-- Copyright 2013-2023 Mitchell. See LICENSE.
-- Dart LPeg lexer.
-- Written by Brian Schott (@Hackerpilot on Github).
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, S = lpeg.P, lpeg.S

local lex = lexer.new('dart')

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

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match {
    'assert', 'break', 'case', 'catch', 'class', 'const', 'continue', 'default',
    'do', 'else', 'enum', 'extends', 'false', 'final', 'finally', 'for', 'if',
    'in', 'is', 'new', 'null', 'rethrow', 'return', 'super', 'switch', 'this',
    'throw', 'true', 'try', 'var', 'void', 'while', 'with'
}))

-- Built-ins.
lex:add_rule('builtin', token(lexer.CONSTANT, word_match {
    'abstract', 'as', 'dynamic', 'export', 'external', 'factory', 'get',
    'implements', 'import', 'library', 'operator', 'part', 'set', 'static',
    'typedef'
}))

-- Strings.
local sq_str = S('r') ^ -1 * lexer.range("'", true)
local dq_str = S('r') ^ -1 * lexer.range('"', true)
local tq_str = S('r') ^ -1 * (lexer.range("'''") + lexer.range('"""'))
lex:add_rule('string', token(lexer.STRING, tq_str + 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('/*', '*/', false, false, true)
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('#?=!<>+-*$/%&|^~.,;()[]{}')))

-- Annotations.
lex:add_rule('annotation', token(lexer.ANNOTATION, '@' * lexer.word ^ 1))

-- Fold points.
lex:add_fold_point(lexer.OPERATOR, '{', '}')
lex:add_fold_point(lexer.COMMENT, '/*', '*/')

lexer.property['scintillua.comment'] = '//'

return lex
