Re: [VOTE] Combined Comparison (Spaceship) Operator

From: Date: Mon, 02 Feb 2015 16:35:29 +0000
Subject: Re: [VOTE] Combined Comparison (Spaceship) Operator
References: 1 2 3 4  Groups: php.internals 
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Hey Nikita,

> On 2 Feb 2015, at 16:32, Nikita Popov <[email protected]> wrote:
> 
> On Mon, Feb 2, 2015 at 4:27 PM, Andrea Faulds <[email protected]> wrote:
> Hey Nikita,
> 
> > On 2 Feb 2015, at 13:49, Nikita Popov <[email protected]> wrote:
> >
> > I've voted -1 because I think this should be a function and not an operator.
> > compare($a, $b) is more obvious than $a <=> $b and it's not like writing comparison
> > functions is such a super common use case that it needs the extra brevity of an operator. A function
> > can furthermore be used as a callback, while an operator requires a wrapping closure.
> 
> There’s no actual use for the bare comparison operation as a callback, though: usort($foo,
> ‘compare’); would just be a slow version of sort($foo);
> 
> It may not be applicable to a direct sort() call, but it's useful for higher level APIs.
> With a function you can create APIs of the form function foo(..., $comparator =
> 'compare') { ... }, which will default to the "standard" comparison
> function without having to specially handle it all over the place.

Yes, that’s true.

I’d previously suggested adding a function to get a closure of an operator. But actually, perhaps
we should just follow PHP’s traditional string typing of callables, and make ‘+’, ‘-‘,
‘<‘, ‘<=>’ etc. be valid callables?

Thus:

    function doesThing($a, $b, callable $callback = ‘+’) {
        return $callback($a, $b);
    }
    doesThing(1, 2); // 3

Thoughts?

(I realise this is slightly OT.)

--
Andrea Faulds
http://ajf.me/






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