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Date: Fri, 03 Jan 2020 10:53:09 -0600
To: "php internals" <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Initializing constants once, with code?
From: larry@garfieldtech.com ("Larry Garfield")

On Thu, Jan 2, 2020, at 6:39 PM, Mike Schinkel wrote:
> > On Jan 2, 2020, at 7:09 PM, tyson andre <tysonandre775@hotmail.com> =
wrote:
> >=20
> >> The problem with using constants is that the value is still hardcod=
ed
> >> and if we later want to change to pulling the data from a config fi=
le=20
> >> we have to change all the code that uses those constants.=20
> >=20
> > It's possible to work around this by using a unique constant name
> > and define('unique_name', $dynamicExpression)
> > (and const MY_CLASS_CONST =3D \unique_name;)
>=20
> I do appreciate the attempt to come up with something that is a workar=
ound.
>=20
> That said, I definitely do not want to do is start using "clever" code=
=20
> in my implementations because =E2=80=94 one day =E2=80=94 someone else=
 will have to=20
> maintain what I write.
>=20
> Really, I was just asking for a discussion of potentially allowing for=
=20
> one-time initialization via code for constants and via a=20
> straightforward, obvious syntax and standardized syntax. =20
>=20
> Effectively I am just asking for immutable static values in a class=20=

> that can be access vis the <Class>::<ImmutableValue> syntax.
>=20
> -Mike

I agree with the use case, but not with the solution of piggybacking the=
m onto constants.  It seems to me it would be much cleaner to just... bu=
ild that into a static method call with the derivation-and-caching logic=
 behind the scenes.  It's not complicated code.

class Stuff
{
  protected $val;

  public static function val() {
    self::$val ??=3D computeStuff();
    return self::$val;
  }
}

Although property accessors might make it even nicer looking, if we can =
ever figure out how to make that performant. :-)

--Larry Garfield