Plugin files and functions must follow a very specific naming convention in order to be located by Smarty.
plugin files must be named as follows:
type is one of these plugin types:
name should be a valid identifier; letters,
numbers, and underscores only, see
plugin functions inside the PHP files must be named as follows:
The meanings of
the same as above.
An example modifier name
foo would be
Smarty will output appropriate error messages if the plugin file it needs is not found, or if the file or the plugin function are named improperly.