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Date: Mon, 20 Apr 2020 10:15:40 -0500
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Mixed type
From: larry@garfieldtech.com ("Larry Garfield")

On Mon, Apr 20, 2020, at 9:15 AM, Sara Golemon wrote:
> On Mon, Apr 20, 2020 at 8:52 AM Larry Garfield <larry@garfieldtech.com>
> wrote:
> 
> > On Mon, Apr 20, 2020, at 6:17 AM, Dan Ackroyd wrote:
> > > Here is an RFC for adding a 'mixed' type to the language:
> > > https://wiki.php.net/rfc/mixed_type_v2
> > >
> >
> > I am not against this, but now that we have Union types what places are
> > there where the currently available type declarations are insufficient?
> > Resource seems like the only remaining gap where you'd be forced to use
> > `mixed` instead of a union.
> >
> > I imagine some type combinations get pretty wide. Like, this is verbose AF.
> 
> null|bool|int|float|string|array|object|resource

Sure, but how often is that an actual description of what the code accepts?  I... cannot actually envision what code would actually accept that mess. :-)

With union types and stringable already on the way, I'm not sure what other non-hypothetical use cases would still be that fugly that you'd now need to fall back to `mixed`.  (I still think intersection types are needed, but that's a separate matter.)  There may be, but I cannot think of them.

> For the long term good of the language I'd prefer type aliases (or typedefs
> or usings or whatever you want to call them.
> 
> use mixed = null|bool|int|float|string|array|object|resource;
> use scalar = null|bool|int|float|string;
> use number = int|float;

Concur.

> That said, baking 'mixed' in as an implicit alias of the above isn't
> problematic for that future.
> 
> -Sara

Concur.

--Larry Garfield