Joe Murray wrote:

I have a Drupal 5 cck type with a large text field that is not often populated. The column for that field in a view could have a link to view the node, and include the text in the field in a tooltip if it is non-blank, and otherwise not display anything to the user.

I think to implement this I want to provide custom theming of the field in views that will be invoked by theme_get_function http://api.drupal.org/api/function/theme_get_function/5: something along the lines of function tablename_fieldname(). Could anyone point me in the direction of code that does this kind of theming?

Sounds like your view is of type table. To custom theme the content of a column use a function template.php like:

function phptemplate_views_handle_field_node_data_FIELDNAME_FIELDNAME_value($fields, $field, $data)

This works for me anyhow. You may have to play with it to get the function name precise. To see this in the Views code, find function phptemplate_views_view_table and see the line:

$cell['data'] = views_theme_field('views_handle_field', $field['queryname'], $fields, $field, $node, $view);

See the code in theme_views_handle_field and you will see how the Views module looks for custom functions to replace the default ones.

HTH

Fred