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API Documentation

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Lexer.h

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/*------------------------------------------------------------------------------
* Copyright (C) 2003-2006 Ben van Klinken and the CLucene Team
* 
* Distributable under the terms of either the Apache License (Version 2.0) or 
* the GNU Lesser General Public License, as specified in the COPYING file.
------------------------------------------------------------------------------*/
#ifndef _lucene_queryParser_Lexer_
#define _lucene_queryParser_Lexer_

#if defined(_LUCENE_PRAGMA_ONCE)
# pragma once
#endif

#include "CLucene/util/FastCharStream.h"
#include "CLucene/util/Reader.h"
#include "CLucene/util/StringBuffer.h"

#include "TokenList.h"
class QueryParserBase;

CL_NS_DEF(queryParser)

        // A simple Lexer that is used by QueryParser.
        class Lexer:LUCENE_BASE
        {
        private:
                CL_NS(util)::FastCharStream* reader;
                QueryParserBase* queryparser; //holds the queryparser so that we can do callbacks
                bool delSR;  //Indicates if the reader must be deleted or not

    public:
                // Initializes a new instance of the Lexer class with the specified
                // query to lex.
                Lexer(QueryParserBase* queryparser, const TCHAR* query);

                // Initializes a new instance of the Lexer class with the specified
                // TextReader to lex.
                Lexer(QueryParserBase* queryparser, CL_NS(util)::Reader* source);

                //Breaks the input stream onto the tokens list tokens
                void Lex(TokenList *tokens);
                
                ~Lexer();

        private:
                bool GetNextToken(QueryToken* token);

                // Reads an integer number. buf should quite large, probably as large as a field should ever be
                void ReadIntegerNumber(const TCHAR ch, TCHAR* buf, int buflen);

                // Reads an inclusive range like [some words]
                bool ReadInclusiveRange(const TCHAR prev, QueryToken* token);

                // Reads an exclusive range like {some words}
                bool ReadExclusiveRange(const TCHAR prev, QueryToken* token);

                // Reads quoted string like "something else"
                bool ReadQuoted(const TCHAR prev, QueryToken* token);

                bool ReadTerm(const TCHAR prev, QueryToken* token);

        //reads an escaped character into the buf. Buf requires at least 3 characters
                bool ReadEscape(const TCHAR prev, TCHAR* buf);
        };
CL_NS_END
#endif

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