-- Copyright 2022-2024 Mitchell. See LICENSE.
-- ? LPeg lexer.

local lexer = lexer
local P, S = lpeg.P, lpeg.S

local lex = lexer.new(...)

-- Keywords.
lex:add_rule('keyword', lex:tag(lexer.KEYWORD, lex:word_match(lexer.KEYWORD)))

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

-- Strings.
local sq_str = lexer.range("'")
local dq_str = lexer.range('"')
lex:add_rule('string', lex:tag(lexer.STRING, sq_str + dq_str))

-- Comments.
lex:add_rule('comment', lex:tag(lexer.COMMENT, lexer.to_eol('#')))

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

-- Operators.
lex:add_rule('operator', lex:tag(lexer.OPERATOR, S('+-*/%^=<>,.{}[]()')))

-- Fold points.
lex:add_fold_point(lexer.KEYWORD, 'start', 'end')
lex:add_fold_point(lexer.OPERATOR, '{', '}')

-- Word lists.
lex:set_word_list(lexer.KEYWORD, {
  'keyword1', 'keyword2', 'keyword3'
})

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

return lex
