public override bool Equals(Object obj)
{
if (obj == null || GetType() != obj.GetType())
{
return(false);
}
PDATransition pdat = (PDATransition)obj;
return(InputChar == pdat.InputChar &&
StackHead == pdat.StackHead &&
StackReplace.SequenceEqual(pdat.StackReplace) &&
NewState == pdat.NewState &&
OldState == pdat.OldState);
}
/// <summary>
/// Applies the given transition, to the given run state.
/// </summary>
/// <returns>
/// An IEnumerable of the states resulting from applying the transition.
/// </returns>
private static PDARunState ApplyTransition(PDATransition transition,
PDARunState state)
{
var newState = transition.NewState;
var newStack = state.Stack;
var newInput = state.Input.Substring(1);
var newMatchedSoFar = state.MatchedSoFar + 1;
var isFailure = false;
// If we're not matching against the empty stack, try pop.
if (transition.StackHead != '_')
{
if (newStack.Length > 0)
{
newStack = newStack.Substring(1);
}
else
{
// Cannot pop from the stack, so bail out here.
isFailure = true;
}
}
else if (newStack != "")
{
// Catch illegal use of empty stack transition.
isFailure = true;
}
if (!isFailure)
{
newStack = transition.StackReplace + newStack;
}
var returnState = new PDARunState(newInput, newMatchedSoFar, newStack, newState);
// Check for end-of-input without empty stack - failure.
// We won't be able to empty the stack if there are fewer input
// chars than stack elems, so fail to prevent unnecessary work.
if (isFailure || newInput == "" && newStack.Length > 0 || newInput.Length < newStack.Length)
{
returnState.Failure = true;
}
return(returnState);
}
private static PDACondition ApplyTransition(PDATransition transition, PDACondition condition)
{
var newCurrentInput = new Stack <string>(new Stack <string>(condition.currentInput));
var newStack = new Stack <string>(new Stack <string>(condition.stack));
//We always pop something from stack
newStack.Pop();
//If we should read something from input, we remove it from current input
if (transition.readFromInput != "")
{
newCurrentInput.Pop();
}
//Pushing elements to stack
foreach (string elementToPush in transition.pushToStack.Reverse())
{
if (elementToPush != "")
{
newStack.Push(elementToPush);
}
}
return(new PDACondition(newCurrentInput, newStack, transition.nextState));
}
/// <summary>
/// Applies the given transition, to the given run state.
/// </summary>
/// <returns>
/// An IEnumerable of the states resulting from applying the transition.
/// </returns>
private static PDARunState ApplyTransition(PDATransition transition,
PDARunState state)
{
var newState = transition.NewState;
var newStack = state.Stack;
var newInput = state.Input.Substring(1);
var newMatchedSoFar = state.MatchedSoFar + 1;
var isFailure = false;
// If we're not matching against the empty stack, try pop.
if (transition.StackHead != '_')
{
if (newStack.Length > 0)
{
newStack = newStack.Substring(1);
}
else
{
// Cannot pop from the stack, so bail out here.
isFailure = true;
}
}
else if (newStack != "")
{
// Catch illegal use of empty stack transition.
isFailure = true;
}
if (!isFailure)
{
newStack = transition.StackReplace + newStack;
}
var returnState = new PDARunState(newInput, newMatchedSoFar, newStack, newState);
// Check for end-of-input without empty stack - failure.
// We won't be able to empty the stack if there are fewer input
// chars than stack elems, so fail to prevent unnecessary work.
if (isFailure || newInput == "" && newStack.Length > 0 || newInput.Length < newStack.Length)
{
returnState.Failure = true;
}
return returnState;
}
