[plt-scheme] Hang in macro stepper when macro expansion does not terminate

From: Brian Mastenbrook (brian at mastenbrook.net)
Date: Wed Sep 2 19:39:28 EDT 2009

On Sep 2, 2009, at 5:34 PM, Ryan Culpepper wrote:

> On Sep 2, 2009, at 5:53 PM, Matthias Felleisen wrote:
>> Sadly Ryan thinks that the macro stepper should execute the code  
>> through which you step. I am hoping that everyone on this list can  
>> help me convince him that this shouldn't be the case ...
>> Use STOP to kill the execution as normal.
> Matthias: This is not about nonterminating execution. It is about  
> nonterminating expansion.
> Brian: Clicking Stop is supposed to interrupt expansion. I'll try to  
> see why it isn't working. BTW, what platform do you see the problem  
> on?

Sorry, I forgot to include those details in my original message. I'm  
using PLT 4.2.1 on OS X. When I click Stop the first time, the macro  
stepper appears, but then it hangs again for a long time. It seems  
that the longer I let it go before clicking "Stop", the longer it  
takes for the stepper to appear. When I first tried this, I had let it  
run for a while, and so when I clicked Stop I thought it had hung  

Brian Mastenbrook
brian at mastenbrook.net

Posted on the users mailing list.