## 3.1 Overview

The online manual consists of a large set of tools to examine different aspects of the XPCE/Prolog environment and to navigate through the available material from different view-points.

The inheritance hierarchy (Browsers/Class Hierarchy)
  The `Class Hierarchy' tool allows the user to examine XPCE's class hierarchy. This tool reads the inheritance relations from the class objects and thus also visualises application or library classes. Figure 42 is created using this tool.
The structure of a class (Browsers/Class Browser)
  The most important tool is the `Class Browser'. It provides the user with a view of material related to a class. As everything in XPCE is an object and thus an instance of a class this tool provides access to everything in XPCE, except for the Prolog interface.
Search Tool (Browsers/Search)
  This tool provides full search capabilities on the entire manual contents, including combined search specifications.
Globally available object references (Browsers/Global Objects)
  The XPCE environment provides predefined objects (@pce, @prolog, @arg1, etc.). The tool allows the user to find these objects.
Prolog interface predicates (Browsers/Prolog Predicates)
  This tool documents all the XPCE/Prolog predicates.
Instances (Tools/Inspector)
  This tool is part of the runtime support system. It allows you to inspect the persistent state associated with objects.
Structure of User Interface (Tools/Visual Hierarchy)
  This tool provides a `consists-of' view of all displayed visual objects. It provides a quick overview of the structure of an interface. It is a useful for finding object-references, examining the structure of an unknown UI and verifying that your program created the expected structure.
The manual itself (help) (File/Help)
  The manual tools are documented by itself. Each tool has a `Help' button that documents the tool.
XPCE Demo programs (File/Demo Programs)
  The `Demo Programs' entry of the `File' menu starts an overview of the available demo programs. A demo can be started by double-clicking it. The sources of the demos may be found in `<home>/prolog/demo`, where <home> refers to the XPCE installation directory, which may be obtained using

      1 ?- get(@pce, home, Home).
      Home = '/usr/local/lib/pl-4.0.0/xpce'

  Note that the DemoBrowser allows to view the sources of the main file of a demo application immediately. Also consider using the VisualHierarchy and ClassBrowser to analyse the structure of the demo programs.