TokenStreamRewriteEngine.hpp

#ifndef INC_TokenStreamRewriteEngine_hpp__
#define INC_TokenStreamRewriteEngine_hpp__
 
/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 */
 
#include <string>
#include <list>
#include <vector>
#include <map>
#include <utility>
#include <iostream>
#include <iterator>
#include <cassert>
#include <algorithm>
 
#include <antlr/config.hpp>
 
#include <antlr/TokenStream.hpp>
#include <antlr/TokenWithIndex.hpp>
#include <antlr/BitSet.hpp>
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif
 
/** This token stream tracks the *entire* token stream coming from
 *       a lexer, but does not pass on the whitespace (or whatever else
 *       you want to discard) to the parser.
 *
 *       This class can then be asked for the ith token in the input stream.
 *       Useful for dumping out the input stream exactly after doing some
 *       augmentation or other manipulations.   Tokens are index from 0..n-1
 *
 *       You can insert stuff, replace, and delete chunks.       Note that the
 *       operations are done lazily--only if you convert the buffer to a
 *       String.         This is very efficient because you are not moving data around
 *       all the time.   As the buffer of tokens is converted to strings, the
 *       toString() method(s) check to see if there is an operation at the
 *       current index.  If so, the operation is done and then normal String
 *       rendering continues on the buffer.      This is like having multiple Turing
 *       machine instruction streams (programs) operating on a single input tape. :)
 *
 *       Since the operations are done lazily at toString-time, operations do not
 *       screw up the token index values.  That is, an insert operation at token
 *       index i does not change the index values for tokens i+1..n-1.
 *
 *       Because operations never actually alter the buffer, you may always get
 *       the original token stream back without undoing anything.  Since
 *       the instructions are queued up, you can easily simulate transactions and
 *       roll back any changes if there is an error just by removing instructions.
 *       For example,
 *
 *                      TokenStreamRewriteEngine rewriteEngine =
 *                              new TokenStreamRewriteEngine(lexer);
 *                JavaRecognizer parser = new JavaRecognizer(rewriteEngine);
 *                ...
 *                rewriteEngine.insertAfter("pass1", t, "foobar");}
 *                      rewriteEngine.insertAfter("pass2", u, "start");}
 *                      System.out.println(rewriteEngine.toString("pass1"));
 *                      System.out.println(rewriteEngine.toString("pass2"));
 *
 *       You can also have multiple "instruction streams" and get multiple
 *       rewrites from a single pass over the input.     Just name the instruction
 *       streams and use that name again when printing the buffer.      This could be
 *       useful for generating a C file and also its header file--all from the
 *       same buffer.
 *
 *       If you don't use named rewrite streams, a "default" stream is used.
 *
 *       Terence Parr, parrt@cs.usfca.edu
 *       University of San Francisco
 *       February 2004
 */
class TokenStreamRewriteEngine : public TokenStream
{
public:
        typedef ANTLR_USE_NAMESPACE(std)vector<antlr::RefTokenWithIndex> token_list;
        static const char* DEFAULT_PROGRAM_NAME;
#ifndef NO_STATIC_CONSTS
        static const size_t MIN_TOKEN_INDEX;
        static const int PROGRAM_INIT_SIZE;
#else
        enum {
                MIN_TOKEN_INDEX = 0,
                PROGRAM_INIT_SIZE = 100
        };
#endif
 
        struct tokenToStream {
                tokenToStream( ANTLR_USE_NAMESPACE(std)ostream& o ) : out(o) {}
                template <typename T> void operator() ( const T& t ) {
                        out << t->getText();
                }
                ANTLR_USE_NAMESPACE(std)ostream& out;
        };
 
        class RewriteOperation {
        protected:
                RewriteOperation( size_t idx, const ANTLR_USE_NAMESPACE(std)string& txt )
                : index(idx), text(txt)
                {
                }
        public:
                virtual ~RewriteOperation()
                {
                }
                /** Execute the rewrite operation by possibly adding to the buffer.
                 *       Return the index of the next token to operate on.
                 */
                virtual size_t execute( ANTLR_USE_NAMESPACE(std)ostream& /* out */ ) {
                        return index;
                }
                virtual size_t getIndex() const {
                        return index;
                }
                virtual const char* type() const {
                        return "RewriteOperation";
                }
        protected:
                size_t index;
                ANTLR_USE_NAMESPACE(std)string text;
        };
 
        struct executeOperation {
                ANTLR_USE_NAMESPACE(std)ostream& out;
                executeOperation( ANTLR_USE_NAMESPACE(std)ostream& s ) : out(s) {}
                void operator () ( RewriteOperation* t ) {
                        t->execute(out);
                }
        };
 
