On Wed, May 12, 2021, at 4:51 AM, Nicolas Grekas wrote:
> > > This makes me wonder: can we create a partial programmatically? Wouldn't
> > > that be needed for some use cases?
> > > Partial::createFromCallable($callable, the-args)?
> > >
> > > Nicolas
> >
> > I cannot think of a use case where that would be needed. Since you can
> > partial-ize any callable, including a dynamic one, if you needed to do
> > something like partial-ize one of a series of function calls you can do
> > that already:
> >
> > $c = match($some_input) {
> > 'A' => 'func_a',
> > 'B' => 'func_b',
> > 'C' => 'func_c',
> > };
> >
> > $p = $c(1, 2 ?, 4);
> >
> > Though at that point, just partialing them in the first place inside the
> > match would be better as then you never have a function name in a string to
> > begin with.
> >
>
> Here is a use case: high-order argument resolvers / function reducers.
>
> What I mean is a function that takes a callable as arguments, resolves as
> many args of the callable as it can using whatever logic fits, and returns
> a callable with fewer arguments (only the non-resolved ones - aka a
> Partial).
You're thinking something like an auto-wiring routine for callables?
function volume(int $x, int $y, int $z) { ... }
class Resolver {
private array $context = ['x' => 5];
public resolve(callable $c) {
foreach (get_argument_names_from_param($c) as $k) {
if (isset($this->context[$k]) {
$args[$k] = $this->context[$k];
}
}
return $c(...$args, ?);
}
}
$r = new Resolver();
$c2 = $r->resolve(volume(?));
print $c2(y: 3, z: 9);
I haven't tried running that (I don't feel like messing with the necessary
reflection), but... I think it would work already? Whether that's useful in
practice or not I don't know. :-)
--Larry Garfield
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