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tim |
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/* ANTLR Translator Generator |
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* Project led by Terence Parr at http://www.jGuru.com |
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* Software rights: http://www.antlr.org/license.html |
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* |
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gezelter |
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* $Id$ |
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tim |
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*/ |
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#include "antlr/TokenStreamSelector.hpp" |
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#include "antlr/TokenStreamRetryException.hpp" |
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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namespace antlr { |
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#endif |
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/** A token stream MUX (multiplexor) knows about n token streams |
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* and can multiplex them onto the same channel for use by token |
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* stream consumer like a parser. This is a way to have multiple |
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* lexers break up the same input stream for a single parser. |
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* Or, you can have multiple instances of the same lexer handle |
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* multiple input streams; this works great for includes. |
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*/ |
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TokenStreamSelector::TokenStreamSelector() |
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: input(0) |
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{ |
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} |
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TokenStreamSelector::~TokenStreamSelector() |
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{ |
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} |
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void TokenStreamSelector::addInputStream(TokenStream* stream, const ANTLR_USE_NAMESPACE(std)string& key) |
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{ |
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inputStreamNames[key] = stream; |
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} |
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TokenStream* TokenStreamSelector::getCurrentStream() const |
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{ |
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return input; |
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} |
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TokenStream* TokenStreamSelector::getStream(const ANTLR_USE_NAMESPACE(std)string& sname) const |
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{ |
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inputStreamNames_coll::const_iterator i = inputStreamNames.find(sname); |
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if (i == inputStreamNames.end()) { |
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throw ANTLR_USE_NAMESPACE(std)string("TokenStream ")+sname+" not found"; |
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} |
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return (*i).second; |
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} |
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RefToken TokenStreamSelector::nextToken() |
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{ |
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// keep looking for a token until you don't |
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// get a retry exception |
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for (;;) { |
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try { |
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return input->nextToken(); |
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} |
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catch (TokenStreamRetryException&) { |
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// just retry "forever" |
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} |
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} |
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} |
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TokenStream* TokenStreamSelector::pop() |
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{ |
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TokenStream* stream = streamStack.top(); |
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streamStack.pop(); |
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select(stream); |
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return stream; |
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} |
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void TokenStreamSelector::push(TokenStream* stream) |
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{ |
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streamStack.push(input); |
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select(stream); |
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} |
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void TokenStreamSelector::push(const ANTLR_USE_NAMESPACE(std)string& sname) |
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{ |
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streamStack.push(input); |
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select(sname); |
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} |
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void TokenStreamSelector::retry() |
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{ |
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throw TokenStreamRetryException(); |
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} |
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/** Set the stream without pushing old stream */ |
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void TokenStreamSelector::select(TokenStream* stream) |
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{ |
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input = stream; |
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} |
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void TokenStreamSelector::select(const ANTLR_USE_NAMESPACE(std)string& sname) |
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{ |
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inputStreamNames_coll::const_iterator i = inputStreamNames.find(sname); |
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if (i == inputStreamNames.end()) { |
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throw ANTLR_USE_NAMESPACE(std)string("TokenStream ")+sname+" not found"; |
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} |
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input = (*i).second; |
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} |
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#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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} |
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#endif |
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