//given Production A := <alpha> ~B<beta>,a
//return first(<beta>a)
private static List <int> getFirst(Production e)
{
List <int> first = new List <int>();
//where B in Rules
int place = e.Place;
//B is the last one,<beta> is empty
if (place == e.Rules().Length - 1)
{
//end with #
if (e.Nexttok == -1)
{
//return #
first.Add(-1);
return(first);
}
else
{
//return a
return(ParserGenerate.first[Token.GetToken(e.Nexttok)]);
}
}
else
{
// return first(<beta>)
return(ParserGenerate.first[Token.GetToken(e.Rules()[place + 1])]);
}
}
//generate an Production throungh a new Production
public Production(Production former, int initplace = 0, int nexttok = -1)
{
this.tokens = former.Rules();
this.nexttok = nexttok;
this.place = initplace;
this.lhandle = former.lhandle;
this.mrule = former.mrule;
}
// recuresive throught rightmost nonterminal
//ResultID : number in the ParseResult, which should include current reduce rule
public ParseNode GenerateParseTree(ParseNode node)
{
if (node.thisTok.ttype == Ttype.Terminal)
{
return(node);
}
Production currRule = ParserResult[ResultID];
node.geneTok = new ParseNode[currRule.Rules().Length];
for (int i = currRule.Rules().Length - 1; i >= 0; i--)
{
Token token = Token.GetToken(currRule.Rules()[i]);
if (token.ttype == Ttype.Nontermi)
{
ResultID--;
}
node.geneTok[i] = GenerateParseTree(new ParseNode(token));
}
return(node);
}
public void ParseTable()
{
init();
// Index for current lexical Analyze result
int currResultTok = 0;
bool accepted = false;
ParseStack.Push(Tuple.Create(0, Token.tokens[0]));
while (!accepted)
{
Token nexttok;
if (currResultTok < Analysis.ResultTable.Count)
{
nexttok = StrType.Res2Token[Analysis.ResultTable[currResultTok].type];
}
else
{
nexttok = Token.GetToken(-1);
}
Tuple <Ptype, int> nextact;
Tuple <int, Token> nexttuple = Tuple.Create(ParseStack.Peek().Item1, nexttok);
//there is no Action in next given tuple
if (!Action.ContainsKey(nexttuple))
{
Tuple <int, Token> emptyreduce = Tuple.Create(ParseStack.Peek().Item1, Token.GetToken(-1));
//no empty reduce
if (Action.ContainsKey(emptyreduce))
{
nextact = Action[emptyreduce];
}
else
{
PanicRecover(ref currResultTok);
break;
}
}
else
{
nextact = Action[nexttuple];
}
switch (nextact.Item1)
{
case Ptype.move:
{
ParseStack.Push(Tuple.Create(nextact.Item2, nexttok));
ShiftToken(ref currResultTok);
break;
}
case Ptype.reduce:
{
Production rule = Production.formalGrammar[nextact.Item2];
int tokNum = rule.Rules().Length;
while (tokNum > 0)
{
ParseStack.Pop();
tokNum--;
}
//top equal to -1 will not be allowded
if (ParseStack.Peek().Item1 == -1)
{
//error handling
PanicRecover(ref currResultTok);
}
//next state
int nextsta = ParseStack.Peek().Item1;
ParseStack.Push(Tuple.Create(Goto[Tuple.Create(closures[nextsta], Token.tokens[rule.Nonterminal()])], Token.tokens[rule.Nonterminal()]));
AddParseResult(rule);
break;
}
case Ptype.accept:
{
accepted = true;
ResultID = ParserResult.Count - 1;
AcceptAction();
break;
}
}
}
if (afterPanicRecover)
{
UIHelper.Log(GeneticStringClass.ITTerminate);
Thread.CurrentThread.Abort();
}
}