[Python-ideas] Fwd: Fwd: Fwd: unpacking generalisations for list comprehension

[Steven D'Aprano]

On Sun, Oct 16, 2016 at 05:14:54AM +0000, Neil Girdhar wrote:

[Steven (me), refering to Greg]
> > Because as your own email inadvertently reinforces, if sequence
> > unpacking made sense in the context of a list comprehension, it would
> > already be allowed rather than a SyntaxError: it is intentionally
> > prohibited because it doesn't make sense in the context of list comps.
>
> 
> Whoa, hang on a second there.  It is intentionally prohibited because
> Joshua Landau (who helped a lot with writing and implementing the PEP) and
> I felt like there was going to be a long debate and we wanted to get PEP
> 448 checked in.
> 
> If it "didn't make sense" as you say, then we would have said so in the
> PEP. Instead, Josh wrote:
> 
> This was met with a mix of strong concerns about readability and mild
> support. In order not to disadvantage the less controversial aspects of the
> PEP, this was not accepted with the rest of the proposal.

Okay, interesting, and thanks for the correction.

> I don't remember who it was who had those strong concerns (maybe you?)  But
> that's why we didn't include it.

I'm pretty sure it wasn't me. I don't recall being involved at all with 
any discussions about PEP 448, and a quick search has failed to come up 
with anything relevant. I think I sat that one out.



-- 
Steve