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"""
pygments.lexers.grammar_notation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lexers for grammar notations like BNF.
:copyright: Copyright 2006-2025 by the Pygments team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
from pygments.lexer import RegexLexer, bygroups, include, this, using, words
from pygments.token import Comment, Keyword, Literal, Name, Number, \
Operator, Punctuation, String, Text, Whitespace
__all__ = ['BnfLexer', 'AbnfLexer', 'JsgfLexer', 'PegLexer']
class BnfLexer(RegexLexer):
"""
This lexer is for grammar notations which are similar to
original BNF.
In order to maximize a number of targets of this lexer,
let's decide some designs:
* We don't distinguish `Terminal Symbol`.
* We do assume that `NonTerminal Symbol` are always enclosed
with arrow brackets.
* We do assume that `NonTerminal Symbol` may include
any printable characters except arrow brackets and ASCII 0x20.
This assumption is for `RBNF <http://www.rfc-base.org/txt/rfc-5511.txt>`_.
* We do assume that target notation doesn't support comment.
* We don't distinguish any operators and punctuation except
`::=`.
Though these decision making might cause too minimal highlighting
and you might be disappointed, but it is reasonable for us.
"""
name = 'BNF'
aliases = ['bnf']
filenames = ['*.bnf']
mimetypes = ['text/x-bnf']
url = 'https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form'
version_added = '2.1'
tokens = {
'root': [
(r'(<)([ -;=?-~]+)(>)',
bygroups(Punctuation, Name.Class, Punctuation)),
# an only operator
(r'::=', Operator),
# fallback
(r'[^<>:]+', Text), # for performance
(r'.', Text),
],
}
class AbnfLexer(RegexLexer):
"""
Lexer for IETF 7405 ABNF.
(Updates `5234 <http://www.ietf.org/rfc/rfc5234.txt>`_) grammars.
"""
name = 'ABNF'
url = 'http://www.ietf.org/rfc/rfc7405.txt'
aliases = ['abnf']
filenames = ['*.abnf']
mimetypes = ['text/x-abnf']
version_added = '2.1'
_core_rules = (
'ALPHA', 'BIT', 'CHAR', 'CR', 'CRLF', 'CTL', 'DIGIT',
'DQUOTE', 'HEXDIG', 'HTAB', 'LF', 'LWSP', 'OCTET',
'SP', 'VCHAR', 'WSP')
tokens = {
'root': [
# comment
(r';.*$', Comment.Single),
# quoted
# double quote itself in this state, it is as '%x22'.
(r'(%[si])?"[^"]*"', Literal),
# binary (but i have never seen...)
(r'%b[01]+\-[01]+\b', Literal), # range
(r'%b[01]+(\.[01]+)*\b', Literal), # concat
# decimal
(r'%d[0-9]+\-[0-9]+\b', Literal), # range
(r'%d[0-9]+(\.[0-9]+)*\b', Literal), # concat
# hexadecimal
(r'%x[0-9a-fA-F]+\-[0-9a-fA-F]+\b', Literal), # range
(r'%x[0-9a-fA-F]+(\.[0-9a-fA-F]+)*\b', Literal), # concat
# repetition (<a>*<b>element) including nRule
(r'\b[0-9]+\*[0-9]+', Operator),
(r'\b[0-9]+\*', Operator),
(r'\b[0-9]+', Operator),
(r'\*', Operator),
# Strictly speaking, these are not keyword but
# are called `Core Rule'.
(words(_core_rules, suffix=r'\b'), Keyword),
# nonterminals (ALPHA *(ALPHA / DIGIT / "-"))
(r'[a-zA-Z][a-zA-Z0-9-]*\b', Name.Class),
# operators
(r'(=/|=|/)', Operator),
# punctuation
(r'[\[\]()]', Punctuation),
# fallback
(r'\s+', Whitespace),
(r'.', Text),
],
}
class JsgfLexer(RegexLexer):
"""
For JSpeech Grammar Format grammars.
