70 lines
2.4 KiB
C++
70 lines
2.4 KiB
C++
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#include "LALRParser.h"
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LALRParser::LALRParser() {
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//Nothing to do in this version
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}
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LALRParser::~LALRParser() {
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//Nothing to do in this version
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}
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NodeTree<Symbol*>* LALRParser::parseInput(std::string inputString) {
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lexer.setInput(inputString);
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Symbol* token = lexer.next();
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std::vector<ParseAction*>* actionList;
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ParseAction* action;
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stateStack.push(0);
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symbolStack.push(new Symbol("INVALID", false));
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while (true) {
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std::cout << "In state: " << intToString(stateStack.top()) << std::endl;
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actionList = table.get(stateStack.top(), token);
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action = (*(actionList))[actionList->size()-1];
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//std::cout << "Doing ParseAction: " << action->toString() << std::endl;
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switch (action->action) {
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case ParseAction::REDUCE:
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{
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std::cout << "Reduce by " << action->reduceRule->toString() << std::endl;
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int rightSideLength = action->reduceRule->getRightSide().size();
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//Keep track of symbols popped for parse tree
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std::vector<Symbol*> poppedSymbols;
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for (int i = 0; i < rightSideLength; i++) {
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poppedSymbols.push_back(symbolStack.top());
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stateStack.pop();
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symbolStack.pop();
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}
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std::reverse(poppedSymbols.begin(), poppedSymbols.end()); //To put in order
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//Assign the new tree to the new Symbol
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Symbol* newSymbol = action->reduceRule->getLeftSide()->clone();
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newSymbol->setSubTree(reduceTreeCombine(newSymbol, poppedSymbols));
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symbolStack.push(newSymbol);
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std::cout << "top of state is " << intToString(stateStack.top()) << " symbolStack top is " << symbolStack.top()->toString() << std::endl;
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actionList = table.get(stateStack.top(), symbolStack.top());
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action = (*(actionList))[actionList->size()-1];
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stateStack.push(action->shiftState);
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//std::cout << "Reduced, now condition is" << std::endl;
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//std::cout << "top of state is " << intToString(stateStack.top()) << " symbolStack top is " << symbolStack.top()->toString() << std::endl;
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break;
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}
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case ParseAction::SHIFT:
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std::cout << "Shift " << token->toString() << std::endl;
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symbolStack.push(token);
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token = lexer.next();
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stateStack.push(action->shiftState);
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break;
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case ParseAction::ACCEPT:
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std::cout << "ACCEPTED!" << std::endl;
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return(symbolStack.top()->getSubTree());
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break;
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case ParseAction::REJECT:
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std::cout << "REJECTED!" << std::endl;
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std::cout << "REJECTED Symbol was " << token->toString() << std::endl;
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return(NULL);
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break;
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}
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}
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}
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