During the Drupal 7 development cycle, we made a couple of changes to
theme functions, notably:
1. They now all take a standardized array of variables instead of an
arbitrary list of parameters (see http://drupal.org/update/modules/6/7#theme_changes)
.
2. When passing in a renderable element (such as forms, pages,
content, etc.), you can pass in parameters via #properties (see http://drupal.org/update/modules/6/7#poundtheme)
.
Unfortunately, these two changes clash with one another in the case
where you pass in a single non-renderable argument to your theme
function, and we didn't catch this until the couple days or so before
code freeze. It then took a few additional days to get an acceptable
fix together. (http://drupal.org/node/600974 if you're curious about
the backstory here.)
Therefore, we have the first of what is *hopefully* a very short
list ;) of Drupal 7 API changes post-code freeze. Please be advised
that if your D7 module defines a hook_theme(), you need to change it
in the following way:
1. Where you used to say 'arguments' => array('whatever' => NULL,
'whatever' => NULL), you now say 'variables' => array('whatever' =>
NULL, 'whatever' => NULL)
2. In the case where you're passing in a renderable element to your
theme function (such as the case of a form theme function), instead of
specifying it in the list of variables, you'll simply add: 'render
element' => 'form' and omit the 'variables' line altogether.
Sorry for the hassle, but believe me, this is a *much* better
situation than not being able to have theme functions with one
argument. :P And thanks so very much to those who've embraced #D7CX
and have started porting your modules already!
-Angie
