Stan Vassilev | FM wrote:
Hi,
Multiple namespaces per file were introduced to allow certain workflows in PEAR
and frameworks like Symphony which can combine multiple classes and namespaces
in a single package.
They work like this:
namespace X;
...
namespace Y;
...
The problem is, no one thought of scoping "use" statements, so now those merged files
share their "use" imports, thus breaking all the code where collisions occur.
Also we have the problems with name resolution of internal vs user classes and
autoloaders, discussed here.
And we also have the non-intuitive differentiation between resolving
functions/classes/constant which will most likely lead people to believe
functions/constants aren't supported in any way in namespaces (if they try, and
it doesn't work, they won't try second time).
Which leads me to the following proposal:
For PHP 5.3 we introduce namespaces with a very limited "safe" set of barebones
features, that we won't regret later for releasing and having to modify in a non-BC way.
It'll let people start porting their code and be ready for the full featureset later on,
which will be a proper superset of the 5.3 release:
1) We disable support for multiple namespaces per file as it is, as it can't be used
without ability to scope "use" statements as well.
2) We remove the statement "use" (regarding namespaces, not regarding
closures), until we get more feedback from the community on the exact preferred
resolution algorithms, and more thought is put to this.
For PHP 5.4 or 6:
1) Introduce file-level "use" statements with same syntax as now, but modified resolution
rules based on further discussion and feedback. And if someone is about to say "we had plenty
of discussion", well it's apparent we didn't have enough given all the problems facing
namespaces right now, or maybe not enough of the constructive type of discussion.
2) Introduce ability to scope "use" and "namespace" statements with curly
brackets, so that multiple files can be safely merged without changing intent (all file-level
namespace can be converted with curly brackets, and the existing curly bracket ones don't need to
be converted), example:
namespace X {
use Y as Z {
...
}
}
namespace Y {
use X as Z {
...
}
}
Waiting for your feedback...
Regards,
Stan Vassilev
Again, some more 2 cents from me.
I'm not sure if this has already been decided but I agree with multiple
namespaces per file. Just seems like a good practice for large
frameworks. And I'm leaning towards +1 on NON-brackets for namespaces.
With multiple namespace declarations in one file the way it is now,
brackets seem un-needed.
As far as the scope of "use" in a multi-namespace file:
Considering that in a multi-namespace file, a namespace declaration ends
the previous namespace and begins the new one. Can the scope of the
"use" statement be whatever namespace declaration it is in? Ex:
<?php
namespace X;
use A::B as Z;
Z::func(); // Is really A::B::func()
namespace Y;
use C::D as Z;
Z::func(); // Is really C::D::func()
?>
There are a couple benefits with this way:
1. If multiple namespaces have the exact same use statements, they won't
conflict. Because the scope of use only applies the current namespace
declaration.
2. Merging multiple files is easier. Before the files are merged, the
developer would probably be testing their framework. This means that the
separate files have use statements in each one. When merging them all
together, the use statements won't conflict.
I agree that if use does not have a scope, it would become confusing. If
there wasn't, what would happen when there are two exact same use
statements. Or, if use statements point to different namespaces but have
the same name.
Another question when merging multiple files, is it ok to declare the
same namespace multiple times? If I were to merge files, I would just
append them all to one file.
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: http://www.php.net/unsub.php
