-- Copyright 2016-2018 David B. Lamkins <david@lamkins.net>. See License.txt.
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-- Protocol Buffer IDL LPeg lexer.
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-- <https://developers.google.com/protocol-buffers/>
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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('protobuf')
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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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contained syntax import option package message group oneof optional required
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repeated default extend extensions to max reserved service rpc returns
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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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int32 int64 uint32 uint64 sint32 sint64 fixed32 fixed64 sfixed32 sfixed64
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float double bool string bytes enum true false
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]]))
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-- Strings.
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local sq_str = P('L')^-1 * lexer.delimited_range("'", true)
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local dq_str = P('L')^-1 * lexer.delimited_range('"', true)
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lex:add_rule('string', token(lexer.STRING, sq_str + dq_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, lexer.float + lexer.integer))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('<>=|;,.()[]{}')))
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return lex
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