public DerivationSequence AddDerivation(DerivationRule derivationRule, string derivedWord)
{
bool derivationIsSilent = derivationRule.Attributes.Contains(DerivationAttribute.Silent);
return(With(
allDerivationsTaken: AllDerivationsTaken.Add(derivationRule),
nonSilentDerivationsTaken: !derivationIsSilent ? NonSilentDerivationsTaken.Add(derivationRule) : null,
nonSilentWordFormProgression: !derivationIsSilent ? NonSilentWordFormProgression.Add(derivedWord) : null));
}
public bool IsInvalidDerivation()
{
/*
* Check if any derivation in the sequence follows a sequence of derivations
* that it's not allowed to follow.
*/
for (int i = 0; i < AllDerivationsTaken.Count; i++)
{
var derivation = AllDerivationsTaken[i];
foreach (var forbiddenPredecessorSequence in derivation.CannotFollow)
{
int nextDerivationOffset = 1;
/*
* The forbidden predecessor sequences are expressed in forward-order in derivations.js,
* because they are easier to think about that way. But the conjugation code works in
* reverse order, so we have to consider the forbidden predecessor sequences in reverse
* order also. So start at the back of the sequence.
*/
for (int g = forbiddenPredecessorSequence.Count - 1; g >= 0; --g, ++nextDerivationOffset)
{
var nextDerivation = AllDerivationsTaken.ElementAtOrDefault(i + nextDerivationOffset);
if (nextDerivation == null ||
nextDerivation.ConjugatedWordType != forbiddenPredecessorSequence[g])
{
break; // A forbidden predecessor sequence was matched. Return true.
}
if (g == 0)
{
return(true);
}
}
}
}
return(false); // No forbidden predecessor sequence was matched.
}
