Re: RFC Proposal - Types for Inline Variables

On Tue, Feb 7, 2023 at 10:21 PM Mark Baker <mark@demon-angel.eu> wrote: > On 07/02/2023 20:53, Olle Härstedt wrote: > > No not really. I'd expect it behave similar to function argument > > type-hinting in PHP, that is, runtime checks, but where the notation > > can be used by external tools. > > The big difference is that the current checking for function arguments > is only necessary when a function is called; but that checking for > local-scoped variables would be required on every assignment to a > variable, or operation that can change a variable value; and that > becomes more problematic with the potential need for union types. > > Hi Mark, I saw that you and Olle were discussing that type checking should be similar with functions typed parameters . But in reality, it should be implemented more like typed properties. Actually that's already possible with something like https://3v4l.org/T6GFS function &declare_int(int $value) { static $references = []; $valueWrapper = new class(5) { public function __construct(public int $value) { } }; $references[] = $valueWrapper; return $valueWrapper->value; } $intVariable = &declare_int(0); $intVariable = 42; // works $intVariable = 'test'; // fails Even the PHP_INT_MAX works (it fails). To give credit, I saw it discussed few years ago on twitter and here you can see a nice playground implementation: https://github.com/azjezz/typed/ I don't see a bug technical performance downside, other than the wrapper class references that you need to have a management for. I think an implementation in C would be not less performant than how properties types are checked. Regards, Alex