private void Assign(NonTerminal head, Terminal term, Production production)
{
if (predictiveParseTable[head][term].HasValue)
throw new InvalidGrammarException("Grammar is not LL(1)");
predictiveParseTable[head][term] = production;
}
protected override ParserAction Action(ParseState state, Token token, out Production production, out ParseState nextState)
{
var lr0 = base.Action(state, token, out production, out nextState);
if (token != null && lr0 == ParserAction.Reduce && !Grammar.GetFollowSet(production.Head).Contains(token.Terminal))
return ParserAction.Error;
return lr0;
}
public bool Equals(Production other)
{
if (!Head.Equals(other.Head))
return false;
if (Body.Length != other.Body.Length)
return false;
for (int i = 0; i < Body.Length; i++)
if (!Body[i].Equals(other.Body[i]))
return false;
return true;
}
protected override ParserAction Action(ParseState state, Token token, out Production production, out ParseState nextState)
{
bool shift = false;
bool reduce = false;
if (token == null && state.AcceptingState)
{
production = default(Production);
nextState = null;
return ParserAction.Accept;
}
if (token != null)
{
nextState = automaton[state, token.Terminal];
if (nextState != null)
{
production = default(Production);
shift = true;
}
}
else
nextState = null;
if (state.Count() == 1 && state.First().Position == state.First().Production.Body.Length)
{
nextState = null;
production = state.First().Production;
reduce = true;
}
else
production = default(Production);
if (shift && reduce)
throw new ParseException(String.Format("Shift/Reduce conflict between shift {0} and reduce {1}", nextState, production));
else if (shift)
return ParserAction.Shift;
else if (reduce)
return ParserAction.Reduce;
else if (token == null)
throw new ParseException("Unexpected EOF");
throw new ParseException(String.Format("Unexpected {0} at line {1} column {2}", token.Value, token.Line, token.Column));
}
protected abstract ParserAction Action(ParseState state, Token token, out Production production, out ParseState nextState);
public Item(Production p, int position)
{
Production = p;
Position = position;
}