Useful functions[drupal]

drupal_parse_info_file($filename)

system_settings_form($form)

node_get_types($op = 'types', $node = NULL, $reset = FALSE)

drupal_get_path($type, $name)

drupal_get_form($form_id)

variable_set($name, $value)
variable_get($name, $default)
variable_del($name)

MENU_NORMAL_ITEM
MENU_CALLBACK
MENU_SUGGESTED_ITEM
MENU_LOCAL_TASK
MENU_DEFAULT_LOCAL_TASK