Browse Prior Art Database

Unsaved Changes Tool for Object-Oriented Programming Environment

IP.com Disclosure Number: IPCOM000120602D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 92K

Publishing Venue

IBM

Related People

Cavendish, C: AUTHOR [+2]

Abstract

When creating new applications in an object-oriented environment, such as Digitalk's Smalltalk/V (and its family of programs V/286, V/PM and V/Windows), many programming bugs cause system errors which crash the execution image. While this problem extends across many programming development environments, in most cases the only result of the crash is having to find and fix the bug. In Smalltalk/V, however, if the environment crashes, all programming changes made since the last saved image are lost except for a script kept in a change log. Currently, recovery requires a tedious search through the log of all the changes made to the system since its installation to find the appropriate changes to file in. This article describes a tool which was built to allow a Smalltalk programmer to quickly and easily recover from an image crash.

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This is the abbreviated version, containing approximately 52% of the total text.

Unsaved Changes Tool for Object-Oriented Programming Environment

      When creating new applications in an object-oriented
environment, such as Digitalk's Smalltalk/V (and its family of
programs V/286, V/PM and V/Windows), many programming bugs cause
system errors which crash the execution image. While this problem
extends across many programming development environments, in most
cases the only result of the crash is having to find and fix the bug.
In Smalltalk/V, however, if the environment crashes, all programming
changes made since the last saved image are lost except for a script
kept in a change log.  Currently, recovery requires a tedious search
through the log of all the changes made to the system since its
installation to find the appropriate changes to file in. This article
describes a tool which was built to allow a Smalltalk programmer to
quickly and easily recover from an image crash.

      Smalltalk/V uses a file called the change log file to hold the
source code of the methods that the user has created or modified in
the course of his work.  This file is considered to be part of the
environment image, specifically containing everything the user has
typed in.  These changes include creation or modification of a
method, deletion of a method, creation or modification of a class and
deletion of a class as well as a history of all the Smalltalk code
that the user has explicitly executed in testing his application.

      As the user modifies the environment, the change log file and
the class hierarchy browser are dynamically updated with the changes
that the user has made.  Each change is appended to the end of the
change log file.  On a system crash, the user must restart the
environment, edit the change.log file and manually extract all the
changes made since the last time the image was saved.  This is both
tedious and time consuming, and often a lot of redundant data, such
as a method the user has modified several times until he was
satisfied with the changes, is included.  The change log file gets
very large as development progresses and is easily several megabytes
in size.

      The solution provided here is an addition to the
object-oriented envi...