Using variable_get() in multiple places, without duplicating $default

Question

When using variable_get() in multiple places, how should one avoid duplicating the $default values?

define()? Or is there some built-in Drupal-specific mechanism I'm missing?

Answer 1

There is no built in mechanism. In fact, there is a long standing issue to add one http://drupal.org/node/145164.

Defining constants, as you suggested, is the only method I've seen to make it a bit cleaner.

Answer 2

A pattern that I often use in custom code, uses OOP. I use this for variable_get, t() and "magic" numbers such as the amount of items in a pager- or limit-query:

class MyModuleHelper() {
  public static $foo = "bar";

  public function v($name) {
    return variable_get("mymodule.{$name}", $$name);
  }

  public function t($identifier, $params) {
    $translated = "";
    $callback = "t_{$identifier}";
    if (function_exist($callback, $this)) {
      $untranslated = $callback();
      return t("mymodule." . $untranslated, $params);
    }
    return $translated;
  }

  private function t_thank_you() {
    return "Thank you, %username";
  }
}

Then, in the module:

  $helper = new MyModuleNameHelper();

  print "Variable foo:" . $helper->v("foo")
  print "Translate thank_you:" . $helper->t("thank_you")

This has several advantages:

• Your variables and translations are properly prefixed with mymodule., whithout duplicating that prefix all over the place (DRY!).
• No need to duplicate your strings and variable values all over the place (DRY+)
• No need to abuse constants for variable defaults. Constants are constant and should not be abused as value in a variable.
• Translatable strings are callable with a symbol, t("thank_you") instead of t("Thank you, %username").

And one downside:

• It is OOP and therefore "un-Drupal-ish".