-- Copyright 2006-2015 Mitchell mitchell.att.foicica.com. See LICENSE.
-- Smalltalk LPeg lexer.

local l = require('lexer')
local token, word_match = l.token, l.word_match
local P, R, S = lpeg.P, lpeg.R, lpeg.S

local M = {_NAME = 'smalltalk'}

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

-- Comments.
local comment = token(l.COMMENT, l.delimited_range('"', false, true))

-- Strings.
local sq_str = l.delimited_range("'")
local literal = '$' * l.word
local string = token(l.STRING, sq_str + literal)

-- Numbers.
local number = token(l.NUMBER, l.float + l.integer)

-- Keywords.
local keyword = token(l.KEYWORD, word_match{
  'true', 'false', 'nil', 'self', 'super', 'isNil', 'not', 'Smalltalk',
  'Transcript'
})

-- Types.
local type = token(l.TYPE, word_match{
  'Date', 'Time', 'Boolean', 'True', 'False', 'Character', 'String', 'Array',
  'Symbol', 'Integer', 'Object'
})

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

-- Operators.
local operator = token(l.OPERATOR, S(':=_<>+-/*!()[]'))

-- Labels.
local label = token(l.LABEL, '#' * l.word)

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

M._foldsymbols = {
  _patterns = {'[%[%]]'},
  [l.OPERATOR] = {['['] = 1, [']'] = -1}
}

return M