On 4/14/2016 9:25 PM, Fleshgrinder wrote:
> On 4/14/2016 8:59 PM, Stanislav Malyshev wrote:
>> Hi!
>>
>>> I don't know what is complicated about "string|Stringable" or "Foo|Bar"
>>> since it is super self-explanatory. However, I find myself checking the
>>
>> It may be self-explanatory for you. It's much less self-explanatory for
>> somebody just starting to learn. It is also very dangerous - if it's
>> either Foo or Bar, can you call Foo::stuff on it or not? If it's string
>> or not string, can you call strlen on it? Etc., etc. It adds a lot of
>> cognitive load and complicates the whole picture. You may have a
>> specific use case where it is useful (which we have yet to see btw) but
>> please remember it's a language with literally millions of use cases and
>> users.
>>
>
> Reduce assertions*, enhance self-documentation, making code more robust,
> perform checks in the VM and not in userland, ...
>
> function fn($arg) {
> assert('is_string($arg) || method_exists($arg, "__toString")');
> }
>
> interface Stringable {
> function __toString(): string;
> }
>
> function fn(string|Stringable $arg) {
> // :)
> }
>
> You can find more information on the topic here:
>
> https://en.wikipedia.org/wiki/Tagged_union
>
> * Assertions in PHP are very error prone if combined with refactoring
> due to the fact that one should enclose the actual assertion in a string.
> Oh oh oh, I forgot the very important unions *int|string* and *float|string* for overflows as one can encounter them from time to time; even in native code. -- Richard "Fleshgrinder" Fussenegger
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