-- Copyright 2015-2018 Alejandro Baez (https://keybase.io/baez). See License.txt.
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-- Rust 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('rust')
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-- Whitespace.
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lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
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-- Keywords.
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lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
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abstract alignof as become box break const continue crate do else enum extern
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false final fn for if impl in let loop macro match mod move mut offsetof
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override priv proc pub pure ref return Self self sizeof static struct super
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trait true type typeof unsafe unsized use virtual where while yield
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]]))
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-- Functions.
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lex:add_rule('function', token(lexer.FUNCTION, lexer.word^1 * S("!")))
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-- Library types
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lex:add_rule('library', token(lexer.LABEL, lexer.upper *
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(lexer.lower + lexer.dec_num)^1))
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-- Types.
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lex:add_rule('type', token(lexer.TYPE, word_match[[
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() bool isize usize char str u8 u16 u32 u64 i8 i16 i32 i64 f32 f64
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]]))
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-- Strings.
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local sq_str = P('L')^-1 * lexer.delimited_range("'")
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local dq_str = P('L')^-1 * lexer.delimited_range('"')
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local raw_str = '#"' * (lexer.any - '#')^0 * P('#')^-1
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lex:add_rule('string', token(lexer.STRING, dq_str + raw_str))
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-- Identifiers.
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lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
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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,
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lexer.float +
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P('0b')^-1 * (lexer.dec_num + "_")^1 +
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lexer.integer))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR,
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S('+-/*%<>!=`^~@&|?#~:;,.()[]{}')))
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-- Attributes.
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lex:add_rule('preprocessor', token(lexer.PREPROCESSOR,
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"#[" * (lexer.nonnewline - ']')^0 *
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P("]")^-1))
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-- Fold points.
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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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lex:add_fold_point(lexer.OPERATOR, '(', ')')
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lex:add_fold_point(lexer.OPERATOR, '{', '}')
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return lex
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