Re: Proposal: AS assertions

On Fri, Mar 22, 2024 at 10:31 AM Jordi Boggiano <j.boggiano@seld.be> wrote: > > On 2024-03-21 16:02, Robert Landers wrote: > > $a as int|float > > would be an int, float, or thrown exception. > > $a as int|float|null > > would be an int, float, or null. > > Just a suggestion here which might be more palatable to Rowan's wish for consistency > (which I can totally relate to): > > We perhaps could make sure that as does not throw if used with > ??, or that ?? catches the type > error and returns the right-hand expression instead: > > So to do a nullable typecast you would do: > > $a as int|float ?? null > > To me this reads way more intuitive what will happen, and achieves the same in an also very > concise way. > > The only catch I see is that it would also swallow errors about $a not being defined at all. > > Best, > Jordi > > -- > Jordi Boggiano > @seldaek - https://seld.be Hey Rowan and Jordi, I did a bit of research into other languages to see how they handle "as": C#: as never throws, it either returns the type if it can be that type, or null OCaml: fails if an alternative isn't given Typescript: doesn't actually do anything, just hints the type for the compiler After asking an AI for some examples and usages, the most compatible one would be C#'s. In actuality, I think it could be hugely simplified if we simply return null instead of throwing. There'd be no special case for |null, and it would move the decision making to the programmer: $x = $a as int ?? throw new LogicException(); It also still allows for concisely making calls: $x = ($a as MyType)?->doSomething(); What do you think?