[Types-sig] Re: Static typing considered HARD

[Stephen Purcell]

Paul Prescod wrote:
>
> What can you do dynamically in Python that you cannot do with
> reflections and introspection? I've written "map", "apply" and the Y
> combinator in Java so I'm pretty confident that the issue is really just
> syntax and ease of use, not capabilities.
> 
> You could prove me wrong by showing a Python programming pattern that
> could not be straightforwardly duplicated using Java reflection.

I have one: dynamic configuration of exception catching --

class Test:
   FAILURE_ERROR_TYPE = AssertionError

   def run(self, result):
       try:
          self.runTest()
       except self.FAILURE_ERROR_TYPE:
          result.failed(self)
       except:
          result.error(self)
       else:
          result.success(self)

This is a cut-down version of a real and justifiable example. Try doing
that in Java with reflection and without resorting to 'instanceof' or
'Class.isInstance()'.

-Steve
_______________________________________________
Steve Purcell                   Squadron Leader
WebSentric AG,       http://www.websentric.com/
____"Would you like to look at my Python?"_____