Re: Why are the PHP namespaces different compared to C++?

On Thu, Sep 6, 2012 at 6:15 PM, Sherif Ramadan <theanomaly.is@gmail.com> wrote: > On Thu, Sep 6, 2012 at 5:30 PM, Mark <markg85@gmail.com> wrote: >> Hi, >> >> I was just using the PHP namespaces for the first time and noticed a >> difference that i really didn't expect. (No, i won't start complaining >> about the slash based namespace). >> >> In C++ when you type: >> using std; >> >> Then you can use all methods/classes/whatever is defined in std >> without typing std. >> so: std::cout becomes just cout. >> >> In PHP that's a bit different. Lets take this as an example: >> ================================= >> namespacetst.php >> >> <?php >> namespace Some\Long\Namespace; >> >> Class SomeClass >> { >> } >> >> >> Now the one using that "SomeClass" has to do something like this: >> index.php >> use Some\Long\Namespace; >> >> $oClass = new Namespace\SomeClass(); >> ================================= >> >> Yes, you can also do: >> >> index.php >> use Some\Long\Namespace\SomeClass; >> $oClass = new SomeClass(); >> >> But i'm wondering why the "use Some\Long\Namespace" doesn't work like >> the C++ one. Since i would have guessed that adding that use will give >> me access to all the methods/classes/whatever that live within that >> namespace _without_ having to prefix it with the last part of the >> namespace. >> >> I hope someone can shed some light over this. >> >> Regards, >> Mark >> >> -- >> PHP Internals - PHP Runtime Development Mailing List >> To unsubscribe, visit: http://www.php.net/unsub.php >> > > > Yes, PHP namespaces are completely different from what you'd be used > to in C++. In all honesty namespaces were never well designed in PHP > and were implemented in a haphazard way, which is why I generally > don't bother using them. > > To clarify, importing namespaces in PHP isn't like importing > namespaces in C++ at all, really. You are merely aliasing namespaces > in PHP when you use the "use" keyword. Meaning that what's actually > happening is PHP expects you to alias one namespace to another (and > thus you can never import one namespace directly into the existing > namespace since this creates a name conflict). It's messy... > > NameSpacedFile.php > namespace My\Name\Space; > class MyClass { } > > > Index.php > use My\Name\Space; // This doesn't actually import anything > // What happened here is we created an alias > // It's the same thing as saying "use My\Name\Space as \Space > // So now My\Name\Space is aliased to \Space > > $obj = new \Space\MyClass; // great > $obj = new MyClass; // this won't do what you want > > > Here's the full example: > > http://viperpad.com/qcAUNM > > It simply doesn't work like that because PHP's namespaces are > implemented in such a way that they don't really resemble namespaces. > Just some fancy magic going on in the engine that allow it to mimic > namespaces. While that is true, I cannot stress their importance in organizing code. Nearly every codebase I've seen that can use namespaces maps the namespace to the file system which makes for very easy-to-code autoloaders. Very helpful indeed. It would be nice to see improved namespaces, though.