vis

a vi-like editor based on Plan 9's structural regular expressions
fennel.lua

(1692B)
      1 -- Copyright 2006-2025 Mitchell. See LICENSE.
      2 -- Fennel LPeg lexer.
      3 -- Contributed by Momohime Honda.
      4 
      5 local lexer = require('lexer')
      6 local token, word_match = lexer.token, lexer.word_match
      7 local P, S = lpeg.P, lpeg.S
      8 
      9 local lex = lexer.new('fennel', {inherit = lexer.load('lua')})
     10 
     11 -- Whitespace.
     12 lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
     13 
     14 -- Keywords.
     15 lex:modify_rule('keyword', token(lexer.KEYWORD, word_match{
     16 	'#', '%', '*', '+', '-', '->>', '->', '-?>>', '-?>', '..', '.', '//', '/', ':', '<=', '<', '=',
     17 	'>=', '>', '?.', '^', '~=', 'λ', 'accumulate', 'and', 'band', 'bnot', 'bor', 'bxor', 'collect',
     18 	'comment', 'do', 'doto', 'each', 'eval-compiler', 'fn', 'for', 'global', 'hashfn', 'icollect',
     19 	'if', 'import-macros', 'include', 'lambda', 'length', 'let', 'local', 'lshift', 'lua', 'macro',
     20 	'macrodebug', 'macros', 'match', 'not', 'not=', 'or', 'partial', 'pick-args', 'pick-values',
     21 	'quote', 'require-macros', 'rshift', 'set', 'set-forcibly!', 'tset', 'values', 'var', 'when',
     22 	'while', 'with-open'
     23 }))
     24 
     25 -- Identifiers.
     26 local initial = lexer.alpha + S('|$%&#*+-/<=>?~^_λ!')
     27 local subsequent = initial + lexer.digit
     28 lex:modify_rule('identifier', token(lexer.IDENTIFIER, initial * subsequent^0 * P('#')^-1))
     29 
     30 -- Strings.
     31 local dq_str = lexer.range('"')
     32 local kw_str = lpeg.B(1 - subsequent) * ':' * subsequent^1
     33 lex:modify_rule('string', token(lexer.STRING, dq_str + kw_str))
     34 
     35 -- Comments.
     36 lex:modify_rule('comment', token(lexer.COMMENT, lexer.to_eol(';')))
     37 
     38 -- Ignore these rules.
     39 -- lex:modify_rule('longstring', P(false))
     40 lex:modify_rule('label', P(false))
     41 lex:modify_rule('operator', P(false))
     42 
     43 lexer.property['scintillua.comment'] = ';'
     44 
     45 return lex