Re: [RFC] [DISCUSSION] Scalar Pseudo-type

On 26 December 2017 18:35:29 GMT+00:00, "lists@rhsoft.net" <lists@rhsoft.net> wrote: > > >Am 26.12.2017 um 19:18 schrieb Larry Garfield: >> If I may, I think the argument has always been that >> >> 1) Foo & Bar makes total sense >> 2) int|float makes total sense >> 3) int & string is illogical so wouldn't matter anyway > >not true > >function x(int|string $x) >{ > $x = (int)$x; >} I think there's a misunderstanding here. Some previous proposals for "union types" also included "intersection types", so that you could assert "parameter must implement both of these interfaces". So 'Foo|Bar $x' would mean '$x instanceof Foo || $x instanceof Bar' and 'Foo&Bar $x' would mean '$x instanceof Foo && $x instanceof Bar'. I presume that's what Larry means by "int & string is illogical", because it would translate to "is_int($x) && is_string($x)", which is false for all values of $x. This is different from "int | string", which, as you say, might have valid uses. Regards, -- Rowan Collins [IMSoP]