public Lexer Build(string name)
{
CalcEmptyalbe();
CalcFirstSets();
BuildItemList(name);
PureProduction[] pps = new PureProduction[ProdList.Count];
for (int i = 0; i < ProdList.Count; i++)
{
Production p = ProdList[i];
pps[i] = new PureProduction(p.Name, p.Elems.Length, p.Action);
}
return(new Lexer(Table.ToArray(), pps));
}
public bool TryParse(TokenStream ts, out IASTNode result)
{
Reset();
//PrintStatus();
while (true)
{
LexAction action = GetAction(ts.Peek());
//Console.WriteLine($"Token: {ts.Peek().Type}, Action: {action}");
switch (action.Type)
{
case Accept: result = Symbols.Pop(); return(true);
case Error: result = null; return(false);
case Reduce: {
PureProduction production = Productions[action.Target];
Stack <IASTNode> tmp = new Stack <IASTNode>();
for (int i = 0; i < production.ElemCount; i++)
{
Status.Pop();
tmp.Push(Symbols.Pop());
}
IASTNode node = production.Action != null?
production.Action(tmp.ToArray()) :
(tmp.Count == 1 ? tmp.Pop() : new ASTList(tmp.ToArray()));
Symbols.Push(node);
if (Table[Status.Peek()].TryGetValue(production.Name, out LexAction a))
{
Status.Push(a.Target);
}
else
{
result = null;
return(false);
}
break;
}
case Shift: {
Token token = ts.Read();
Symbols.Push(new ASTLeaf(token));
Status.Push(action.Target);
break;
}
}
//PrintStatus();
}
}
