-- Copyright 2010-2022 Martin Morawetz. See LICENSE.
-- ChucK LPeg lexer.

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

local lex = lexer.new('chuck')

-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match{
  -- Control structures.
  'break', 'continue', 'else', 'for', 'if', 'repeat', 'return', 'switch', 'until', 'while',
  -- Other chuck keywords.
  'function', 'fun', 'spork', 'const', 'new'
}))

-- Constants.
lex:add_rule('constant', token(lexer.CONSTANT, word_match{
  -- Special values.
  'false', 'maybe', 'me', 'null', 'NULL', 'pi', 'true'
}))

-- Types.
lex:add_rule('type', token(lexer.TYPE, word_match('float int time dur void same')))

-- Classes.
lex:add_rule('class', token(lexer.CLASS, word_match{
  -- Class keywords.
  'class', 'extends', 'implements', 'interface', 'private', 'protected', 'public', 'pure', 'static',
  'super', 'this'
}))

-- Global ugens.
lex:add_rule('ugen', token('ugen', word_match('dac adc blackhole')))
lex:add_style('ugen', lexer.styles.constant)

-- Times.
lex:add_rule('time', token('time', word_match('samp ms second minute hour day week')))
lex:add_style('time', lexer.styles.number)

-- Special special value.
lex:add_rule('now', token('now', 'now'))
lex:add_style('now', lexer.styles.constant .. {bold = true})

-- Strings.
local sq_str = P('L')^-1 * lexer.range("'", true)
local dq_str = P('L')^-1 * lexer.range('"', true)
lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))

-- Identifiers.
lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))

-- Comments.
local line_comment = lexer.to_eol('//', true)
local block_comment = lexer.range('/*', '*/')
lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))

-- Numbers.
lex:add_rule('number', token(lexer.NUMBER, lexer.number))

-- Operators.
lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>!=^&|?~:;.()[]{}@')))

return lex