        /// list of rewrite operations
        typedef ANTLR_USE_NAMESPACE(std)list<RewriteOperation*> operation_list;
        /// map program name to <program counter,program> tuple
        typedef ANTLR_USE_NAMESPACE(std)map<ANTLR_USE_NAMESPACE(std)string,operation_list> program_map;
 
        class InsertBeforeOp : public RewriteOperation
        {
        public:
                InsertBeforeOp( size_t index, const ANTLR_USE_NAMESPACE(std)string& text )
                : RewriteOperation(index, text)
                {
                }
                virtual ~InsertBeforeOp() {}
                virtual size_t execute( ANTLR_USE_NAMESPACE(std)ostream& out )
                {
                        out << text;
                        return index;
                }
                virtual const char* type() const {
                        return "InsertBeforeOp";
                }
        };
 
        class ReplaceOp : public RewriteOperation
        {
        public:
                ReplaceOp(size_t from, size_t to, ANTLR_USE_NAMESPACE(std)string text)
                : RewriteOperation(from,text)
                , lastIndex(to)
                {
                }
                virtual ~ReplaceOp() {}
                virtual size_t execute( ANTLR_USE_NAMESPACE(std)ostream& out ) {
                        out << text;
                        return lastIndex+1;
                }
                virtual const char* type() const {
                        return "ReplaceOp";
                }
        protected:
                size_t lastIndex;
        };
 
        class DeleteOp : public ReplaceOp {
        public:
                DeleteOp(size_t from, size_t to)
                : ReplaceOp(from,to,"")
                {
                }
                virtual const char* type() const {
                        return "DeleteOp";
                }
        };
 
        TokenStreamRewriteEngine(TokenStream& upstream);
 
        TokenStreamRewriteEngine(TokenStream& upstream, size_t initialSize);
 
        RefToken nextToken( void );
 
        void rollback(size_t instructionIndex) {
                rollback(DEFAULT_PROGRAM_NAME, instructionIndex);
        }
 
        /** Rollback the instruction stream for a program so that
         *       the indicated instruction (via instructionIndex) is no
         *       longer in the stream.  UNTESTED!
         */
        void rollback(const ANTLR_USE_NAMESPACE(std)string& programName,
                                          size_t instructionIndex );
 
        void deleteProgram() {
                deleteProgram(DEFAULT_PROGRAM_NAME);
        }
 
        /** Reset the program so that no instructions exist */
        void deleteProgram(const ANTLR_USE_NAMESPACE(std)string& programName) {
                rollback(programName, MIN_TOKEN_INDEX);
        }
 
        void insertAfter( RefTokenWithIndex t,
                                                        const ANTLR_USE_NAMESPACE(std)string& text )
        {
                insertAfter(DEFAULT_PROGRAM_NAME, t, text);
        }
 
        void insertAfter(size_t index, const ANTLR_USE_NAMESPACE(std)string& text) {
                insertAfter(DEFAULT_PROGRAM_NAME, index, text);
        }
 
        void insertAfter( const ANTLR_USE_NAMESPACE(std)string& programName,
                                                        RefTokenWithIndex t,
                                                        const ANTLR_USE_NAMESPACE(std)string& text )
        {
                insertAfter(programName, t->getIndex(), text);
        }
 
        void insertAfter( const ANTLR_USE_NAMESPACE(std)string& programName,
                                                        size_t index,
                                                        const ANTLR_USE_NAMESPACE(std)string& text )
        {
                // to insert after, just insert before next index (even if past end)
                insertBefore(programName,index+1, text);
        }
 
        void insertBefore( RefTokenWithIndex t,
                                                         const ANTLR_USE_NAMESPACE(std)string& text )
        {
                // std::cout << "insertBefore index " << t->getIndex() << " " << text << std::endl;
                insertBefore(DEFAULT_PROGRAM_NAME, t, text);
        }
 
        void insertBefore(size_t index, const ANTLR_USE_NAMESPACE(std)string& text) {
                insertBefore(DEFAULT_PROGRAM_NAME, index, text);
        }
 
        void insertBefore( const ANTLR_USE_NAMESPACE(std)string& programName,
                                                         RefTokenWithIndex t,
                                                         const ANTLR_USE_NAMESPACE(std)string& text )
        {
                insertBefore(programName, t->getIndex(), text);
        }
 
        void insertBefore( const ANTLR_USE_NAMESPACE(std)string& programName,
                                                         size_t index,
                                                         const ANTLR_USE_NAMESPACE(std)string& text )
        {
                addToSortedRewriteList(programName, new InsertBeforeOp(index,text));
        }
 
        void replace(size_t index, const ANTLR_USE_NAMESPACE(std)string& text)
        {
                replace(DEFAULT_PROGRAM_NAME, index, index, text);
        }
 
        void replace( size_t from, size_t to,
                                          const ANTLR_USE_NAMESPACE(std)string& text)
        {
                replace(DEFAULT_PROGRAM_NAME, from, to, text);
        }
 
        void replace( RefTokenWithIndex indexT,
                                          const ANTLR_USE_NAMESPACE(std)string& text )
        {
                replace(DEFAULT_PROGRAM_NAME, indexT->getIndex(), indexT->getIndex(), text);
        }
 
        void replace( RefTokenWithIndex from,
                                          RefTokenWithIndex to,
                                          const ANTLR_USE_NAMESPACE(std)string& text )
        {
                replace(DEFAULT_PROGRAM_NAME, from, to, text);
        }
 
