lexers/json.lua

   1 -- Copyright 2006-2013 Brian "Sir Alaran" Schott. See LICENSE.
   2 -- JSON LPeg lexer.
   3 -- Based off of lexer code by Mitchell.
   4
   5 local l = require('lexer')
   6 local token, word_match = l.token, l.word_match
   7 local P, R, S = lpeg.P, lpeg.R, lpeg.S
   8
   9 local M = {_NAME = 'json'}
  10
  11 -- Whitespace.
  12 local ws = token(l.WHITESPACE, l.space^1)
  13
  14 -- Comments.
  15 local comment = token(l.COMMENT, '/*' * (l.any - '*/')^0 * P('*/')^-1)
  16
  17 -- Strings.
  18 local sq_str = P('u')^-1 * l.delimited_range("'", true)
  19 local dq_str = P('U')^-1 * l.delimited_range('"', true)
  20 local string = token(l.STRING, sq_str + dq_str)
  21
  22 -- Numbers.
  23 local integer = S('+-')^-1 * l.digit^1 * S('Ll')^-1
  24 local number = token(l.NUMBER, l.float + integer)
  25
  26 -- Keywords.
  27 local keyword = token(l.KEYWORD, word_match{"true", "false", "null"})
  28
  29 -- Operators.
  30 local operator = token(l.OPERATOR, S('[]{}:,'))
  31
  32 M._rules = {
  33   {'whitespace', ws},
  34   {'comment', comment},
  35   {'string', string},
  36   {'number', number},
  37   {'keyword', keyword},
  38   {'operator', operator},
  39 }
  40
  41 M._foldsymbols = {
  42   _patterns = {'[%[%]{}]', '/%*', '%*/'},
  43   [l.OPERATOR] = {['['] = 1, [']'] = -1, ['{'] = 1, ['}'] = -1},
  44   [l.COMMENT] = {['/*'] = 1, ['*/'] = -1}
  45 }
  46
  47 return M