protected internal override ExpressionSlim VisitParameter(ParameterExpressionSlim node)
{
foreach (var frame in _environment)
{
if (frame.Contains(node))
{
return(node);
}
}
Globals.Add(node);
return(node);
}
/// <summary>
/// Looks up the free variable name in the Reactive metadata and attempts to unify entity types.
/// </summary>
/// <param name="free">The free variable.</param>
/// <param name="metadata">The metadata to unify aginst.</param>
/// <returns>
/// Unifications between the free variable type and the known resource type.
/// </returns>
internal static IEnumerable <KeyValuePair <TypeSlim, Type> > FindAndUnify(ParameterExpressionSlim free, IReactiveMetadata metadata)
{
var reactiveType = ReactiveEntityTypeExtensions.FromTypeSlim(free.Type);
if ((reactiveType & ReactiveEntityType.Func) == ReactiveEntityType.Func)
{
reactiveType ^= ReactiveEntityType.Func;
}
var metadataType = default(Type);
switch (reactiveType)
{
case ReactiveEntityType.Observer:
if (metadata.Observers.TryGetValue(new Uri(free.Name), out var observer))
{
metadataType = observer.Expression.Type;
}
break;
case ReactiveEntityType.Observable:
if (metadata.Observables.TryGetValue(new Uri(free.Name), out var observable))
{
metadataType = observable.Expression.Type;
}
break;
case ReactiveEntityType.SubscriptionFactory:
if (metadata.SubscriptionFactories.TryGetValue(new Uri(free.Name), out var subscriptionFactory))
{
metadataType = subscriptionFactory.Expression.Type;
}
break;
case ReactiveEntityType.Subscription:
if (metadata.Subscriptions.TryGetValue(new Uri(free.Name), out var subscription))
{
metadataType = subscription.Expression.Type;
}
break;
case ReactiveEntityType.StreamFactory:
if (metadata.StreamFactories.TryGetValue(new Uri(free.Name), out var streamFactory))
{
metadataType = streamFactory.Expression.Type;
}
break;
case ReactiveEntityType.Stream:
if (metadata.Streams.TryGetValue(new Uri(free.Name), out var stream))
{
metadataType = stream.Expression.Type;
}
break;
}
if (metadataType != null)
{
var unifier = new DataModelTypeUnifier();
if (unifier.Unify(metadataType, free.Type))
{
return(unifier.Entries);
}
}
return(Array.Empty <KeyValuePair <TypeSlim, Type> >());
}
