bool Parser::CreateFirstSetsOnePass() {
bool anySetModified = false;
for (GrammarContainer::const_iterator ite = env_->grammars.begin(); ite != env_->grammars.end(); ++ite) {
Grammar* g = *ite;
const CondinateContainer& conds = g->GetCondinates();
GrammarSymbolSet& firstSet = firstSetContainer_[g->GetLhs()];
for (CondinateContainer::const_iterator ite2 = conds.begin(); ite2 != conds.end(); ++ite2) {
Condinate* c = *ite2;
SymbolVector::iterator ite3 = c->symbols.begin();
for (; ite3 != c->symbols.end(); ++ite3) {
GrammarSymbol& current = *ite3;
anySetModified = MergeNonEpsilonElements(firstSet, firstSetContainer_[current]) || anySetModified;
GrammarSymbolSet& currentFirstSet = firstSetContainer_[current];
if (currentFirstSet.find(NativeSymbols::epsilon) == currentFirstSet.end()) {
break;
}
}
if (ite3 == c->symbols.end()) {
anySetModified = firstSet.insert(NativeSymbols::epsilon).second || anySetModified;
}
}
}
return anySetModified;
}
int Syntaxer::Reduce(int cpos) {
Grammar* g = nullptr;
const Condinate* cond = p_.env->grammars.GetTargetCondinate(cpos, &g);
int length = cond->symbols.front() == NativeSymbols::epsilon ? 0 : cond->symbols.size();
std::string log = ">> [R] `" + Utility::Concat(stack_->symbols.end() - length, stack_->symbols.end()) + "` to `" + g->GetLhs().ToString() + "`. ";
void* newValue = (cond->action != nullptr) ? cond->action->Invoke(stack_->values) : nullptr;
stack_->pop(length);
int nextState = p_.lrTable.GetGoto(stack_->states.back(), g->GetLhs());
Debug::Log(log + "Goto state " + std::to_string(nextState) + ".");
if (nextState < 0) {
Debug::LogError("empty goto item(" + std::to_string(stack_->states.back()) + ", " + g->GetLhs().ToString() + ")");
return nextState;
}
stack_->push(nextState, newValue, g->GetLhs());
return nextState;
}
bool Parser::CreateFollowSetsOnePass() {
bool anySetModified = false;
GrammarSymbolSet gss;
for (GrammarContainer::const_iterator ite = env_->grammars.begin(); ite != env_->grammars.end(); ++ite) {
Grammar* g = *ite;
const CondinateContainer& conds = g->GetCondinates();
for (CondinateContainer::const_iterator ite2 = conds.begin(); ite2 != conds.end(); ++ite2) {
Condinate* current = *ite2;
for (SymbolVector::iterator ite3 = current->symbols.begin(); ite3 != current->symbols.end(); ++ite3) {
GrammarSymbol& symbol = *ite3;
if (symbol.SymbolType() == GrammarSymbolTerminal) {
continue;
}
SymbolVector::iterator ite4 = ite3;
firstSetContainer_.GetFirstSet(gss, ++ite4, current->symbols.end());
anySetModified = MergeNonEpsilonElements(followSetContainer_[symbol], gss) || anySetModified;
if (gss.find(NativeSymbols::epsilon) != gss.end()) {
anySetModified = MergeNonEpsilonElements(followSetContainer_[symbol], followSetContainer_[g->GetLhs()]) || anySetModified;
}
gss.clear();
}
}
}
return anySetModified;
}