"""
name = 'JSGF'
url = 'https://www.w3.org/TR/jsgf/'
aliases = ['jsgf']
filenames = ['*.jsgf']
mimetypes = ['application/jsgf', 'application/x-jsgf', 'text/jsgf']
version_added = '2.2'
tokens = {
'root': [
include('comments'),
include('non-comments'),
],
'comments': [
(r'/\*\*(?!/)', Comment.Multiline, 'documentation comment'),
(r'/\*[\w\W]*?\*/', Comment.Multiline),
(r'//.*$', Comment.Single),
],
'non-comments': [
(r'\A#JSGF[^;]*', Comment.Preproc),
(r'\s+', Whitespace),
(r';', Punctuation),
(r'[=|()\[\]*+]', Operator),
(r'/[^/]+/', Number.Float),
(r'"', String.Double, 'string'),
(r'\{', String.Other, 'tag'),
(words(('import', 'public'), suffix=r'\b'), Keyword.Reserved),
(r'grammar\b', Keyword.Reserved, 'grammar name'),
(r'(<)(NULL|VOID)(>)',
bygroups(Punctuation, Name.Builtin, Punctuation)),
(r'<', Punctuation, 'rulename'),
(r'\w+|[^\s;=|()\[\]*+/"{<\w]+', Text),
],
'string': [
(r'"', String.Double, '#pop'),
(r'\\.', String.Escape),
(r'[^\\"]+', String.Double),
],
'tag': [
(r'\}', String.Other, '#pop'),
(r'\\.', String.Escape),
(r'[^\\}]+', String.Other),
],
'grammar name': [
(r';', Punctuation, '#pop'),
(r'\s+', Whitespace),
(r'\.', Punctuation),
(r'[^;\s.]+', Name.Namespace),
],
'rulename': [
(r'>', Punctuation, '#pop'),
(r'\*', Punctuation),
(r'\s+', Whitespace),
(r'([^.>]+)(\s*)(\.)', bygroups(Name.Namespace, Text, Punctuation)),
(r'[^.>]+', Name.Constant),
],
'documentation comment': [
(r'\*/', Comment.Multiline, '#pop'),
(r'^(\s*)(\*?)(\s*)(@(?:example|see))(\s+)'
r'([\w\W]*?(?=(?:^\s*\*?\s*@|\*/)))',
bygroups(Whitespace, Comment.Multiline, Whitespace, Comment.Special,
Whitespace, using(this, state='example'))),
(r'(^\s*\*?\s*)(@\S*)',
bygroups(Comment.Multiline, Comment.Special)),
(r'[^*\n@]+|\w|\W', Comment.Multiline),
],
'example': [
(r'(\n\s*)(\*)', bygroups(Whitespace, Comment.Multiline)),
include('non-comments'),
(r'.', Comment.Multiline),
],
}
class PegLexer(RegexLexer):
"""
This lexer is for Parsing Expression Grammars (PEG).
Various implementations of PEG have made different decisions
regarding the syntax, so let's try to be accommodating:
* `<-`, `←`, `:`, and `=` are all accepted as rule operators.
* Both `|` and `/` are choice operators.
* `^`, `↑`, and `~` are cut operators.
* A single `a-z` character immediately before a string, or
multiple `a-z` characters following a string, are part of the
string (e.g., `r"..."` or `"..."ilmsuxa`).
"""
name = 'PEG'
url = 'https://bford.info/pub/lang/peg.pdf'
aliases = ['peg']
filenames = ['*.peg']
mimetypes = ['text/x-peg']
version_added = '2.6'
tokens = {
'root': [
# Comments
(r'#.*$', Comment.Single),
# All operators
(r'<-|[←:=/|&!?*+^↑~]', Operator),
# Other punctuation
(r'[()]', Punctuation),
# Keywords
(r'\.', Keyword),
# Character classes
(r'(\[)([^\]]*(?:\\.[^\]\\]*)*)(\])',
bygroups(Punctuation, String, Punctuation)),
# Single and double quoted strings (with optional modifiers)
(r'[a-z]?"[^"\\]*(?:\\.[^"\\]*)*"[a-z]*', String.Double),
(r"[a-z]?'[^'\\]*(?:\\.[^'\\]*)*'[a-z]*", String.Single),
# Nonterminals are not whitespace, operators, or punctuation
(r'[^\s<←:=/|&!?*+\^↑~()\[\]"\'#]+', Name.Class),
# Fallback
(r'.', Text),
],
}
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