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Date: Thu, 10 Jun 2021 13:36:20 +0700
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To: Mike Schinkel <mike@newclarity.net>
Cc: Larry Garfield <larry@garfieldtech.com>, Nikita Popov <nikita.ppv@gmail.com>, 
	php internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Readonly properties
From: pierre.php@gmail.com (Pierre Joye)

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On Thu, Jun 10, 2021 at 11:08 AM Mike Schinkel <mike@newclarity.net> wrote:
>
> Hi Larry,
>
> Thanks for the response.
>
> > On Jun 9, 2021, at 12:51 PM, Larry Garfield <larry@garfieldtech.com>
wrote:
> >
> > Pierre and Mike:
> >
> > "Asymmetric visibility" as we keep referring to it would mean the
"implicit accessors only" version of this:
https://wiki.php.net/rfc/property_accessors
> >
> > That is, it would let you define public/private/protected for get and
set operations on a property separately from each other.
> >
> > There are three key differences between readonly and asymmetric
visibility as described there:
> >
> > * Asymmetric visibility would allow a property to be reassigned
multiple times from within a class, readonly would allow writing to it only
once when it's uninitialized.  Whether one of those is too-tight or
too-loose is a matter of opinion and context.
>
> When I read your statement I first thought you were wrong, but then I
re-read Nikitia's RFC[1] and realized that RFC stated the properties of an
object assigned to a readonly property *could* be updated, but *not* the
readonly property itself.

That's not related but an assignment by "reference" consequence. I think :)


>
> I wonder if I was the only one who read that mistakenly?
>
> Anyway, have either you or Nikita considered making a distinction between
'public readonly' and 'private readonly' such that one could disallow any
changes after initialization and the other could allow changes but only
within the class?

Better formulated than I tried :)

I would like to have the readonly keyword to make a property readonly
outside the class but read/write inside the class, together with
visibility it should cover pretty much all cases (parent class
included).

Init only could be a separate keyword (allows init only, inside the
class or outside the class being defined by the property visibility
attributes, protected, private or public).

I think users, and myself first when I read it, will have a hard time
translating "asymmetric...." part of this whole thing (as in, if one
has to go to wikipedia to understand what something does instead of
what it looks like ;) ).

best,

--
Pierre

@pierrejoye

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