-- Copyright 2006-2011 Mitchell mitchell<att>caladbolg.net. See LICENSE.
-- R LPeg lexer.

local l = lexer
local token, style, color, word_match = l.token, l.style, l.color, l.word_match
local P, R, S = l.lpeg.P, l.lpeg.R, l.lpeg.S

module(...)

-- Whitespace.
local ws = token(l.WHITESPACE, l.space^1)

-- Comments.
local comment = token(l.COMMENT, '#' * l.nonnewline^0)

-- Strings.
local sq_str = l.delimited_range("'", '\\', true, false, '\n')
local dq_str = l.delimited_range('"', '\\', true, false, '\n')
local string = token(l.STRING, sq_str + dq_str)

-- Numbers.
local number = token(l.NUMBER, (l.float + l.integer) * P('i')^-1)

-- Keywords.
local keyword = token(l.KEYWORD, word_match {
  'break', 'else', 'for', 'if', 'in', 'next', 'repeat', 'return', 'switch',
  'try', 'while', 'Inf', 'NA', 'NaN', 'NULL', 'FALSE', 'TRUE'
})

-- Types.
local type = token(l.TYPE, word_match {
  'array', 'character', 'complex', 'data.frame', 'double', 'factor', 'function',
  'integer', 'list', 'logical', 'matrix', 'numeric', 'vector'
})

-- Identifiers.
local identifier = token(l.IDENTIFIER, l.word)

-- Operators.
local operator = token(l.OPERATOR, S('<->+*/^=.,:;|$()[]{}'))

_rules = {
  { 'whitespace', ws },
  { 'keyword', keyword },
  { 'type', type },
  { 'identifier', identifier },
  { 'string', string },
  { 'comment', comment },
  { 'number', number },
  { 'operator', operator },
  { 'any_char', l.any_char },
}