[Python-ideas] @return?

Wed Apr 14 20:54:59 CEST 2010

On 14 Apr 2010, at 20:41 , MRAB wrote:
> 
> Masklinn wrote:
>> On 14 Apr 2010, at 18:41 , Conrad Irwin wrote
>>> On 04/14/2010 03:54 PM, spir ☣ wrote:
>>>> On Wed, 14 Apr 2010 01:23:08 +0100
>>>> Well, i'm not 100% sure of the point of view below, but let's take the risk ;-) (Gentle)critics welcome.
>>>> 
>>>> As I see it, the issue you raise is more general than the precise point of a decorator's return value. It is instead deeply rooted in Python's core syntax making func/method  definitions (and classes, too) somewhat different. One doesn't write:
>>>> 
>>>> f = function(): <body>
>>>> 
>>>> So that one cannot write neither:
>>>> 
>>>> return function(): <body>
>>>> 
>>>> This point (together with the unneeded 'return' in this case) also raises the need for a special inline syntax for func defs used in higher-order functions --say for programming in functional style. This a bit of a pity because Python also offers a third syntax for similar semantics with list comprehensions.
>>>> 
>>>> As a counter-example just for reference, Lua's function defs are normal definitions, so that there are no such issues; "return function() <body>" is perfectly valid and even common; there is no need for special inline syntax.
>>>> But:
>>>> * An alternate pattern (function f() <body>) is available for named functions, while unnecessary (I personly never use it).
>>>> * Mainly because of the useless 'return', I guess, some users still argue for a more compact anonymous pattern.
>>>> 
>>>> 
>>>> Denis
>>> As I understand it, there is little desire to allow function definitions
>>> to appear "just anywhere" in Python.
>> I don't believe that's true, but it is possible that people who express
>> this desire are directed towards other languages.
>> I can only speak for myself when I say that I'd kill for full-fledged anonymous defs (uncrippled lambdas, whatever you call them) in Python,
>> but the desire is most definitely there.
> Part of the problem is finding a suitable syntax. Python's use of
> indentation makes it difficult, and we don't want to give that up, do
> we? :-)
Indeed, but there's no reason why it should be unsolvable, Haskell manages to have lambdas even using offside syntax (though it has a few properties which probably make it easier to handle than in Python)