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In-Reply-To: <FAD3F09E-9712-4353-B5CC-AF635BF23B3E@joshbruce.dev>
Date: Thu, 16 Jul 2020 10:31:39 -0500
Cc: Larry Garfield <larry@garfieldtech.com>,
 php internals <internals@lists.php.net>
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To: Matthew Brown <matthewmatthew@gmail.com>
Subject: Re: [PHP-DEV] [RFC][Discussion] Objects can be declared falsifiable
From: josh@joshbruce.dev (Josh Bruce)


> On Jul 16, 2020, at 10:28 AM, Josh Bruce <josh@joshbruce.dev> wrote:
>=20
> https://wiki.php.net/rfc/objects-can-be-falsifiable =
<https://wiki.php.net/rfc/objects-can-be-falsifiable>
>=20
> Updates:
>=20
> - Open issues (outstanding questions/concerns) updated
> - Future scope
> - References now have links to original copies on GitHub (still =
updating 0002) - will be removed if accepted and implemented.
> - No violent opposition, but concerns - will be looking at how to =
implement (or set up implementing).
>=20
> All:
>=20
> Trying to let conversation flow w/o me; sticking to once a day batch =
updates. Let me know if you=E2=80=99d prefer something else - still =
learning the Roman-way. :)
>=20
> To Larry=E2=80=99s user example.=20
>=20
> With Falsifiable the User instance becomes more self-aware. =
__toBool(), which might be more for the object itself, other objects, or =
PHP itself through a universal, reserved API entry point (like other =
magic methods).
>=20
> Trying to make PHP fail gracefully more by adding to the ability of =
not returning null (or interacting with null - nullsafe, optionals, and =
so on).
>=20
> (Maybe that should be a table as well??)
>=20
> print null; // always succeeds despite being nothing - not a fatal =
error
>=20
> (bool) null; // always succeeds - always false
>=20
> (integer|float) null; // always succeeds - always 0
>=20
> (array) null; // always succeeds - always []
>=20
> (string) null; // always succeeds - always =E2=80=9C"
>=20
> null->someMethod(); // always fails - crashes app
>=20
> I was in the conversations leading up to null being able to handle =
this much interaction, part makes me go back to something talked about =
re new developers (paraphrased): It's frustrating to learn software =
development when it takes a lot to set up and with every turn you take =
your app crashes - people give up; so, PHP prefers failing gracefully =
over hard crashes.=20
>=20
> The only interaction on null that seems to fail outright (from =
personal experience) is trying to call a method because it=E2=80=99s not =
an object. (It doesn=E2=80=99t even fail the dread array-to-string =
conversion. lol)
>=20
>> I really appreciate any effort that can make PHP a more powerful =
language. However, for this item, I believe it will generate much =
greater cognitive complexity for new users (and I hate to assume that =
this is a problem, but we have to remember our roots).
>=20
> David: Completely agree on respecting new users and devs (see opening =
bit).
>=20
> I=E2=80=99m thinking right now, for me, it=E2=80=99s more about always =
being able to message the type you expect, even if false (in the =
abstract), while also letting PHP to interact automatically with it in =
the ways we have also become accustomed.=20
>=20
>> (bool) cast working together with __toBool() is a good one, but I =
think that it is being discussed in another topic.
>=20
> Was it an RFC or email??=20
>=20
> If email and within the last week or so, it might be this same =
conversation.=20
>=20
> Took a moment to evolve to this kinda hybrid approach. (In short, back =
to the original implementation, with a pretty different rationale.)
>=20
>> The other implication is that this is now possibly *not* a bug:
>>=20
>> if (!$foo) {
>> $foo->bar();
>> }
>=20
> Matthew: I can see that feeling like a bug, for me it would be a =
feature (can=E2=80=99t believe I just said that).=20
>=20
> Objects that return an abstracted (high-level) false, can tell me why =
(without blowing things up via fatal errors or added syntax and time of =
try-catch-throw or various permutations of optionals, which is possibly =
frustrating for new devs - possibly specific to the self-taught, it was =
for me back in the day - still don=E2=80=99t have the muscle memory for =
try-catch-throw and implementing errors).
>=20
> I can=E2=80=99t ask null any questions - it exists only in the mind =
(so to speak), but I can send messages to an instance that is abstractly =
false. (And remove all the null-checks and optionals from (at least) my =
code that uses it or wraps some package that doesn=E2=80=99t.
>=20
> My contract with a function call becomes: You will always get =
something of this type - period. Whether it=E2=80=99s the one you =
specifically wanted, that would be debatable, but it will be that type.
>=20
>> "Further, the union type bool|Falsifiable will be dynamically added =
at run time to any object implementing the reserved __toBool() method, =
which would allow stdClass() objects to be defined as Falsifiable also. =
"
>>=20
>> What's that about?
>=20
> Larry: Totally lifted from the Stringable RFC - lol: =
https://wiki.php.net/rfc/stringable =
<https://wiki.php.net/rfc/stringable> - string|Stringable
>=20
> And I don=E2=80=99t know of a way to add an interface to `new =
stdClass()` - but thought this might be a valid use case:
>=20
> $object =3D new \stdClass();
> $object->__toBool =3D function() {=20
>  return false|true;=20
> };
>=20
> if (! $object) {
>  // made it
> }
>=20
>> "(Including __construct() replacing old style constructors in PHP =
7.)" - __construct replaced old-style constructors in PHP 5. :-)
>=20
> Here=E2=80=99s where I got that from: =
https://www.php.net/manual/en/migration70.deprecated.php =
<https://www.php.net/manual/en/migration70.deprecated.php>
>=20
> Might have been tired when reading it. Are old style constructors =
still available at all in PHP 7 (just deprecated)?? Looking for when old =
constructors were removed - not just deprecated.
>=20
>> I think the truth tables have a formatting error; check the last line =
that goes wider than the rest.  Also, watch out for "smart quotes" in =
the string parts.  Also, YAY summary tables!
>=20
> Thanks for the table suggestion!=20
>=20
> Not sure I=E2=80=99m getting the same issue. If you mean the line that =
starts with =E2=80=9Crow 1=E2=80=9D - this is a different paragraph, not =
part of the table - its width is styled wider than the table. =
Margin-bottom is 1.5rem on paragraph - 0 on the table; so, they butt =
against one another.
>=20
> Is there a way to add an empty line (don=E2=80=99t recall seeing it in =
the wiki syntax)?? Or, are you noticing something else??
>=20
>> Let's not confuse Java nullable issues with PHP nullability, which is =
quite
>> healthy :-)
>=20
>=20
> Marco: To be fair, I don=E2=80=99t know anything about Java=E2=80=99s =
nullable issues - only PHP's. :)
>=20
>> BTW, I'm not saying you should pursue both RFCs or anything, that's
>> just a reference in case you are looking around how others did it.=20
>=20
> Marcio: Thanks for the example! I=E2=80=99ve never used a language =
that has this as a possibility by this type of implementation - Swift is =
capable by way of overloading operators (at least last I used it). =
Definitely would like more examples of languages that do something like =
this. (Links to those conversations to glean high-level concerns and =
possible problems might be helpful as well.)
>=20
> Definitely not looking to pursue both at this time as emptiness or =
nonzero is harder for me to justify to myself, much less the larger =
community - not that it shouldn=E2=80=99t happen.
>=20
> Cheers,
> Johs
>=20

Apologies: I was NOT in the conversations leading up to null=