Programming in XPCE/Prolog: Section 3.3

3.3 Guided tour

This section provides a `guided tour' through the manual system. If you have XPCE/Prolog at hand, please start it and try the examples. For each of the central tools of the manual we will present a screendump in a typical situation and explain the purpose and some common ways to use the tool.

3.3.1 Class browser

Figure 3 : The Class Browser

The ``Class Browser'' is the central tool of the online manual. It provides an overview of the functionality of a class and options to limit the displayed information. Figure 3 shows this tool in a typical situation. In this example the user is interested in methods dealing with `caret' in an editor.

The dialog to the left-side of the tool specifies what information is displayed. The top-right window displays the class together with the initialisation arguments (the arguments needed to create an instance of this class). Double-left-click on this text will open the description for ->initialise.

Below this text a hierarchy is displayed that indicates the place in the inheritance hierarchy as well as the classes to which messages are delegated (see section C.4). The user can select multiple classes only if there is delegation and the tree actually has branches. Use class editor or class view to explore these facilities. After the user has selected one or more classes, the Apply button makes the class-browser search for methods in all classes below the selected classes. If a method is found in multiple classes the class-browser will automatically display only the one method that will actually be used by this class.

The large right window displays a list of matching classes, variables, methods and class-variables. If an item is tagged with a ``(+)'' there is additional information that may be obtained by (double-) clicking the card to start the ``Card Viewer'' (see section 3.3.2).

3.3.1.1 The ClassBrowser dialog

The Class text_item (text-entry-field) may be used to switch to a new class. Note that this text_item implements completion (bound to the space-bar).

The Filter menu filters the candidate objects according to their categorisation. Selecting all switches off filtering, which is often useful in combination with Search. Clicking all again switches back to the old selection of categories. The meaning of the categories is:

Basic
Principal methods that are used very often. This is, together with Application, the default selection of this menu.
Advanced
Less often used and sometimes complicated methods.
Rare
Infrequently used methods. Note that does not mean they are complicated or do things you'd hardly ever want to use. For example, most of the caret-manipulation of class editor is in this category. It is essential and commonly used behaviour of the editor, but rarely used directly from program-control.
Internal
Behaviour that is not directly intended for public usage. It may be useful to understand how other methods interact. Try to avoid using these methods or variables in your code.
Basic OO
Methods intended to be redefined in user-defined classes. See chapter 7.
Advanced OO
Methods that may be redefined in user-defined classes, but for which this is far less common.
Application
Methods implemented in the host-language.

The Display menu determines the objects searched for. Self refers to the class itself, Sub Class refers to the direct sub classes of this class. The other fields refer to instance-variables, methods with send- and get-access and class-variables.

The Search and ... In controllers limit the displayed cards to those that have the specified search string in one of the specified fields. While searching, the case of the characters is ignored (i.e. lower- and uppercase versions of the same letter match). Searching in the Name field is useful to find a particular method if the name (or part of it) is known.

3.3.1.2 Example queries to the classbrowser

Below we illustrate how some commonly asked questions may be answered with the class browser.

What are variables of a bitmap?
Select variable in the Display menu, clear Search, and set Filter to All. Then type `bitmap' in Class and hit return. Note that by double-clicking on class graphical in the inheritance display not only the variables of class bitmap itself are shown, but also those of class graphical.
How can I position the caret in an editor?
The caret can only be changed using send-methods. Either the name or the summary is likely to have `caret' as a substring. Thus, Display is set to Send Method, Field to Name and Summary, search `caret'.

3.3.1.3 Methods with special meaning

This section describes the rol>

For example, the ->initialise method of a graphical text object has type declaration:

[char_array], [{left,center,right}], [font]

The first argument is an instance of class char_array, the super-class of name and string. The second argument either `left', `center' or `right' and the last argument is a font object. All arguments are between square brackets and may thus be omitted.

./usr/share/doc/swi-prolog-doc/UserGuide/sec-3.3.html0100644000000000000000000003341007426550346021110 0ustar rootroot Programming in XPCE/Prolog: Section 3.3

Basic
Principal methods that are used very often. This is, together with Application, the default selection of this menu.
Advanced
Less often used and sometimes complicated methods.
Rare
Infrequently used methods. Note that does not mean they are complicated or do things you'd hardly ever want to use. For example, most of the caret-manipulation of class editor is in this category. It is essential and commonly used behaviour of the editor, but rarely used directly from program-control.
Internal
Behaviour that is not directly intended for public usage. It may be useful to understand how other methods interact. Try to avoid using these methods or variables in your code.
Basic OO
Methods intended to be redefined in user-defined classes. See chapter 7.
Advanced OO
Methods that may be redefined in user-defined classes, but for which this is far less common.
Application
Methods implemented in the host-language.

3.3.1.2 Example queries to the classbrowser

Below we illustrate how some commonly asked questions may be answered with the class browser.

What are variables of a bitmap?
Select variable in the Display menu, clear Search, and set Filter to All. Then t