+Type, +Default, +Comment)Define a setting. Name denotes the name of the setting, Type
its type. Default is the value before it is modified. Default
can refer to environment variables and can use arithmetic expressions as
defined by eval_default/4.
If a second declaration for a setting is encountered, it is ignored
if Type and Default are the same. Otherwise a
permission_error is raised.
|Name ||Name of the setting (an
|Type ||Type for setting. One of |
or a type defined by must_be/2.
|Default ||Default value for the
|Comment ||Atom containing a (short)
descriptive note. |