com.oracle.truffle.api.dsl

Annotation Type CachedLanguage

@Retention(value=CLASS)
 @Target(value=PARAMETER)
public @interface CachedLanguage

Allows to access the current language instance in specializations or exported messages. The parameter type must be the exact type of the language access or a TruffleLanguage.LanguageReference that provides it. The latter parameter allows to lookup the language lazily, e.g. in a conditional branch. Using this annotation always allows to generate uncached versions of the node.

This annotation can be used in two different ways:

1. Direct language access:

 @GenerateUncached
 abstract static class ExampleNode extends Node {

     abstract Object execute(Object argument);

     @Specialization
     static int doInt(int value,
                     @CachedLanguage MyLanguage language) {
         // use context
         return value;
     }

 }
 

2. Conditional language access:

 @GenerateUncached
 abstract class ExampleNode extends Node {

     abstract Object execute(Object argument);

     @Specialization
     static int doInt(int value,
                     @CachedLanguage LanguageReference ref) {
         if (value == 42) {
             // use context conditionally
             MyLanguage language = ref.get();

         }
         return value;
     }
 }
 

The generated code uses the Node.lookupLanguageReference(Class) method to implement this feature. This method may also be used manually.

Since:

19.0

See Also:

@Cached for more information on using this annotation., @CachedContext to access the language instance.