[Python-Dev] PEP 553: Built-in debug()

[Barry Warsaw]

On Sep 6, 2017, at 16:55, Fernando Perez <fperez.net at gmail.com> wrote:
> 
> If I may suggest a small API tweak, I think it would be useful if breakpoint() accepted an optional header argument. In IPython, the equivalent for non-postmortem debugging is IPython.embed, which can be given a header. This is useful to provide the user with some information about perhaps where the breakpoint is coming from, relevant data they might want to look at, etc:
> 
> ```
> from IPython import embed
> 
> def f(x=10):
>   y = x+2
>   embed(header="in f")
>   return y
> 
> x = 20
> print(f(x))
> embed(header="Top level")
> ```
> 
> I understand in most cases these are meant to be deleted right after usage and the author is likely to have a text editor open next to the terminal where they're debugging.  But still, I've found myself putting multiple such calls in a code to look at what's going on in different parts of the execution stack, and it can be handy to have a bit of information to get your bearings.
> 
> Just a thought...

Thanks Fernando, this is exactly the kind of feedback from other debuggers that I’m looking for.  It certainly sounds like a handy feature; I’ve found myself wanting something like that from pdb from time to time.

The PEP has an open issue regarding breakpoint() taking *args and **kws, which would just be passed through the call stack.  It sounds like you’d be in favor of that enhancement.

Cheers,
-Barry

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