lexers/gap.lua

   1 -- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
   2 -- Gap LPeg lexer.
   3
   4 local l = require('lexer')
   5 local token, word_match = l.token, l.word_match
   6 local P, R, S = lpeg.P, lpeg.R, lpeg.S
   7
   8 local M = {_NAME = 'gap'}
   9
  10 -- Whitespace.
  11 local ws = token(l.WHITESPACE, l.space^1)
  12
  13 -- Comments.
  14 local comment = token(l.COMMENT, '#' * l.nonnewline^0)
  15
  16 -- Strings.
  17 local sq_str = l.delimited_range("'", true)
  18 local dq_str = l.delimited_range('"', true)
  19 local string = token(l.STRING, sq_str + dq_str)
  20
  21 -- Numbers.
  22 local number = token(l.NUMBER, l.digit^1 * -l.alpha)
  23
  24 -- Keywords.
  25 local keyword = token(l.KEYWORD, word_match{
  26   'and', 'break', 'continue', 'do', 'elif', 'else', 'end', 'fail', 'false',
  27   'fi', 'for', 'function', 'if', 'in', 'infinity', 'local', 'not', 'od', 'or',
  28   'rec', 'repeat', 'return', 'then', 'true', 'until', 'while'
  29 })
  30
  31 -- Identifiers.
  32 local identifier = token(l.IDENTIFIER, l.word)
  33
  34 -- Operators.
  35 local operator = token(l.OPERATOR, S('*+-,./:;<=>~^#()[]{}'))
  36
  37 M._rules = {
  38   {'whitespace', ws},
  39   {'keyword', keyword},
  40   {'identifier', identifier},
  41   {'string', string},
  42   {'comment', comment},
  43   {'number', number},
  44   {'operator', operator},
  45 }
  46
  47 M._foldsymbols = {
  48   _patterns = {'[a-z]+', '#'},
  49   [l.KEYWORD] = {
  50     ['function'] = 1, ['end'] = -1, ['do'] = 1, od = -1, ['if'] = 1, fi = -1,
  51     ['repeat'] = 1, ['until'] = -1
  52   },
  53   [l.COMMENT] = {['#'] = l.fold_line_comments('#')}
  54 }
  55
  56 return M