Re:Whats New in PHP 8.2
by steve_adams_86 on Monday April 25, 2022 @10:56AM
(#31155760)
This works fine in TypeScript. You can specify a type as boolean, true, or false, and it works exactly as you’d expect. I don’t see an issue with doing the same in PHP
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Introducing `false` as a standalone type but not `true` is what makes this weird. Generic, literal returns are fine. Python is another language that has it [1].
The introduction of the RFC [2] also still mentions `false` is of type bool:
> null corresponds to PHP's unit type, i.e. the type which holds a single value. false is a literal type of type bool.
But why call it bool if `true` is not a standalone type too?
[1] https://docs.python.org/3/library/typing.html#typing.Literal
It would not surprise me any to have a Boolean type and have both true and false as restricted subtypes of that. However, in this case of it being used primarily as a return type for failure in a function call, I think they're conflating the tradition from C-style languages of returning a false-ish value in-bound rather than creating a type specific to the error condition.
> I think they're conflating the tradition from C-style languages of returning a false-ish value in-bound
It’s not really conflation when php has been doing that since forever as it originally was little more than a thin shim over C (you can see that in lots of older APIs e.g. the mysql_ stuff is straight transcribed from the C library).