[Python-ideas] Fwd: Fwd: Fwd: unpacking generalisations for list comprehension
Steven D'Aprano
steve at pearwood.info
Sun Oct 16 07:41:03 EDT 2016
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
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