Re: pipes, scalar objects and on?

2023-07-18 14:48 GMT+02:00, someniatko <someniatko@gmail.com>: > I am glad this topic arose! I was also planning to write on this topic to > the internals mailing list, but have abandoned this idea, because I feel it > might be inconvenient for the real active PHP developers on the list to > receive too many emails from the people which don't actively participate in > the development itself. > > My interest in the pipe operator might seem a little non-standard - > basically what I'd really want to see is a **nullable** pipe operator! > > There is a popular library github.com/schmittjoh/php-option, which has 250 > MILLION installations. Basically what it provides is a class-wrapper of a > value of lack thereof: it's either Some<Type> or > None. I also maintain > a similar library > https://packagist.org/packages/someniatko/result-type > which fixes some shortcomings of the original one related to the static > analysis, but this is another story. Basically what the stats tell us is > that such stuff is popular among the PHP community. > > In my eyes, it is actually semantically equivalent to the nullable PHP > types: ?Type. And some operations provided by the lib, are > actually > covered by PHP itself, which has multiple null-friendly operators: > $option->getOrElse($defaultVal) --> > $nullable ?? $defaultVal > $option->isEmpty() --> $nullable === > null > $option->getOrThrow(new \Exception('blah')) --> > `$nullable ?? throw new > \Exception('blah')` > > I'd like to use the arguably "more idiomatic" native PHP nullables, rather > than a foreign-feeling userspace construct, if they were more convenient. > > But there is a very important operation, map(), which is > unfortunately > not covered by the native PHP, which is Option::map(), and here > is a > real-world example: > ``` > return $repository->getById($idFromHttpRequest) > ->map($serializer->serializeToJson(...)) // only executes when the > Option is Some, not None > ->map(fn (string $json) => new Response(status: 200, content: $json)) > ->getOrElse(new Response(status: 404)); > ``` Ehm, wouldn't that be the same as a Pipe class that's configured to stop on null? public function getThing($id) { return new Pipe( $this->getData(...), $this->serializeData(...), $this->mapToResponse(...) ) ->stopOnEmpty() ->from($id) ->run(); } Wait, are you using map() for arrays or not? Looks like not. Olle