Hi:
On 14 Oct 2009, at 22:44, Tom Boutell wrote:
I'm very concerned about the practical consequences of introducing
traits without state.
Well, we have not found a sufficient design until now, which would fit
nicely into PHP from dynamic and simplicity perspective.
A. They could do this using static hashes in global variables or a
separate class. The result is a garbage collection failure as these
references to $this will never go away. Designed-in GC failures are
unacceptable post PHP 5.3.
Doing this would be less than advisable.
B. PHP allows you to define properties at runtime. That is, you can
write:
$this->title = 'my title';
Without declaring var $title; at the class level.
But PHP 6 seems to be moving toward more strictness, not less, and
this style encourages the use of undeclared variables with the
resulting potential for missed bugs.
Thats the currently preferred approach from my perspective.
The only thing you are going to lose here is a notion of separation of
state from different traits, compared to a language supported approach.
However, if you prefer to be more strict, it is still perfectly
possible to circumvent this problem by using getters and setters.
Also, the 'instead' keyword is baffling - it could mean replace A with
B or replace B with A depending on how you place your mental comma - I
much prefer the assignment syntax alternative, or 'insteadof' which is
unambiguous.
Yes, that was discussed before, but unfortunately did not make it into
the list of alternative syntaxes, will try to keep track of it.
Best regards
Stefan
On Wed, Oct 14, 2009 at 4:07 PM, Lukas Kahwe Smith
<m...@pooteeweet.org> wrote:
On 14.10.2009, at 22:03, Stanislav Malyshev wrote:
Hi!
So lets warm this up again.
HEAD is for development .. so lets get this into HEAD so that it
will be
part of the next bigger PHP release for sure!
Well, the code is sitting here
http://github.com/gron/php-src/tree/PHP_6-traits
and waits to be merged. :)
I thought before merging code it would be useful to have some
discussion
on if the code is actually doing what we want. If it's based on
http://wiki.php.net/rfc/horizontalreuse then for example I can see
some
potential issues for bytecode caching related to renaming and
changing
visibility.
Also, it is not clear that we want grafts there at all, some
aspects of
them seem to get too hairy, esp. $this issue or statics.
i think Stefan is fully aware of that probably there will be a
discussion
first ..
but i think we all agree that this feature is very high on the list
of what
people want and therefore i wanted to get this discussion going, so
that
after its concluded traits can be commited to HEAD.
regards,
Lukas Kahwe Smith
m...@pooteeweet.org
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Stefan Marr
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http://prog.vub.ac.be/~smarr
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