Re: bikeshed: Typed Aliases

On 09/09/2024 19:41, Mike Schinkel wrote:

Referencing prior art (e.g. Go) PHP could allow int literals — e.g. 1, 47, etc. — to be passed to typedefs derived from ints but require int variables to be typecast to the required type. Same for string literals.

That's an interesting compromise, worth considering.

In Go you cannot add or subtract on a typedef without casting to the underlying type. I would definitely prefer that to be relaxed, but only if it is relaxed via an explicit opt-in, e.g. something maybe like this: typedef UserId: int operations: +, -, *, /; typedef UserName: string operations: .;

I think this would stray into some of the same complexity as operator overloads on objects, in terms of the types and values allowed. For instance: typedef Metres: int; assert( Metres(2) +  Metres(1) === Metres(3) ); // most obvious assert( Metres(2) + 1 === Metres(3) ); // seems pretty clear $_GET['input'] = '1'; assert( Metres(2) + $_GET['input'] === Metres(3) ); // might be more controversial typedef Feet: int; assert( Metres(2) + Feet(1) === Metres(3) ); // almost certainly a bad idea Not unsolvable, but probably enough scope for nuance and debate that it should be left well into Future Scope.

type MyNewType: Foo type MyAlias = Foo

I know this was only an example, but as a general point, I think we should avoid concise but cryptic differences like this. PHP is generally keyword-heavy, rather than punctuation-heavy, and I think that's a valid style which we should keep to. -- Rowan Tommins [IMSoP]