Re: Proposal: AS assertions

On Fri, 22 Mar 2024, at 17:38, Claude Pache wrote: > >> Le 22 mars 2024 à 16:18, Rowan Tommins [IMSoP] <imsop.php@rwec.co.uk> a écrit : >> >> $optionalExpiryDateTime = $expiry as ?DateTimeInterface else some_other_function($expiry); >> assert($optionalExpiryDateTime is ?DateTimeInterface); // cannot fail, already asserted by >> the "as" > > I think that the is operator is all we need; the > as operator adds syntax complexity for little gain. Compare: > > $optionalExpiryDateTime = $expiry as ?DateTimeInterface else some_other_function($expiry); > > vs > > $optionalExpiryDateTime = $expiry is ?DateTimeInterface ? $expiry : > some_other_function($expiry); I agree, it doesn't add much; and that's what the draft RFC Ilija linked to says as well. But the point of that particular example is that after the "is" version, you don't actually know the type of $optionalExpiryDateTime without looking up the return type of some_other_function() With the "as" version, you can see at a glance that after that line, $optionalExpiryDateTime is *guaranteed* to be DateTimeInterface or null, which I understood to be the intention of Robert's original proposal on this thread. -- Rowan Tommins [IMSoP]