Getting return type of generated Closure at runtime

[Jan Lukavský]

Hi,

I'm struggling with something I believe should be possible - when a 
Closure is parsed at runtime, it should be possible to retrieve its 
generic return type.

I have the following (in Java):

  @Test
  public void testClosureReturnTypeExtraction() {
    String script = "def a = { 1L }";
    Closure<?> closure = (Closure<?>) compile(script).run();
    Class<?> returnType = retrieveReturnTypeFrom(closure);        // 
how to implement this??
    assertEquals(Long.class, returnType);
  }

What I cannot figure out is how to extract the type information from the 
generated closure. I believe the type information should be there (or at 
least it should be possible to put it there). So far, my best attempt 
was, that I got that the type argument is "V". :-)

Any pointers would be appreciated.

Cheers,

 Jan