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Date: Thu, 1 Oct 2015 19:05:53 +0100
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Subject: Re: [PHP-DEV] Arrow function expressions in PHP
From: rowan.collins@gmail.com (Rowan Collins)

Levi Morrison wrote on 01/10/2015 18:38:
> Chain works is because the functions passed to it accept iterables as
> their only parameter and return either an another iterable or a
> reducing function (in this example sum is the reducer). This is why
> the functions are returning closures that accept only one parameter.

OK, that makes sense of one level of indirection. It doesn't however 
seem to justify the nesting in reduce()

If I understand correctly, your library obliges me to write this:

     $algorithm = chain(
         map(function($x) => $x * 2),
         reduce(0)(function($acc, $val) => $acc + $val)
     );
     $algorithm([1,2,3]);


But that seems to have no advantage over this:

     $algorithm = chain(
         map(function($x) => $x * 2),
         reduce(0, function($acc, $val) => $acc + $val)
     );
     $algorithm([1,2,3]);


Which would make the body of reduce significantly simpler, because it's 
just one named function accepting a closure, and returning a closure, 
with no further nesting.

The function chaining only appears to be useful if the closure returned 
by reduce(0) is to be passed or applied in some other way, and I can't 
think of when that would be required.

Regards,
-- 
Rowan Collins
[IMSoP]