[development] Drupal 6.2 theme system standalone

[Bob Pepin]

On Sat, Jun 14, 2008 at 07:14, Larry Garfield <larry at garfieldtech.com> wrote:
> On Friday 13 June 2008, Bob Pepin wrote:
>> btw, drupal isn't perfect either, just earlier I spent fifteen minutes
>> hunting a bug just because I dared to create a variable called $theme
>> in some toplevel code.. turned out that global was already taken by
>> the drupal theme system, which apparently doesn't bother too much with
>> error checking, so all I got was a blank page, no error message, no
>> nothing.. of course PHP isn't completely innocent in this either ;)
>
> Creating a global variable in the first place was your first mistake.  They
> are a design flaw by definition for exactly the reason you describe.
> Creating one that was not namespaced to your module was mistake #2, for the
> reasons you describe. :-)

Well, since PHP does have neither namespaces nor modules (okay, you
can use classes as some kind of poor man's namespaces if you don't
mind writing ClassName::function() all the time), mistake #2 was
unavoidable ;)

My point though was that $theme is not exactly the ideal name for a
global variable used inside a library. But since the library I'm
talking about was previously simply a little module living in its
little closed drupal world, I can understand why it turned out the way
it did.

> You cannot really error check globals in that way, which is part of the
> problem with them.

Well in this case $theme was an instance of one of my own classes,
whereas the library was treating it as a string. Something that in
most languages would've either been detected at compile time or would
have signaled an error at runtime instantly.

And for error checking globals in general, simply requiring variables
to be declared before use and signaling an error when a variable with
the same name already exists can prevent those conflicts (this would
work similar to how PHP prevents you from accidentally redefining a
function).
And then of course being able to create properly lexically scoped
variables (like the "let" keyword that exists in various languages for
example) would avoid the problem altogether.

Okay, enough off topic for today, have a nice weekend ;)

Bob