Creating a new Rules condition

This screencast shows how to create a new condition for the Rules module. It also touches on putting code in include files, to have it loaded only when needed.
Finally, this screencast also mentiones what I call "the Drupal effect": that you can spend a lot of work in Drupal to do a little, and a little work to do a lot.

code added to wordlist.rules.inc

/**
* Implements hook_rules_condition_info().
*/
function wordlist_rules_condition_info() {
$conditions = array(
'wordlist_condition_words_in_text' => array(
'label' => t('Any of words is in text'),
'parameter' => array(
'long_text' => array(
'label' => t('Text to investigate'),
'type' => 'text',
),
'list_of_words' => array(
'label' => t('List of words'),
'type' => 'list',
),
),
'group' => t('Word list'),
),
);

return $conditions;
}


/**
* The condition callback for wordlist_condition_words_in_text.
*/
function wordlist_condition_words_in_text($long_text, $list_of_words) {
// Loop through all the given words, return TRUE if the word is found.
foreach ($list_of_words as $word) {
if (stristr($long_text, $word)) {
return TRUE;
}
}

// If we've gotten this far, none of the words are present. Return FALSE.
return FALSE;
}