[Python-ideas] Proposal for function expressions

[George Sakkis]

On Tue, Jul 14, 2009 at 11:55 PM, Chris Rebert<pyideas at rebertia.com> wrote:
> On Tue, Jul 14, 2009 at 8:50 PM, George Sakkis<george.sakkis at gmail.com> wrote:
>> On Tue, Jul 14, 2009 at 3:16 PM, Paul Moore<p.f.moore at gmail.com> wrote:
>>
>>> 2009/7/14 Chris Perkins <chrisperkins99 at gmail.com>:
>>>>
>>>> y = sorted(x, key=&) do(item):
>>>>    name = item.split('-')[1]
>>>>    return name.upper()
>>>>
>>>> I think that forcing that two-line block of code to have a name would
>>>> serve no purpose - it's abundantly clear what it does.
>>>
>>> That's a very telling statement. To me, that code is utterly baffling.
>>> (Seriously! Without analysing it line by line, it means nothing to
>>> me).
>>
>> Seconded, there's too much going on ('&', what's "do", a function ?,
>> what's "item" ?, etc.). FWIW the only readable suggestion for
>> multiline lambdas with almost zero learning curve I have seen is the
>> one implemented in Boo, anonymous def and regular indentation:
>>
>> y = sorted(x, key=def (item):
>>                               name = item.split('-')[1]
>>                               return name.upper()
>>               )
>>
>> There must be somewhere posted the reason this was rejected but my
>> google-fu is failing me.
>
> IIRC, it screws with the essential statement-expression dichotomy of Python:
> http://unlimitednovelty.com/2009/03/indentation-sensitivity-post-mortem.html

Thanks, this was it. The important part is Guido's quote "any solution
that embeds an indentation-based block in the middle of an expression
is unacceptable", so it's basically a design judgement, not an
implementation constraint.

George