/interpreter/tags/reactive-pattern-matching/test/edu/vub/at/objects/natives/ExceptionHandlingTest-snippet1

 1def removableFieldsMirror :=
 2  mirror: {
 3    // vectors are not loaded with these unit tests
 4    // we therefore assume only a single field is removed
 5    def removedField := nil;
 6    def removeField( symbol ) {
 7      removedField := symbol;
 8    };
 9    def invokeField( receiver, symbol ) {
10      if: (symbol == removedField) then: {
11        raise: doesNotUnderstandX.new(symbol , self);
12      } else: {
13        super.invokeField( receiver, symbol );
14      }
15    }
16  };
17  
18def test := object: {
19  def visible := nil
20} mirroredBy: removableFieldsMirror;
21
22(reflect: test).removeField(`visible);
23(test.visible == nil).ifTrue: { fail(); };