public T Reduce <T>(T aggregator, ReduceAction <T> action)
{
T result = aggregator;
foreach (WikiPageSection section in Subsections)
{
result = action(section, result);
}
return(result);
}
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;
if (reduceLength == 0)
{
nttoken = new NonterminalToken(action.Rule, tokens, token.Location);
}
else
{
nttoken = new NonterminalToken(action.Rule, tokens, tokens[reduceLength - 1].Location);
}
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 DoReduce(Token token, ReduceAction action)
{
int reduceLength = action.Rule.Rhs.Length;
State currentState;
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;
}
}
lalr.Action gotoAction = currentState.Actions.Get(action.Rule.Lhs);
if (gotoAction is GotoAction)
{
DoGoto(token, (GotoAction)gotoAction);
}
else
{
throw new ParserException("Tabla de acciones inválida en el estado");
}
}
public PureProduction(string name, int elemCount, ReduceAction action)
{
Name = name;
ElemCount = elemCount;
Action = action;
}
private void SetAction(ParserState state, ProductionEntry key, ParserAction newAction)
{
if (key is NonTerminal nt)
{
Console.WriteLine();
}
if (state.Action.ContainsKey(key.ID))
{
var oldAction = state.Action[key.ID];
if (oldAction.ToString() == newAction.ToString())
{
return;
}
if (!(oldAction is AcceptAction) && !(newAction is AcceptAction))
{
if (oldAction.Name != newAction.Name)
{
//Shift/Reduce Conflict
ShiftAction shiftAction = (oldAction.Name == "shift" ? oldAction : newAction) as ShiftAction;
ReduceAction reduceAction = (oldAction.Name == "shift" ? newAction : oldAction) as ReduceAction;
var prod = reduceAction.Production;
var term = key as Terminal;
//Resolve based on precedence and associativity
if (prod.Precendece > term.Precedence ||
(prod.Precendece == term.Precedence && prod.Associatvity == OperatorAssociativity.Left))
{
state.Action[key.ID] = reduceAction;
}
else
{
state.Action[key.ID] = shiftAction;
}
return;
}
else if (newAction is ReduceAction)
{
//Reduce/Reduce conflict
var newProd = (newAction as ReduceAction).Production;
var oldProd = (oldAction as ReduceAction).Production;
bool newFirst = false;
if (newProd.Lhs != oldProd.Lhs)
{
//Find the NonTerminal to appear first
newFirst = newProd.Lhs.ID < oldProd.Lhs.ID;
}
else
{
//Find the production to appear first
foreach (var p in newProd.Lhs.Productions)
{
if (p != newProd && p != oldProd)
{
continue;
}
if (p == newProd)
{
newFirst = true;
}
break;
}
}
//Resolve based on first appearance
if (newFirst)
{
state.Action[key.ID] = newAction;
}
return;
}
else
{
throw new Exception($"Conflict in state {state} on entry {key}. Cannot resolve shift/shift conflict.");
}
}
}
state.Action[key.ID] = newAction;
}
