Using Concrete Abstractions with Other Schemes

This web page provides information regarding the use of Scheme implementations other than the ones we specifically support with Concrete Abstractions: An Introduction to Computer Science Using Scheme, by Max Hailperin, Barbara Kaiser, and Karl Knight.

Naturally we can't address all problems that might arise with an arbitrary Scheme implementation. Thus, we would suggest that students working on their own would be best off using one of the Scheme implementations we specifically support. However, course instructors who are familiar with a particular Scheme implementation might prefer to use that implementation. To help those instructors, we provide here some sample code that can serve as a starting point for developing a compatability library. You should also read the Appendix of the book, which points out those areas where compatability problems are likely to arise.

Compatability library

The following files implement the non-standard Scheme procedures assumed by the book in terms of R⁴RS standard features.

error.scm This defines the error reporting procedure, error, which is assumed in the book (from chapter 6 onward) and also by the following two files. Check whether you really need this; many Scheme systems do provide error. Even if you do need this, you may be able to improve on the way it aborts execution after the error is reported.
random.scm This defines the pseduo-random number generation procedure, random, which is used in chapters 6, 11, and 14.
fungraph.scm This defines the graphics procedures used in chapters 1 through 4. Rather than actually displaying the images, it provides a save-image-as-epsf procedure which can be used to save an image out into an Encapsulated PostScript file. You would then need to use system-specific means to view or print that file.

General notes

Names defined in both Concrete Abstractions and the Scheme implementation

R⁴RS names noted as such in the text
- length
- list-ref
- list-tail
- map
- reverse
R⁴RS names not noted as such in the text
- gcd
Non-R⁴RS names: You should beware that some Scheme implementations may define names that aren't in the R⁴RS and that are used in the text.

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 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 11: Although you could use the SLIM simulator from the application section to work through the earlier sections of this chapter under Scheme, you'd be better off using SLIME.
Chapter 14: You will need to load a library file to get the object-oriented programming system. A good starting point would be our system-independent version.
Chapter 15: Scheme 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: