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Added EOF symbol, making the getTable() saner for ACCEPT and lookahead support in ParseRule

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Nathan Braswell
2013-06-13 14:25:10 -04:00
parent 949dbc532a
commit 0c651a5d9e
9 changed files with 68 additions and 20 deletions
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22
src/Parser.cpp
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@@ -162,6 +162,10 @@ std::string Parser::stateSetToString() {
void Parser::addToTable(State* fromState, Symbol* tranSymbol, ParseAction* action) {
//If this is the first time we're adding to the table, add the EOF character
if (symbolIndexVec.size() == 0)
symbolIndexVec.push_back(new Symbol("$EOF$", false));
//find what state num the from state is
int stateNum = -1;
for (std::vector<State*>::size_type i = 0; i < stateSets.size(); i++) {
@@ -250,15 +254,11 @@ ParseAction* Parser::getTable(int state, Symbol* token) {
}
}
//This is the accepting state, as it is the 1th's state's reduction on EOF, which is not in the symbolIndexVec
//This is the accepting state, as it is the 1th's state's reduction on EOF, which is 0 in the symbolIndexVec
//(This assumes singular goal assignment, a simplification for now)
if (state == 1 && symbolIndex == -1)
if (state == 1 && symbolIndex == 0)
return(new ParseAction(ParseAction::ACCEPT));
//Quick hack, since there is not right now an EOF token, we'll just check for an unrecognized character (-1) and just apply reductions as if it were the first symbol
if (symbolIndex == -1)
symbolIndex = 0;
//If ourside the symbol range of this state (same as NULL), reject
if ( symbolIndex >= table[state]->size() )
return(new ParseAction(ParseAction::REJECT));
@@ -272,10 +272,8 @@ ParseAction* Parser::getTable(int state, Symbol* token) {
return (action);
}
NodeTree* Parser::parseInput(std::string inputString) {
StringReader inputReader;
inputReader.setString(inputString);
Symbol* token = new Symbol("\""+inputReader.word()+"\"", true);
NodeTree* Parser::parseInput(Lexer* lexer) {
Symbol* token = lexer->next();
ParseAction* action;
stateStack.push(0);
@@ -284,6 +282,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
while (true) {
std::cout << "In state: " << intToString(stateStack.top()) << std::endl;
action = getTable(stateStack.top(), token);
std::cout << "Doing ParseAction: " << action->toString() << std::endl;
switch (action->action) {
case ParseAction::REDUCE:
{
@@ -312,7 +311,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
std::cout << "Shift " << token->toString() << std::endl;
symbolStack.push(token);
token = new Symbol("\""+inputReader.word()+"\"", true);
token = lexer->next();
stateStack.push(action->shiftState);
break;
case ParseAction::ACCEPT:
@@ -321,6 +320,7 @@ NodeTree* Parser::parseInput(std::string inputString) {
break;
case ParseAction::REJECT:
std::cout << "REJECTED!" << std::endl;
std::cout << "REJECTED Symbol was " << token->toString() << std::endl;
return(NULL);
break;
}