-- Copyright 2006-2018 JMS. See License.txt.
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-- Scala LPeg lexer.
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local lexer = require('lexer')
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local token, word_match = lexer.token, lexer.word_match
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local P, R, S = lpeg.P, lpeg.R, lpeg.S
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local lex = lexer.new('scala')
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-- Whitespace.
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local ws = token(lexer.WHITESPACE, lexer.space^1)
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lex:add_rule('whitespace', ws)
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-- Classes.
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lex:add_rule('class', token(lexer.KEYWORD, P('class')) * ws^1 *
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token(lexer.CLASS, lexer.word))
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-- Keywords.
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lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
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abstract case catch class def do else extends false final finally for forSome
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if implicit import lazy match new null object override package private
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protected return sealed super this throw trait try true type val var while
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with yield
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]]))
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-- Types.
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lex:add_rule('type', token(lexer.TYPE, word_match[[
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Array Boolean Buffer Byte Char Collection Double Float Int Iterator LinkedList
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List Long Map None Option Set Short SortedMap SortedSet String TreeMap TreeSet
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]]))
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-- Functions.
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lex:add_rule('function', token(lexer.FUNCTION, lexer.word) * #P('('))
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-- Identifiers.
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lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
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-- Strings.
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local symbol = "'" * lexer.word
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local dq_str = lexer.delimited_range('"', true)
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local tq_str = '"""' * (lexer.any - '"""')^0 * P('"""')^-1
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lex:add_rule('string', token(lexer.STRING, tq_str + symbol + dq_str))
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-- Comments.
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local line_comment = '//' * lexer.nonnewline_esc^0
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local block_comment = '/*' * (lexer.any - '*/')^0 * P('*/')^-1
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lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
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-- Numbers.
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lex:add_rule('number', token(lexer.NUMBER, (lexer.float + lexer.integer) *
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S('LlFfDd')^-1))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>!=^&|?~:;.()[]{}')))
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-- Fold points.
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lex:add_fold_point(lexer.OPERATOR, '{', '}')
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lex:add_fold_point(lexer.COMMENT, '/*', '*/')
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lex:add_fold_point(lexer.COMMENT, '//', lexer.fold_line_comments('//'))
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return lex
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