None)),
(r'(&&)(?=".+"\s?)', bygroups(None)),
(r"(&&)(?=\(.+\)\s?)", bygroups(None)),
(r"(?<=\|\s)(&\w+\s?)", bygroups(None)),
(r"(?<=\|\s)(&'.+'\s?)", bygroups(None)),
(r'(?<=\|\s)(&".+"\s?)', bygroups(None)),
(r"(?<=\|\s)(&\(.+\)\s?)", bygroups(None)),
],
"metas": [
(r"(@\w+ '''(.|\n)+?''')", bygroups(None)),
(r"^(@.*)$", bygroups(None)),
],
"actions": [
(r"{(.|\n)+?}", bygroups(None)),
],
"strings": [
(r"'\w+?'", Keyword),
(r'"\w+?"', Keyword),
(r"'\W+?'", Text),
(r'"\W+?"', Text),
],
"variables": [
(_name + _text_ws + "(=)", bygroups(None, None, None),),
(_name + _text_ws + r"(\[[\w\d_\*]+?\])" + _text_ws + "(=)", bygroups(None, None, None, None, None),),
],
"invalids": [
(r"^(\s+\|\s+.*invalid_\w+.*\n)", bygroups(None)),
(r"^(\s+\|\s+.*incorrect_\w+.*\n)", bygroups(None)),
(r"^(#.*invalid syntax.*(?:.|\n)*)", bygroups(None),),
],
"root": [
include("invalids"),
include("ws"),
include("lookaheads"),
include("metas"),
include("actions"),
include("strings"),
include("variables"),
(r"\b(?!(NULL|EXTRA))([A-Z_]+)\b\s*(?!\()", Text,),
(
r"^\s*" + _name + r"\s*" + r"(\[.*\])?" + r"\s*" + r"(\(.+\))?" + r"\s*(:)",
bygroups(Name.Function, None, None, Punctuation),
),
(_name, Name.Function),
(r"[\||\.|\+|\*|\?]", Operator),
(r"{|}|\(|\)|\[|\]", Punctuation),
(r".", Text),
],
}
def setup(app):
lexers["peg"] = PEGLexer()
return {"version": "1.0", "parallel_read_safe": True}
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