[Python-ideas] Dollar operator suggestion

[Thomas Jollans]

On 2017-10-26 13:06, Yan Pas wrote:
> I've looked up this feature in haskell. Dollar sign operator is used to
> avoid parentheses.
> 
> Rationalle:
> Python tends to use functions instead of methods ( e.g.len([1,2,3])
> instead of [1,2,3].len() ). Sometimes the expression inside parentheses
> may become big  and using a lot of parentheses may tend to bad
> readability. I suggest the following syntax:
> 
> len $ [1,2,3]

I see absolutely no benefit adding this syntax when we already have a
perfectly good function calling syntax.

> 
> Functions map be also  chained:
> 
> len $ list $ map(...)

Function composition has been discussed at length in the past, e.g.
https://mail.python.org/pipermail/python-ideas/2015-May/thread.html#33287

I'd like to highlight one key message:

https://mail.python.org/pipermail/python-ideas/2015-May/033491.html

Guido van Rossum wrote (May 11, 2015):
> As long as I'm "in charge" the chances of this (or anything like it) being
> accepted into Python are zero. I get a headache when I try to understand
> code that uses function composition, and I end up having to laboriously
> rewrite it using more traditional call notation before I move on to
> understanding what it actually does. Python is not Haskell, and perhaps
> more importantly, Python users are not like Haskel users. Either way, what
> may work out beautifully in Haskell will be like a fish out of water in
> Python.
> 
> I understand that it's fun to try to sole this puzzle, but evolving Python
> is more than solving puzzles. Enjoy debating the puzzle, but in the end
> Python will survive without the solution.


That old python-ideas thread could be of interest to you.

Best

Thomas