3 Common Features

3.8 Performing operations on selected objects

In any tool, there are a number of operations which you can perform on the selected objects, irrespective of which objects you have selected. This allows you to perform some powerful operations and also ensures a consistent feel to every tool in the environment.

In this context the term "selected objects" is meant in the widest sense, and can refer to any items selected anywhere in a tool, be it in a list of items, or a graph. It can also refer to the tool's current object: that is, the object which is currently being examined.

These operations are available throughout the environment, and are referred to as standard action commands. Most tools have several menus in which the standard action commands appear, and each menu allows you to operate on objects at different levels. The objects which are operated on by a given command depend on the menu from which you chose the standard action command.

As a more concrete example, consider the inspector, which is a tool to let you examine the contents of Common Lisp objects.

The standard action commands are present in two menu in the inspector: the Object menu, and the Slots menu.

Notice that in the first case, the object being operated on is the tool's current object: you do not have to take any further action before performing the operation.

In the second case, the objects being examined represent more specific pieces of information: you need to select them before you can perform the operation. This, therefore, examines more discrete pieces of information about the current object.

In general, any tool has at least two menus like those described above. The first operates on the current object. What that object is, and hence the name of the menu in which the commands are to be found, depends on the tool you are using. For instance, if you are examining classes, the commands can be found in a Classes menu. If you are examining symbols, they can be found in a Symbols menu.

The standard action commands in the second menu let you operate on the items currently selected in the description area of a tool. Again, the name of the menu depends on the kind of item that is selected.

Some tools may contain more than two such menus; precise details are given in the relevant chapters.

As a guide, if a menu has a plural for a name, the commands in that menu can be performed on multiple selections. If the menu name is not pluralized, commands only affect a single selection. Thus, commands in a Symbols menu could be performed on several selected symbols, and commands in a Symbol menu could only be performed on a single selection.

3.8.1 - Operations available

Common LispWorks User Guide, Liquid Common Lisp Version 5.0 - 18 OCT 1996

Generated with Harlequin WebMaker