From: "Schwab,Wilhelm K" <bschwab@anest.ufl.edu>

Subject: FW: Meeting Aliens (callbacks) in the debugger - was this risky?

Date: March 21, 2012 1:57:16 AM GMT+01:00

To: "stephane.ducasse@inria.fr" <stephane.ducasse@inria.fr>

Stef,

I am currently unable to post to the list  (Outlook is being a pain) - could you forward this for me?  I'm curious if I'm living dangerously or simply basking in Smalltalk's wonderful features.

Bill

---

From: Schwab,Wilhelm K
Sent: Tuesday, March 20, 2012 8:55 PM
To: pharo-project@lists.gforge.inria.fr
Subject: Meeting Aliens (callbacks) in the debugger - was this risky?

To see whether one can expect to set breakpoints in callback blocks, I gave it shot in #exampleCqsort:

    cb := Callback
            signature:  'int (*)(const void *, const void *)'
            block: [ :arg1 :arg2 | 
                self halt.
                ((arg1 doubleAt: 1) - (arg2 doubleAt: 1)) sign 
            ].

I then ran the example.  To my pleasant surprise/amazement, a walkback appeared and the debugger was functional; I was able to evaluate the accessors and get numbers.  Is this dangerous in some way, or does it "just work?"  It would be hugely helpful if it is safe.

Bill