/**
* Adding a new config means merging contexts with existing configs for
* {@code (s, i, pi, _)}, where {@code s} is the
* {@link ATNConfig#state}, {@code i} is the {@link ATNConfig#alt}, and
* {@code pi} is the {@link ATNConfig#semanticContext}. We use
* {@code (s,i,pi)} as key.
*
* <p>This method updates {@link #dipsIntoOuterContext} and
* {@link #hasSemanticContext} when necessary.</p>
*/
public bool Add(ATNConfig config, MergeCache mergeCache)
{
if (readOnly)
{
throw new Exception("This set is readonly");
}
if (config.semanticContext != SemanticContext.NONE)
{
hasSemanticContext = true;
}
if (config.OuterContextDepth > 0)
{
dipsIntoOuterContext = true;
}
ATNConfig existing = configLookup.GetOrAdd(config);
if (existing == config)
{ // we added this new one
cachedHashCode = -1;
configs.Add(config); // track order here
return(true);
}
// a previous (s,i,pi,_), merge with it and save result
bool rootIsWildcard = !fullCtx;
PredictionContext merged = PredictionContext.Merge(existing.context, config.context, rootIsWildcard, mergeCache);
// no need to check for existing.context, config.context in cache
// since only way to create new graphs is "call rule" and here. We
// cache at both places.
existing.reachesIntoOuterContext = Math.Max(existing.reachesIntoOuterContext, config.reachesIntoOuterContext);
// make sure to preserve the precedence filter suppression during the merge
if (config.IsPrecedenceFilterSuppressed)
{
existing.SetPrecedenceFilterSuppressed(true);
}
existing.context = merged; // replace context; no need to alt mapping
return(true);
}