lexers/io_lang.lua

   1 -- Copyright 2006-2015 Mitchell mitchell.att.foicica.com. See LICENSE.
   2 -- Io 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 = 'io_lang'}
   9
  10 -- Whitespace.
  11 local ws = token(l.WHITESPACE, l.space^1)
  12
  13 -- Comments.
  14 local line_comment = (P('#') + '//') * l.nonnewline^0
  15 local block_comment = '/*' * (l.any - '*/')^0 * P('*/')^-1
  16 local comment = token(l.COMMENT, line_comment + block_comment)
  17
  18 -- Strings.
  19 local sq_str = l.delimited_range("'")
  20 local dq_str = l.delimited_range('"')
  21 local tq_str = '"""' * (l.any - '"""')^0 * P('"""')^-1
  22 local string = token(l.STRING, tq_str + sq_str + dq_str)
  23
  24 -- Numbers.
  25 local number = token(l.NUMBER, l.float + l.integer)
  26
  27 -- Keywords.
  28 local keyword = token(l.KEYWORD, word_match{
  29   'block', 'method', 'while', 'foreach', 'if', 'else', 'do', 'super', 'self',
  30   'clone', 'proto', 'setSlot', 'hasSlot', 'type', 'write', 'print', 'forward'
  31 })
  32
  33 -- Types.
  34 local type = token(l.TYPE, word_match{
  35   'Block', 'Buffer', 'CFunction', 'Date', 'Duration', 'File', 'Future', 'List',
  36   'LinkedList', 'Map', 'Nop', 'Message', 'Nil', 'Number', 'Object', 'String',
  37   'WeakLink'
  38 })
  39
  40 -- Identifiers.
  41 local identifier = token(l.IDENTIFIER, l.word)
  42
  43 -- Operators.
  44 local operator = token(l.OPERATOR, S('`~@$%^&*-+/=\\<>?.,:;()[]{}'))
  45
  46 M._rules = {
  47   {'whitespace', ws},
  48   {'keyword', keyword},
  49   {'type', type},
  50   {'identifier', identifier},
  51   {'string', string},
  52   {'comment', comment},
  53   {'number', number},
  54   {'operator', operator},
  55 }
  56
  57 M._foldsymbols = {
  58   _patterns = {'[%(%)]', '/%*', '%*/', '#', '//'},
  59   [l.OPERATOR] = {['('] = 1, [')'] = -1},
  60   [l.COMMENT] = {
  61     ['/*'] = 1, ['*/'] = -1, ['#'] = l.fold_line_comments('#'),
  62     ['//'] = l.fold_line_comments('//')
  63   }
  64 }
  65
  66 return M