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Date: Sun, 25 Apr 2021 09:19:43 +0200
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To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [PHP-DEV] [RFC][Draft] Sealed Classes
From: olleharstedt@gmail.com (=?UTF-8?Q?Olle_H=C3=A4rstedt?=)

> For a more typical PHP example, getUser(int $id) is not a total function,
> unless you have PHP_MAX_INT user objects defined in your database.  If you
> pass an int that does not correspond to a defined user, you now have to deal
> with "user not found" error handling.  getUser() is not a total function.
> getUsers(array $criteria), however, arguably is, because it's logical and
> reasonable to map all not-found cases to an empty array/collection, which
> doesn't require any special error handling.

getUser() could return a nullable type. But totality assumes purity,
and I'm assuming you didn't hard-code all users inside the getUser()
function. :) As soon as you interact with the outside world, you can
have exception and errors, and thus you can't guarantee termination.
In any case, I think the concept of totality is pretty foreign to PHP,
and we can probably leave it behind (you'd have to make sure -
statically, in the type-system - there are no infinite recursion, no
infinite loops, ...).

Olle