Defining the scope of rules

It is possible to provide rules that will apply to all things of one type, such as all the directory windows or all users of the system, by defining an appropriate rule clause in a system-wide module. More usually, you will want to limit the effect of your rules to certain icons, or certain users on the system. This is referred to as defining the ``scope'' of the rules.

Usually, the location of the file containing a rule determines its scope. For example, you can provide special behavior for one particular user by providing rule clauses in a suitable file in that user's home directory.

There are two essentially different ways of specifying the scope of a rule: ``implicitly'' and ``explicitly''. You can specify the scope implicitly by choosing the location of the file containing the rule. However, for icon_rules clauses you can also specify the scope explicitly, by specifying a pattern that matches the files or directories to which you want the rule to apply.

In some cases these methods of specifying the scope are interchangeable. For example, you could write a rule to apply to all the files in one directory using either of the following two methods:

• provide an icon_rules clause matching all files, and put it in a local rule file in the directory to be affected

• provide an icon_rules clause matching files with the appropriate pathname, and put it in a system-wide module or a user rule file

See also:

• ``Specifying scope implicitly''

• ``Specifying the scope explicitly''