[development] module_exists vs. functions_exists?

[Larry Garfield]

Come Drupal 7, you'll want to use drupal_function_exists() specifically so 
that it can lazy-load the function if needed.  I suppose that's a strike in 
favor of using function_exists() for now so that your logic is already setup 
for that.

On Sunday 22 June 2008 4:36:46 pm Greg Knaddison - GVS wrote:
> Hi,
>
> In building some contrib modules that interact with other modules I
> often find myself writing something like:
>
> if (module_exists('module_name')) {
>   $foo = module_name_api_function($bar);
> }
>
> This seems to be pretty common across core and contrib.  I'd even call
> it standard.
>
> Another option would be:
>
> if (function_exists('module_name_api_function')) {
>   $foo = module_name_api_function($bar);
> }
>
> The benefit of the second format is that if/when module_name's
> maintainer decides to rewrite module_name and change all their
> functions then my module may simply stop interacting with it rather
> than failing on a function not found error.
>
> The benefit of the first format is that it fails quickly and is likely
> to generate a bug report with a very clear solution.
>
> Thoughts?
>
> Thanks,
> Greg

-- 
Larry Garfield
larry at garfieldtech.com