This document describes the use of the Inspector libraries for Mindy. The Inspector libraries are used to supplement the current Mindy debugger, and provide programmers with a tool for interactively inspecting their data structures. The Inspector has two separate interfaces, a text-based interface and a grpahical interface. The text interface is similar to that of Mindy debugger. The graphical interface offers a pleasant if uninspiring way of inspecting objects; it also offers a rudimentary class diagram viewer.
The Inspector is divided into three libraries, Inspector-Base, Text-Inspector, and X-Inspector. The first of these provides facilities that are common to the other two libraries. The Text-Inspector library implements a text interface to the Inspector and the function inspect. The X-Inspector library implements a graphical interface to the Inspector and the function xinspect. Use of the X-Inspector requires Dylan/TK, which may not available on all systems.
The Inspector is most often invoked via the inspect and xinspect debugger commands. These debugger commands evaluate their arguments and invoke the function inspect or xinspect with the appropriate arguments. The debugger commands will automatically load the appropriate libraries if they have not already been loaded.
The Inspector-base library exists solely to support the Text-Inspector and X-Inspector libraries. Normal users will not find it useful.
inspect [Function]
$all-libraries [Constant]
display-object-info [Function]
When the text inspector starts, it will display the object you have passed to it, along with all of the information you requested using the keyword flags. Each item will be numbered, and to inspect a sub-object you simply type the number corresponding to the desired choice (in this case, even a superclass is considered a sub-object, because it was inspected via the main object). This lets you move around the object heterarchy, but it is not very convienent. There are additional commands that are designed to allow easier use of the inspector:
With the exception of history, all commands may be abbreviated by their first letter.
The history command lists all of the previously visited objects in the current session. A sample output may look like this:
Instance of <my-class> <--- Initial object, the one given in the argument
Instance of <sequence>
Instance of <fixed-integer>
Class <fixed-integer>
Class <integer> <--- Last object seen, the one that "up" goes to
Class <rational> <--- The current object
The up command moves you "up" the history, and lets you see the previously visited object. In the above example, if you moved up twice, the history would look like this:
Instance of <my-class>
Instance of <sequence>
Instance of <fixed-integer>
Class <fixed-integer>
And you would be inspecting the class <fixed-integer>.
The print command pretty-prints the current object (using the Gwydion Print library), but does not number the sub-objects. It is useful only for displaying the objects in a different, possible more informative manner.
The store command stores the current object in the next unused debugger variable. See mindy/debug.txt for information about debugger variables.
The view command will allow you to redisplay the object that you are currently inspecting. This is mainly useful if previous commands such as history or view have moved the object off of the screen.
The help command will display a short help page listing all of the commands and a brief one line description of how they work.
This command (both words mean the same thing) will allow you to leave the inspector and continue with the execution of your program. The next time inspect is called, it will not have any memory of the past session. This means that the history will initially show only the object that you called inspector with. If inspect was invoked from the debugger, you will return to the debugger.
The X-Inspector’s graphical interface is pretty self explanatory. In addition to offering all the features of the text interface, it also offers a rudimentary class diagram viewer. (The class diagrams are non-interactive--you can click all you want on them, but they won’t do anything) The Close button will close a single window; the Quit button will close all the X-Inspector windows. When there are no longer any open X-Inspector windows, you will be returned to the Mindy debugger prompt.
The name X-Inspector is something of a misnomer, since it does not require X-Windows to work.
The X-Inspector library exports the following objects:
xinspect [Function]
$all-libraries [Constant]
Caveat: Both Inspectors differentiate between a binding (like a variable or a constant) and the object bound to that binding. If the binding is read-only, inspecting the binding is almost identical to inspecting the object it refers to. It is not exactly the same, because if the binding refers to a class, the X-Inspector will not offer you the option of a class hierarchy diagram.
Copyright 1994, 1995, 1996, 1997 Carnegie Mellon University. All rights reserved.