/// <summary>
/// Finds a unique character transition if one exists. The
/// transition must be the only matching single character
/// transition and no other transitions may reach the same
/// state.
/// </summary>
/// <param name="ch">The character to search for</param>
/// <returns>
/// The unique transition state found, or null if none was found
/// </returns>
private NFAState FindUniqueCharTransition(char ch)
{
NFATransition res = null;
foreach (var trans in this.outgoing)
{
if (trans.Match(ch) && trans is NFACharTransition)
{
if (res != null)
{
return(null);
}
res = trans;
}
}
if (res == null)
{
return(null);
}
foreach (var trans in this.outgoing)
{
if (trans != res && trans.State == res.State)
{
return(null);
}
}
return(res?.State);
}
/// <summary>
/// Adds a new outgoing transition.
/// </summary>
/// <param name="trans">The transition to add</param>
/// <returns>The transition target state</returns>
public NFAState AddOut(NFATransition trans)
{
this.outgoing.Add(trans);
if (trans is NFAEpsilonTransition)
{
this.epsilonOut = true;
}
return(trans.State);
}
/// <summary>
/// Adds a new incoming transition.
/// </summary>
/// <param name="trans">The transition to add</param>
public void AddIn(NFATransition trans)
{
this.incoming.Add(trans);
}