root/misc/syntax/bnf.syntax

/*   */

# BNF family (BNF, EBNF, ABNF, WBNF etc.) Syntax Highlighting Definition
# Version 3.0.1 2026-03-25
# See updates and changelog at https://github.com/jip/syntax-highlighting
#
# Backus-Naur form (BNF) is a notation technique for context-free grammars
#
# This file is part of GNU Midnight Commander
# https://midnight-commander.org/
#
# SPDX-FileCopyrightText: 2026 Igor Zhuravlov <zhuravlov.ip@ya.ru>
# SPDX-License-Identifier: GPL-3.0-or-later
 
# for the default (lightgray on blue)
define _alerthi lightgray red
define _alertmi gray yellow
define _alertlo gray cyan
define _assign  white
define _comb    yellow
define _comment brown
define _esc     brightgreen
define _group   brightcyan
define _lbl     lightgray blue underline
define _num     brightgreen
define _oper    yellow
define _sep     brightmagenta
define _special gray
define _str     green
define _var     lightgray
 
context default
    # labels
    keyword \{abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_\}\[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._\]: _lbl
    # nonterminals
    keyword <\{abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_\}\[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._\]> _var
    keyword \{abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_\}\[abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._\] _var
    # decimal integer numbers
    keyword wholeleft 0 _num
    keyword wholeleft \{123456789_\}\[0123456789_\] _num
    keyword wholeleft -\{123456789_\}\[0123456789_\] _num
    # repeaters (EBNF)
    keyword (/ _group
    keyword /) _group
    keyword (: _group
    keyword :) _group
    # exclude from highlighting
    keyword ::== lightgray blue
    # assignments
    keyword :≡ _assign
    keyword :== _assign
    keyword := _assign
    keyword ::= _assign
    keyword :: _assign
    keyword : _assign
    keyword => _assign
    keyword = _assign
    keyword <- _assign
    keyword -> _assign
    keyword <= _assign
    keyword ← _assign
    keyword → _assign
    keyword ⇐ _assign
    keyword ⇒ _assign
    keyword ≜ _assign
    # combinators
    keyword | _comb
    keyword / _comb
    keyword \\ _comb
    keyword - _comb
    keyword , _comb
    # operators
    keyword ! _oper
    keyword # _oper
    keyword $ _oper
#    keyword % _oper
    keyword & _oper
    keyword \* _oper
    keyword \+ _oper
    keyword ? _oper
    keyword @ _oper
    keyword ^ _oper
    keyword ~ _oper
    # grouping
    keyword ( _group
    keyword ) _group
    keyword < _group
    keyword > _group
    keyword [ _group
    keyword ] _group
    keyword { _group
    keyword } _group
    # concatenator,separator,terminator
    keyword \{.;\} _sep
 
# strings
 
context ' ' _str
    keyword \\' _esc
    keyword \\\\ _esc
    keyword \\\{abtnvfr\} _esc
    keyword \\x\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
    keyword \\u\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
    keyword \\U\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
 
context " " _str
    keyword \\" _esc
    keyword \\\\ _esc
    keyword \\\{abtnvfr\} _esc
    keyword \\x\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
    keyword \\u\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
    keyword \\U\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\}\{0123456789abcdefABCDEF\} _esc
 
# special sequence
 
context ` ` _special
    keyword \\` _special
 
# comments
 
context % % _comment
    keyword \\% _comment
    keyword whole BUG        _alerthi
    keyword whole DEPRECATED _alertmi
    keyword whole FIXME      _alerthi
    keyword whole NOTE       _alertlo
    keyword whole TEST       _alertlo
    keyword whole TODO       _alertmi
    keyword whole WARN       _alertmi
    spellcheck

/*   */