[Python-ideas] Thoughts on lambda expressions

[Ed Minnix]

Or, for those whose keyboards don’t allow them to efficiently type Unicode, something like a keyword ``it`` would be a good alternative. 

- Ed

> On Mar 2, 2016, at 6:14 PM, Grant Jenks <grant.jenks at gmail.com> wrote:
> 
> On Wed, Mar 2, 2016 at 3:02 PM, Ed Minnix <egregius313 at gmail.com <mailto:egregius313 at gmail.com>> wrote:
> Hi, I would just like to add a side note on this:
> 
> The library fn.py implements a class called _Callable, which gives a shorter notation for lambdas, using an underscore ( _ ), instead of declaring parameters (for example, map(_ + 1, range(10)) is the same as map(lambda n: n + 1, range(10)) ). In addition to the regular arithmetic operators, it supports the __getattr__ method. (for instance _.y is the same as lambda a: a.y)
> 
> Therefore, you do not override the general syntax of Python (other than the fact that you cannot use the code
> 
> for i, _ in some_iterable:               # don’t use, at the end of the loop, fn._ has disappeared from the scope of the module
>         do_something(i)
> 
> )
> 
> Personally, I would propose the adoption of the _ in some standard library module (e.g., functools) rather than overriding the “from” syntax if the simplification of lambdas in a goal. (Personal I find the _ much more user-friendly)
> 
> - Ed M
> 
> +1 for fn.py's underscore functionality.
> 
> But underscore already has a purpose as a placeholder and in the repl so I think it's a poor choice. In Python 3, you can actually do:
> 
> from fn import _ as λ
> print(sorted(cards, key=λ.suit))
> 
> But that is hard to type on most keyboards. What if we allowed question marks in identifiers and used ``?.suit`` ?
> 
> Grant
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20160302/934eba54/attachment-0001.html>