Parser.hpp

#ifndef INC_Parser_hpp__
#define INC_Parser_hpp__
 
/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id$
 */
 
#include <antlr/config.hpp>
 
#include <iostream>
#include <exception>
 
#include <antlr/BitSet.hpp>
#include <antlr/TokenBuffer.hpp>
#include <antlr/RecognitionException.hpp>
#include <antlr/MismatchedTokenException.hpp>
#include <antlr/ASTFactory.hpp>
#include <antlr/ParserSharedInputState.hpp>
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif
 
extern bool DEBUG_PARSER;
 
/** A generic ANTLR parser (LL(k) for k>=1) containing a bunch of
 * utility routines useful at any lookahead depth.  We distinguish between
 * the LL(1) and LL(k) parsers because of efficiency.  This may not be
 * necessary in the near future.
 *
 * Each parser object contains the state of the parse including a lookahead
 * cache (the form of which is determined by the subclass), whether or
 * not the parser is in guess mode, where tokens come from, etc...
 *
 * <p>
 * During <b>guess</b> mode, the current lookahead token(s) and token type(s)
 * cache must be saved because the token stream may not have been informed
 * to save the token (via <tt>mark</tt>) before the <tt>try</tt> block.
 * Guessing is started by:
 * <ol>
 * <li>saving the lookahead cache.
 * <li>marking the current position in the TokenBuffer.
 * <li>increasing the guessing level.
 * </ol>
 *
 * After guessing, the parser state is restored by:
 * <ol>
 * <li>restoring the lookahead cache.
 * <li>rewinding the TokenBuffer.
 * <li>decreasing the guessing level.
 * </ol>
 *
 * @see antlr.Token
 * @see antlr.TokenBuffer
 * @see antlr.TokenStream
 * @see antlr.LL1Parser
 * @see antlr.LLkParser
 *
 * @todo add constructors with ASTFactory.
 */
class ANTLR_API Parser {
protected:
        Parser(TokenBuffer& input)
        : inputState(new ParserInputState(input)), astFactory(0), traceDepth(0)
        {
        }
        Parser(TokenBuffer* input)
        : inputState(new ParserInputState(input)), astFactory(0), traceDepth(0)
        {
        }
        Parser(const ParserSharedInputState& state)
        : inputState(state), astFactory(0), traceDepth(0)
        {
        }
public:
        virtual ~Parser()
        {
        }
 
        /** Return the token type of the ith token of lookahead where i=1
         * is the current token being examined by the parser (i.e., it
         * has not been matched yet).
         */
        virtual int LA(unsigned int i)=0;
 
        /// Return the i-th token of lookahead
        virtual RefToken LT(unsigned int i)=0;
 
        /** DEPRECATED! Specify the factory to be used during tree building. (Compulsory)
         * Setting the factory is nowadays compulsory.
         * @see setASTFactory
         */
        virtual void setASTNodeFactory( ASTFactory *factory )
        {
                astFactory = factory;
        }
        /** Specify the factory to be used during tree building. (Compulsory)
         * Setting the factory is nowadays compulsory.
         */
        virtual void setASTFactory( ASTFactory *factory )
        {
                astFactory = factory;
        }
        /** Return a pointer to the ASTFactory used.
         * So you might use it in subsequent treewalkers or to reload AST's
         * from disk.
         */
        virtual ASTFactory* getASTFactory()
        {
                return astFactory;
        }
        /** Get the root AST node of the generated AST. When using a custom AST type
         * or heterogenous AST's, you'll have to convert it to the right type
         * yourself.
         */
        virtual RefAST getAST() = 0;
 
        /// Return the filename of the input file.
        virtual inline ANTLR_USE_NAMESPACE(std)string getFilename() const
        {
                return inputState->filename;
        }
        /// Set the filename of the input file (used for error reporting).
        virtual void setFilename(const ANTLR_USE_NAMESPACE(std)string& f)
        {
                inputState->filename = f;
        }
 
        virtual void setInputState(ParserSharedInputState state)
        {
                inputState = state;
        }
        virtual inline ParserSharedInputState getInputState() const
        {
                return inputState;
        }
 
        /// Get another token object from the token stream
        virtual void consume()=0;
        /// Consume tokens until one matches the given token
        virtual void consumeUntil(int tokenType)
        {
                while (LA(1) != Token::EOF_TYPE && LA(1) != tokenType)
                        consume();
        }
 
        /// Consume tokens until one matches the given token set
        virtual void consumeUntil(const BitSet& set)
        {
                while (LA(1) != Token::EOF_TYPE && !set.member(LA(1)))
                        consume();
        }
 
