[development] module_exists vs. functions_exists?

[Darth Clue]

Earnie Boyd wrote:
> I would rather ask the interacting modules to insert a 
> MODULE_FOO_VERSION and check for the constant being defined and 
> defined to the version you expect.  The module_exists function used 
> with function_exists as you suggest is a good fall back for not having 
> MODULE_FOO_VERSION.
Agreed.  I recently had an issue where a module I depended on was 
upgraded and this resulted in my module failing.  Being able to specify 
that I was expecting a specific version of the module would have helped 
troubleshoot the issue alot quicker.

Jonathan