[Python-ideas] + operator on generators

[Steven D'Aprano]

On Tue, Jun 27, 2017 at 11:01:32AM +0200, Stephan Houben wrote:
> Hi all,
> 
> Is "itertools.chain" actually that common?
> Sufficiently common to warrant its own syntax?

I think it's much more common than (say) sequence repetition:

a = [None]*5

which has had an operator for a long, long time.

> In my experience, "enumerate" is far more common
> among the iterable operations.
> And that doesn't have special syntax either.

True. But enumerate is a built-in, and nearly always used in a single 
context:

for i, x in enumerate(sequence):
    ...

A stranger to Python could almost be forgiven for thinking that 
enumerate is part of the for-loop syntax.

In contrast, chaining (while not as common as, say, numeric addition) 
happens in variable contexts: in expressions, as arguments to function 
calls, etc.

It is absloutely true that this proposal brings nothing new to the 
language that cannot already be done. It's syntactic sugar. So I guess 
the value of it depends on whether or not you chain iterables enough 
that you would rather use an operator rather than a function.

> A minimal  proposal would be to promote "chain" to builtins.

Better than nothing, I suppose.



-- 
Steve