private StateCollection CreateParserStates(CGTContent content)
{
rules = CreateRules(content);
StateCollection states = new StateCollection();
foreach (LALRStateRecord record in content.LALRStateTable)
{
State state = new State(record.Index);
states.Add(state);
}
foreach (LALRStateRecord record in content.LALRStateTable)
{
State state = states[record.Index];
foreach (ActionSubRecord subRecord in record.ActionSubRecords)
{
Action action =
ActionFactory.CreateAction(subRecord,
states,
symbols,
rules);
state.Actions.Add(action);
}
}
return(states);
}
private void DoReduce(Token token, ReduceAction action)
{
int reduceLength = action.Rule.Rhs.Length;
State currentState;
// Do not reduce if the rule is single nonterminal and TrimReductions is on
bool skipReduce = ((TrimReductions) &&
(reduceLength == 1) && (action.Rule.Rhs[0] is SymbolNonterminal));
if (skipReduce)
{
stateStack.Pop();
currentState = stateStack.Peek();
}
else
{
Token[] tokens = new Token[reduceLength];
for (int i = 0; i < reduceLength; i++)
{
stateStack.Pop();
tokens[reduceLength - i - 1] = tokenStack.Pop();
}
NonterminalToken nttoken = new NonterminalToken(action.Rule, tokens);
tokenStack.Push(nttoken);
currentState = stateStack.Peek();
if (OnReduce != null)
{
ReduceEventArgs args = new ReduceEventArgs(action.Rule,
nttoken,
currentState);
OnReduce(this, args);
DoReleaseTokens(args.Token);
continueParsing = args.Continue;
}
}
Action gotoAction = currentState.Actions.Get(action.Rule.Lhs);
if (gotoAction is GotoAction)
{
DoGoto(token, (GotoAction)gotoAction);
}
else
{
throw new ParserException("Invalid action table in state");
}
}
private void ParseTerminal(TerminalToken token)
{
State currentState = stateStack.Peek();
Action action = currentState.Actions.Get(token.Symbol);
if (action is ShiftAction)
{
DoShift(token, (ShiftAction)action);
}
else if (action is ReduceAction)
{
DoReduce(token, (ReduceAction)action);
}
else if (action is AcceptAction)
{
DoAccept(token, (AcceptAction)action);
}
else
{
continueParsing = false;
FireParseError(token);
}
}
