[Python-ideas] Thoughts on lambda expressions

[Ethan Furman]

Note:  Whatever fancy stuff you are doing to your messages is totally 
messing up trying to reply to you.

On 03/02/2016 04:19 PM, Abe Dillon wrote:

> Not only did you get the syntax wrong,

Ah, I see that I did.  Oops.

> but the lambda version is also
> horrid which is exacerbated by the fact that it looks like your trying
> to give the function a name or otherwise store it which defeats whole
> purpose of a lambda.

If I was giving it a name I would use `def`.  I am storing it, and that 
is a very common use of lambdas (to be fair, I stole one line from a 
multi-line dictionary definition).

> At that point just use 'def' and stop trying to use
> lambda where it is ill suited.

This is exactly where lambda is suited.

> the idea is from the recipe metaphor for a function:
>
> def <recipe>(<ingredients>):
>      ...instructions to cook ingredients
>
> vs.
>
>   (<make_something> from <ingredients>)

Huh.  Well, it looks good like that, but the actual examples were quite 
jarring to me.

> It's fair to quibble over the exact implementation (maybe use 'with'
> instead of 'from') but the main point of the syntax it to put the
> important bit (i.e.the expression) in front of the (usually) unimportant
> bit (i.e. the signature) and to swap out an esoteric word (lambda) with
> something that continues the readability emphasis of Python by using

Yeah, it would be better with `with`.  But, really, I don't see it 
happening -- the whole anonymous function thing is not encouraged, so 
making it easier is not a goal.

I wonder if MacroPy[1] would let you try it out?

--
~Ethan~

[1] https://pypi.python.org/pypi/MacroPy