Using Concrete Abstractions with EdScheme for the Macintosh

This web page provides information regarding the use of the EdScheme for the Macintosh implementation of Scheme with Concrete Abstractions: An Introduction to Computer Science Using Scheme, by Max Hailperin, Barbara Kaiser, and Karl Knight.

The information here currently corresponds with the version 4.0 of EdScheme for the Macintosh; we will try to track new versions of EdScheme for the Macintosh as they come out. Note also that EdScheme for Windows is different enough that we have a separate web page for it.

Obtaining EdScheme for the Macintosh

EdScheme for the Macintosh is a Scheme development environment sold by Schemers Inc. Ordering information is available on their web site.

Settings for EdScheme for the Macintosh

For full use with the textbook, you need to increase the overall amount of memory allocated to EdScheme by the Macintosh system and the more particular amounts of memory that EdScheme itself allocates to different categories of information. The EdScheme for the Macintosh documentation explains how to make these adjustments. How much you will need to increase the amounts by depends on factors beyond our control, such as the approach you take to solving the exercises. Most of our testing was conducted with an overall memory amount of 8000, recursion depth of 2048, graphics of 500, oblist of 32, compiler of 32, and other settings left unchanged.

Libraries for use with EdScheme for the Macintosh

There are two aspects of the textbook for which a special library needs to be loaded into EdScheme for the Macintosh. One is the graphical images, introduced in the application section of chapter 1 and also used in subsequent chapters. The other is the object-oriented programming system, used in chapter 14.

Each of these libraries can be downloaded from the web below. Once you have them on your computer, you can load them into EdScheme for the Macintosh by using Load option in the Evaluate menu, or by using the load procedure. For example, you could evaluate (load "fungraph.scm") to load in the functional graphics library. You can also put these load commands into the file EdScheme Init.s, which is automatically loaded every time you start EdScheme for the Macintosh.

fungraph.scm
This is the library for graphical images. Images are not automatically displayed, unlike in the textbook (and with other Scheme implementations). Also, in addition to the features described in the textbook (most succinctly in the appendix), there are a few extensions. Descriptions of how to display images and the extensions are in a separate web page.
oops.scm
This is the object-oriented programming system for use with chapter 14.

General notes

Names defined in both Concrete Abstractions and EdScheme for the Macintosh

There are a number of names that we define in Concrete Abstractions that are already pre-defined in EdScheme for the Macintosh. The only real problem this causes is that if you perform the definition from the book, you can't expect the name to simultaneously have both the new value and the one described in the EdScheme for the Macintosh documentation.

We list below the affected names, organized into categories and listed within each category in their order of their appearance within the book:

Breaking out of interactive programs

Although EdScheme for the Macintosh allows you to interrupt evaluations by holding down the command (cloverleaf) key and pressing the period key, this won't work if the program is waiting for input from the user. This makes it rather inconvenient to get out of interactive programs, which we write from chapter 6 onward. For the game of nim in chapter 6, you will simply have to play the game to the end. The movie query system and the adventure game have explicit commands for quitting. For the micro-Scheme and mini-Scheme evaluators, you will have to enter an invalid expression (such as an undefined name) so as to provoke an error, which will get you out.

Positioning of (newline)

Starting in chapter 6, we use the newline procedure to break output into separate lines. Unfortunately, there are two different conventions in use by different Scheme systems. One is to always use newline at the start of each line of output, while the other is to always use it at the end of each line. As a result of this lack of standardization, wherever we positioned the uses of (newline) in our programs would result in output that looked odd on some systems. We've tried in the textbook to make choices that don't look too horrible on any system, with the result that the output tends to look sub-optimal on every system. In particular, there tends to be extra blank lines. If you are working consistently within EdScheme for the Macintosh (or any other one system), feel free to remove or reposition (newline) as necessary to make the output look best.

Chapter by chapter notes

Chapter 1
The procedures for manipulating graphical images need to be loaded from a library, as described above. Additionally, it is worth noting that the various basic blocks, such as rcross-bb, are neither pre-defined nor defined within the library. Instead, their definitions are in a separate file.
Chapter 9
For the application section, we have a EdScheme-specific version of the show procedure.
Chapter 11
Although you could use the SLIM simulator from the application section to work through the earlier sections of this chapter under EdScheme for the Macintosh, you'd be better off using SLIME.
Chapter 14
You will need to load a library file in to get the object-oriented programming system, as described above.
Chapter 15
EdScheme cannot be used for this chapter, since this chapter doesn't use the Scheme programming language. You will need to use a Java 1.1 system instead.
For more information, see the parent web page, or contact Max Hailperin:
Email: max@gustavus.edu
Mathematics and Computer Science Department
Gustavus Adolphus College
800 W. College Avenue
St. Peter, MN 56082
USA