public static IList<ParserRuleContext> GetAllPossibleParseTrees(Grammar g,
Parser originalParser,
ITokenStream tokens,
int decision,
BitSet alts,
int startIndex,
int stopIndex,
int startRuleIndex)
{
IList<ParserRuleContext> trees = new List<ParserRuleContext>();
// Create a new parser interpreter to parse the ambiguous subphrase
ParserInterpreter parser = DeriveTempParserInterpreter(g, originalParser, tokens);
if (stopIndex >= (tokens.Size - 1))
{
// if we are pointing at EOF token
// EOF is not in tree, so must be 1 less than last non-EOF token
stopIndex = tokens.Size - 2;
}
// get ambig trees
int alt = alts.NextSetBit(0);
while (alt >= 0)
{
// re-parse entire input for all ambiguous alternatives
// (don't have to do first as it's been parsed, but do again for simplicity
// using this temp parser.)
parser.Reset();
parser.AddDecisionOverride(decision, startIndex, alt);
ParserRuleContext t = parser.Parse(startRuleIndex);
GrammarInterpreterRuleContext ambigSubTree =
(GrammarInterpreterRuleContext)Trees.GetRootOfSubtreeEnclosingRegion(t, startIndex, stopIndex);
// Use higher of overridden decision tree or tree enclosing all tokens
if (Trees.IsAncestorOf(parser.OverrideDecisionRoot, ambigSubTree))
{
ambigSubTree = (GrammarInterpreterRuleContext)parser.OverrideDecisionRoot;
}
trees.Add(ambigSubTree);
alt = alts.NextSetBit(alt + 1);
}
return trees;
}