        void replace(const ANTLR_USE_NAMESPACE(std)string& programName,
                                         size_t from, size_t to,
                                         const ANTLR_USE_NAMESPACE(std)string& text )
        {
                addToSortedRewriteList(programName,new ReplaceOp(from, to, text));
        }
 
        void replace( const ANTLR_USE_NAMESPACE(std)string& programName,
                                          RefTokenWithIndex from,
                                          RefTokenWithIndex to,
                                          const ANTLR_USE_NAMESPACE(std)string& text )
        {
                replace(programName,
                                  from->getIndex(),
                                  to->getIndex(),
                                  text);
        }
 
        void remove(size_t index) {
                remove(DEFAULT_PROGRAM_NAME, index, index);
        }
 
        void remove(size_t from, size_t to) {
                remove(DEFAULT_PROGRAM_NAME, from, to);
        }
 
        void remove(RefTokenWithIndex indexT) {
                remove(DEFAULT_PROGRAM_NAME, indexT, indexT);
        }
 
        void remove(RefTokenWithIndex from, RefTokenWithIndex to) {
                remove(DEFAULT_PROGRAM_NAME, from, to);
        }
 
        void remove( const ANTLR_USE_NAMESPACE(std)string& programName,
                                         size_t from, size_t to)
        {
                replace(programName,from,to,"");
        }
 
        void remove( const ANTLR_USE_NAMESPACE(std)string& programName,
                                         RefTokenWithIndex from, RefTokenWithIndex to )
        {
                replace(programName,from,to,"");
        }
 
        void discard(int ttype) {
                discardMask.add(ttype);
        }
 
        RefToken getToken( size_t i )
        {
                return RefToken(tokens.at(i));
        }
 
        size_t getTokenStreamSize() const {
                return tokens.size();
        }
 
        void originalToStream( ANTLR_USE_NAMESPACE(std)ostream& out ) const {
                ANTLR_USE_NAMESPACE(std)for_each( tokens.begin(), tokens.end(), tokenToStream(out) );
        }
 
        void originalToStream( ANTLR_USE_NAMESPACE(std)ostream& out,
                                                                  size_t start, size_t end ) const;
 
        void toStream( ANTLR_USE_NAMESPACE(std)ostream& out ) const {
                toStream( out, MIN_TOKEN_INDEX, getTokenStreamSize());
        }
 
        void toStream( ANTLR_USE_NAMESPACE(std)ostream& out,
                                                const ANTLR_USE_NAMESPACE(std)string& programName ) const
        {
                toStream( out, programName, MIN_TOKEN_INDEX, getTokenStreamSize());
        }
 
        void toStream( ANTLR_USE_NAMESPACE(std)ostream& out,
                                                size_t start, size_t end ) const
        {
                toStream(out, DEFAULT_PROGRAM_NAME, start, end);
        }
 
        void toStream( ANTLR_USE_NAMESPACE(std)ostream& out,
                                                const ANTLR_USE_NAMESPACE(std)string& programName,
                                                size_t firstToken, size_t lastToken ) const;
 
        void toDebugStream( ANTLR_USE_NAMESPACE(std)ostream& out ) const {
                toDebugStream( out, MIN_TOKEN_INDEX, getTokenStreamSize());
        }
 
        void toDebugStream( ANTLR_USE_NAMESPACE(std)ostream& out,
                                                          size_t start, size_t end ) const;
 
        size_t getLastRewriteTokenIndex() const {
                return getLastRewriteTokenIndex(DEFAULT_PROGRAM_NAME);
        }
 
        /** Return the last index for the program named programName
         * return 0 if the program does not exist or the program is empty.
         * (Note this is different from the java implementation that returns -1)
         */
        size_t getLastRewriteTokenIndex(const ANTLR_USE_NAMESPACE(std)string& programName) const {
                program_map::const_iterator rewrites = programs.find(programName);
 
                if( rewrites == programs.end() )
                        return 0;
 
                const operation_list& prog = rewrites->second;
                if( !prog.empty() )
                {
                        operation_list::const_iterator last = prog.end();
                        --last;
                        return (*last)->getIndex();
                }
                return 0;
        }
 
protected:
        /** If op.index > lastRewriteTokenIndexes, just add to the end.
         *       Otherwise, do linear */
        void addToSortedRewriteList(RewriteOperation* op) {
                addToSortedRewriteList(DEFAULT_PROGRAM_NAME, op);
        }
 
        void addToSortedRewriteList( const ANTLR_USE_NAMESPACE(std)string& programName,
                                                                                  RewriteOperation* op );
 
protected:
        /** Who do we suck tokens from? */
        TokenStream& stream;
        /** track index of tokens */
        size_t index;
 
        /** Track the incoming list of tokens */
        token_list tokens;
 
        /** You may have multiple, named streams of rewrite operations.
         *  I'm calling these things "programs."
         *  Maps String (name) -> rewrite (List)
         */
        program_map programs;
 
        /** Which (whitespace) token(s) to throw out */
        BitSet discardMask;
};
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif
 
#endif