// Match must start at the beginning
private PNode reduceSentenceFragmentStartingAtBeginning(PNode source, out bool didReduce)
{
// Create a matcher
// While there are still "matchers in progress"
// Feed each PNode in the source to each matcher in progress.
// If the matcher indicats it is done then
// Ask for it's list of best matches.
// Add that list to the complete list of best matches.
// Remove the completed matcher from the list of matchers in progress.
// Otherwise,
// Add the list of child matchers it returns to the list of matchers in progress
List <PatternMatcher> matches = getSuccessfulMatchesStartingAtPNode(source); // Get the matches
List <PatternMatcher> bestMatches = getStrongestMatchesFromMatchList(matches); // Select the winners
// Deal with ambiguity (too many matches)
if (bestMatches.Count > 1 ||
bestMatches.Count == 1 && bestMatches[0].MatchedPhrases.Count > 1)
{
didReduce = false;
// Make an ambiguity callback and throw an exception to bail out of this mess.
if (OnAmbiguity != null)
{
OnAmbiguity(this, source, bestMatches);
throw new RuntimeProseLanguageException("Sentence is ambiguous.", source);
}
else
{
throw new RuntimeProseLanguageException("Sentence is ambiguous.", source);
}
}
else if (bestMatches.Count == 0)
{
// We couldn't reduce anything
didReduce = false;
return(source);
}
// Apply the phrase
PatternMatcher bestMatcher = bestMatches[0];
Phrase bestPhrase = bestMatcher.MatchedPhrases[0];
didReduce = true;
// Do any automatic casting necessary to make the arguments match the pattern.
bestMatcher.autoCastArguments();
if (BeforeReduction != null)
{
BeforeReduction(this, source);
}
// REDUCE!
PNode reducedSource = bestPhrase.evaluate(source, bestMatcher);
if (AfterReduction != null)
{
AfterReduction(this, reducedSource);
}
return(reducedSource);
}
