-- Copyright 2006-2011 Mitchell mitchell<att>caladbolg.net. See LICENSE.
-- Moonscript lexer by leaf corcoran <http://leafo.net>

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

local M = { _NAME = 'moonscript' }

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

local longstring = #('[[' + ('[' * P('=')^0 * '['))
local longstring = longstring * P(function(input, index)
  local level = input:match('^%[(=*)%[', index)
  if level then
    local _, stop = input:find(']'..level..']', index, true)
    return stop and stop + 1 or #input + 1
  end
end)

-- Comments.
local line_comment = '--' * l.nonnewline^0
local block_comment = '--' * longstring
local comment = token(l.COMMENT, block_comment + line_comment)

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

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

-- Keywords.
local keyword = token(l.KEYWORD, word_match {
	'return', 'break', 'for', 'while',
	'if', 'else', 'elseif', 'then', 'export',
	'import', 'from', 'with', 'in', 'and',
	'or', 'not', 'class', 'extends', 'super', 'do',
	'using', 'switch', 'when',
})

local special = token("special", word_match { "true", "false", "nil" })

-- Functions.
local builtin = token(l.FUNCTION, word_match({
	"_G","_VERSION","assert","collectgarbage","dofile","error","getfenv","getmetatable","ipairs","load",
	"loadfile","loadstring","module","next","pairs","pcall","print","rawequal","rawget","rawset","require",
	"select","setfenv","setmetatable","tonumber","tostring","type","unpack","xpcall",

	"coroutine.create","coroutine.resume","coroutine.running","coroutine.status","coroutine.wrap","coroutine.yield",

	"debug.debug","debug.getfenv","debug.gethook","debug.getinfo","debug.getlocal","debug.getmetatable",
	"debug.getregistry","debug.getupvalue","debug.setfenv","debug.sethook","debug.setlocal","debug.setmetatable",
	"debug.setupvalue","debug.traceback",

	"io.close","io.flush","io.input","io.lines","io.open","io.output","io.popen","io.read","io.stderr","io.stdin",
	"io.stdout","io.tmpfile","io.type","io.write",

	"math.abs","math.acos","math.asin","math.atan","math.atan2","math.ceil","math.cos","math.cosh","math.deg",
	"math.exp","math.floor","math.fmod","math.frexp","math.huge","math.ldexp","math.log","math.log10","math.max",
	"math.min","math.modf","math.pi","math.pow","math.rad","math.random","math.randomseed","math.sin","math.sinh",
	"math.sqrt","math.tan","math.tanh",

	"os.clock","os.date","os.difftime","os.execute","os.exit","os.getenv","os.remove","os.rename","os.setlocale",
	"os.time","os.tmpname",

	"package.cpath","package.loaded","package.loaders","package.loadlib","package.path","package.preload",
	"package.seeall",

	"string.byte","string.char","string.dump","string.find","string.format","string.gmatch","string.gsub",
	"string.len","string.lower","string.match","string.rep","string.reverse","string.sub","string.upper",

	"table.concat","table.insert","table.maxn","table.remove","table.sort"
}, "%."))

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

local fndef = token("fndef", P"->" + P"=>")
local err = token(l.ERROR, word_match { "function", "end" })

-- Operators.
local symbol = token("symbol", S("(){}[]"))
local operator = token(l.OPERATOR, '~=' + S('+-*!\\/%^#=<>;:,.'))

-- self ref
local self_var = token("self_ref", "@" * l.word + "self")

local proper_ident = token("proper_ident", R("AZ") * l.word)

local tbl_key = token("tbl_key", l.word * ":" + ":" * l.word )

M._rules = {
  { 'whitespace', ws },
  { 'error', err },
  { 'self', self_var },
  { 'special', special },
  { 'keyword', keyword },
  { 'builtin', builtin },
  { 'identifier', proper_ident + tbl_key + identifier },
  { 'comment', comment },
  { 'number', number },
  { 'string', string },
  { 'fndef', fndef },
  { 'symbol', symbol },
  { 'operator', operator },
  { 'any_char', l.any_char },
}

local style_special = { fore = l.colors.light_blue }
local style_fndef = { fore = l.colors.green }

M._tokenstyles = {
  { 'self_ref', style_special },
  { 'proper_ident', l.style_class },
  { 'fndef', style_fndef },
  { 'symbol', style_fndef },
  { 'special', style_special },
  { 'tbl_key', { fore = l.colors.red } },
}

return M