[development] low hanging fruit for Drupal 6: variable defaults

[Gabor Hojtsy]

Gabor Hojtsy wrote:
> A follow up to this is an issue by dww: http://drupal.org/node/145164
> Although he reaches the conclusion that we need a hook_variable() from 
> another angle, the goal is the same after all. So people sympathizing / 
> against the effort, please use that issue!

And now Jose A. Reyero is at it, and proposing a nice patch, which has 
good performance and development-friendliness implications, so I would 
encourage people to go and review the patch:

   http://drupal.org/node/145164#comment-250759

Performance improvements:
  - slightly less code to parse on each page view, as variable defaults
    are centralized
  - less t() calls to invoke, as not close to every variable_default()
    call requires calling that, it only needs to be invoked at most
    one time for a value
  - less data to load in and unserialize from variable cache, as
    default values are not saved
  - less updates / cache refreshed on variables table because if
    value is unchanged it is not updated in database
  - less variables stored because uninstalled modules get their
    variables uninstalled automatically

Development convenience improvements:
  - no need to repeat variable defaults everytime
  - you get your variables removed on uninstall, no need to
    write code for that
  - because you provide a type for your variable in the variables
    hook, you have your common value types automatically validated
    (implemented for email addresses and numbers)

PLUS this makes it a lot easier to provide user friendly localization or 
translation features for site settings.

Gabor