-- Copyright 2006-2023 Mitchell. See LICENSE.
-- ANTLR 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('antlr')

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

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match {
    'abstract', 'break', 'case', 'catch', 'continue', 'default', 'do', 'else',
    'extends', 'final', 'finally', 'for', 'if', 'implements', 'instanceof',
    'native', 'new', 'private', 'protected', 'public', 'return', 'static',
    'switch', 'synchronized', 'throw', 'throws', 'transient', 'try', 'volatile',
    'while', 'package', 'import', 'header', 'options', 'tokens', 'strictfp',
    'false', 'null', 'super', 'this', 'true'
}))

-- Types.
lex:add_rule('type', token(lexer.TYPE, word_match(
                               'boolean byte char class double float int interface long short void')))

-- Functions.
lex:add_rule('func', token(lexer.FUNCTION, 'assert'))

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

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

-- Actions.
local open_brace = token(lexer.OPERATOR, '{')
local close_brace = token(lexer.OPERATOR, '}')
lex:add_rule('action',
             open_brace * token('action', (1 - P('}')) ^ 0) * close_brace ^ -1)
lex:add_style('action', lexer.styles.nothing)

-- Strings.
lex:add_rule('string', token(lexer.STRING, lexer.range("'", true)))

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

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

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

return lex
