[Python-ideas] Dollar operator suggestion

Rhodri James rhodri at kynesim.co.uk
Thu Oct 26 07:47:44 EDT 2017

On 26/10/17 12:06, Yan Pas wrote:
> I've looked up this feature in haskell. Dollar sign operator is used to
> avoid parentheses.

If I understand your example correctly, it does no such thing.  "A $ B" 
appears to mean "apply callable A to object B", at least the way you 
portray it below.  I don't speak Haskell so I can't comment on the original.

> 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.

If you have that sort of legibility problem, it suggests that you are 
trying to do far too much on a single line.  New syntax won't help with 
that (in fact it will make it worse IMHO).

> I suggest the following syntax:
> len $ [1,2,3]

How is this better or easier to read than "len([1,2,3])" ?

What do you do for functions with two or more arguments?  The obvious 
thing would be to make the right-hand side of the $ operator a tuple, 
and whoops, there are your parentheses again.

I don't think this proposal achieves your aim, and I dislike it for a 
lot of other reasons.

Rhodri James *-* Kynesim Ltd

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