        /** Make sure current lookahead symbol matches token type <tt>t</tt>.
         * Throw an exception upon mismatch, which is catch by either the
         * error handler or by the syntactic predicate.
         */
        virtual void match(int t)
        {
                if ( DEBUG_PARSER )
                {
                        traceIndent();
                        ANTLR_USE_NAMESPACE(std)cout << "enter match(" << t << ") with LA(1)=" << LA(1) << ANTLR_USE_NAMESPACE(std)endl;
                }
                if ( LA(1) != t )
                {
                        if ( DEBUG_PARSER )
                        {
                                traceIndent();
                                ANTLR_USE_NAMESPACE(std)cout << "token mismatch: " << LA(1) << "!=" << t << ANTLR_USE_NAMESPACE(std)endl;
                        }
                        throw MismatchedTokenException(getTokenNames(), getNumTokens(), LT(1), t, false, getFilename());
                }
                else
                {
                        // mark token as consumed -- fetch next token deferred until LA/LT
                        consume();
                }
        }
 
        virtual void matchNot(int t)
        {
                if ( LA(1)==t )
                {
                        // Throws inverted-sense exception
                        throw MismatchedTokenException(getTokenNames(), getNumTokens(), LT(1), t, true, getFilename());
                }
                else
                {
                        // mark token as consumed -- fetch next token deferred until LA/LT
                        consume();
                }
        }
 
        /** Make sure current lookahead symbol matches the given set
         * Throw an exception upon mismatch, which is catch by either the
         * error handler or by the syntactic predicate.
         */
        virtual void match(const BitSet& b)
        {
                if ( DEBUG_PARSER )
                {
                        traceIndent();
                        ANTLR_USE_NAMESPACE(std)cout << "enter match(" << "bitset" /*b.toString()*/
                                << ") with LA(1)=" << LA(1) << ANTLR_USE_NAMESPACE(std)endl;
                }
                if ( !b.member(LA(1)) )
                {
                        if ( DEBUG_PARSER )
                        {
                                traceIndent();
                                ANTLR_USE_NAMESPACE(std)cout << "token mismatch: " << LA(1) << " not member of "
                                        << "bitset" /*b.toString()*/ << ANTLR_USE_NAMESPACE(std)endl;
                        }
                        throw MismatchedTokenException(getTokenNames(), getNumTokens(), LT(1), b, false, getFilename());
                }
                else
                {
                        // mark token as consumed -- fetch next token deferred until LA/LT
                        consume();
                }
        }
 
        /** Mark a spot in the input and return the position.
         * Forwarded to TokenBuffer.
         */
        virtual inline unsigned int mark()
        {
                return inputState->getInput().mark();
        }
        /// rewind to a previously marked position
        virtual inline void rewind(unsigned int pos)
        {
                inputState->getInput().rewind(pos);
        }
        /** called by the generated parser to do error recovery, override to
         * customize the behaviour.
         */
        virtual void recover(const RecognitionException&, const BitSet& tokenSet)
        {
                consume();
                consumeUntil(tokenSet);
        }
 
        /// Parser error-reporting function can be overridden in subclass
        virtual void reportError(const RecognitionException& ex);
        /// Parser error-reporting function can be overridden in subclass
        virtual void reportError(const ANTLR_USE_NAMESPACE(std)string& s);
        /// Parser warning-reporting function can be overridden in subclass
        virtual void reportWarning(const ANTLR_USE_NAMESPACE(std)string& s);
 
        /// get the token name for the token number 'num'
        virtual const char* getTokenName(int num) const = 0;
        /// get a vector with all token names
        virtual const char* const* getTokenNames() const = 0;
        /** Get the number of tokens defined.
         * This one should be overridden in subclasses.
         */
        virtual int getNumTokens(void) const = 0;
 
        /** Set or change the input token buffer */
//      void setTokenBuffer(TokenBuffer<Token>* t);
 
        virtual void traceIndent();
        virtual void traceIn(const char* rname);
        virtual void traceOut(const char* rname);
protected:
//      void setTokenNames(const char** tokenNames_);
 
        ParserSharedInputState inputState;
 
//      /// AST return value for a rule is squirreled away here
//      RefAST returnAST;
 
        /// AST support code; parser and treeparser delegate to this object
        ASTFactory *astFactory;
 
        // used to keep track of the indentation for the trace
        int traceDepth;
 
        /** Utility class which allows tracing to work even when exceptions are
         * thrown.
         */
        class Tracer { /*{{{*/
        private:
                Parser* parser;
                const char* text;
        public:
                Tracer(Parser* p,const char * t)
                : parser(p), text(t)
                {
                        parser->traceIn(text);
                }
                ~Tracer()
                {
#ifdef ANTLR_CXX_SUPPORTS_UNCAUGHT_EXCEPTION
                        // Only give trace if there's no uncaught exception..
                        if(!ANTLR_USE_NAMESPACE(std)uncaught_exceptions())
#endif
                                parser->traceOut(text);
                }
        private:
                Tracer(const Tracer&);                                                  // undefined
                const Tracer& operator=(const Tracer&); // undefined
                /*}}}*/
        };
private:
        Parser(const Parser&);                                                          // undefined
        const Parser& operator=(const Parser&);         // undefined
};
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif
 
#endif //INC_Parser_hpp__