private static bool parse(List<input> theInputList, ParsingTable theParsingTable, List<GrammarRule> theGrammar)
{
theInputList.Add("úEndSymbol");
dfaState currentState = 0;
Stack<dfaState> helperStack = new Stack<dfaState>();
helperStack.Push(0);
input currentInput;
Action currentAction;
int currentPosition = 0;
while (currentPosition < theInputList.Count)
{
currentInput = theInputList[currentPosition];
currentState = helperStack.Peek();
if (theParsingTable.transitionTable.TryGetValue(new KeyValuePair<dfaState, input>(currentState, currentInput), out currentAction))
{
switch (currentAction.type)
{
case ActionType.Shift:
currentPosition++;
helperStack.Push(currentAction.destiny);
break;
case ActionType.Reduce:
GrammarRule currentRule = theGrammar[currentAction.destiny];
for (int i = 0; i < currentRule.Expression.Count; i++)
{
helperStack.Pop();
}
input X = currentRule.RuleSymbol.id;
Action gotoAction;
dfaState peekedState = helperStack.Peek();
if (theParsingTable.transitionTable.TryGetValue(new KeyValuePair<dfaState, input>(peekedState, X), out gotoAction))
{
helperStack.Push(gotoAction.destiny);
}
else
return false;
break;
case ActionType.Accept:
return true;
default:
return false;
}
}
}
return false;
}
private static ParsingTable GetParsingTable(DFA theAutomaton, HashSet<input> theTokens, HashSet<input> NonTerminals, HashSet<Tuple<dfaState, Symbol, Int32>> ReduceStates, List<GrammarRule> theGrammar)
{
ParsingTable Table = new ParsingTable();
foreach (KeyValuePair<KeyValuePair<dfaState, input>, dfaState> item in theAutomaton.transitionTable)
{
if (NonTerminals.Contains(item.Key.Value))
{
Table.transitionTable.Add(item.Key, new Action(item.Value, ActionType.Goto));
}
else
{
Table.transitionTable.Add(item.Key, new Action(item.Value, ActionType.Shift));
}
}
foreach (dfaState theState in theAutomaton.final)
{
Table.transitionTable.Add(
new KeyValuePair<dfaState, input>(theState, "úEndSymbol"),
new Action(-1, ActionType.Accept));
}
foreach (Tuple<dfaState, Symbol, Int32> item in ReduceStates)
{
if (!NonTerminals.Contains(item.Item2.id))
Table.transitionTable.Add(
new KeyValuePair<dfaState, input>(item.Item1, item.Item2.id),
new Action(item.Item3, ActionType.Reduce));
}
return Table;
}