More power to Code Fields (was: Add "Hidden" region to get fields built but not displayed)

Problem

When using Code Fields we have very few options and variables to play with: global $conf, current $theme and $entity which was not 'viewed' and thus - w/o renderable array for itself and fields. So its no so much we can do and we have no access to already built fields.

Soluition

First - expose $build to Code Fields.

It is very simple fix, which brings power to Code Fields. All we need is $build array where all the stuff are ready to reneder.

Second - hide fields which are printed from a code field

If a field is not added to a region - it won't be built. So we should first add a field to some region and then use it in the code field. But in this case a field will be displayed twice! So we need a way to hide fields.

Previously I was trying to use some fields in code and came up to this solution. I don't like it anymore. Reason - hiding a field in this way will hide it in code field also :) So we either get duplicates or nothing.

Another approach is to add a special region "Hidden" which name is self explaining - you just put some fields into there and - TADA - they are built, configured and ready to print, but are hidden until you output them from the code.

Implementation

Patch provided.

How to use it

1. Place a field into region Hidden
2. Now in a code field you can:

Render everything:

  print render($build);

Render a field:

  print render($build['field_photo'][0]);

Use field values or field view:

  print l(render($build['field_photo'][0]), $build['field_link']['#items'][0]['display_url'], array('html' => TRUE));

Note, that taking field values from $build array is much more straightforward:

  print $build['field_link']['#items'][0]['display_url'];

then using $entity:

  print $entity->field_link['und'][0]['display_url']; 

because you got rid of calculating language code.

P.S. Adding $build called for changing functions arguments, and to not break existing stuff (which probably call ds functions directly) I added default values like: $build = array().