>
> I believe the fancy academic name for what we're discussing here is
> "lenses", and I agree that they'd be very useful. I currently use a
> user-space wrapper like so:
>
> function prop(string $prop): \Closure
> {
> return static fn (object $o): mixed => $o->$prop;
> }
>
> function method(string $method, ...$args): \Closure
> {
> return static fn (object $o): mixed => $o->$method(...$args);
> }
>
> Which lets me do this:
>
> $parentNames = pipe($vals,
> amap(method('getParent')),
> amap(prop('name')),
> );
But I really don't like the stringy method and property names.
That sure does it, but not that type safe though.
The T_BLING (that is the only name I will allow for $$) marker has been
> discussed on and off a few times over the years, I think first in Sara's
> original pipes proposal many years ago. I was actually going to suggest
> the same in this thread before I saw you did. :-)
>
Yes I found it. Actually there were many discussions about it. I didn't
really went through them, but how had it never made through? (I'll take
time to read through ofc)
> More abstractly, $$ meaning "the only obvious value in context" has
> potential, but also risk, because "obvious" is not always obvious. I do
> think it's an area to explore, though, and would definitely help with
> functional style code that relies heavily on closures.
>
I'm not sure I understand how this could not be "always obvious". IF, -
let's say we stick to what hacklang has:
https://docs.hhvm.com/hack/expressions-and-operators/pipe - I think it's
farily straightforward
$a = $obj->getConfig()
|> array_map($foo => $foo->getId(), $$)
|> array_filter($foo => $foo !== "woof", $$)
|> $this->toResponse($bar, $$, $baz);
But to get back to the original topic: I think this is what you were
looking for.
Zoltán Fekete
