Plugin files and functions must follow a very specific naming
convention in order to be located by Smarty.
The plugin files must be named as follows:
Where type is one of these plugin types:
And name should be a valid identifier (letters,
numbers, and underscores only).
Some examples: function.html_select_date.php,
The plugin functions inside the plugin files must be named as follows:
The meanings of type and name are
the same as before.
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