Getting Started With DrScheme

DrScheme is a tool that helps you write, debug, and run your Scheme programs. It is available for free for all major platforms, including Windows, Macintosh, and Unix. If you want a copy for home, use Firefox to go from the course home page to the Concrete Abstractions supporting materials page, and then to the page on using DrScheme.

To start DrScheme on one of our Linux machines, use the same general technique as for starting up Firefox: Starting from the main menu, go to the MCS submenu and then select DrScheme.

The first time you start DrScheme you will be greeted with a window warning you that you haven't chosen which Scheme language to use:

As instructed, select "Choose Language..." under the pull-down menu "Language". This will bring us to a panel asking us to choose a version of the Scheme programming language to use in DrScheme:

Click the triangle next to "PLT" (or double-click PLT itself) so as to expose more options listed under it and click the "Textual" option under "PLT" to select it.

Lastly, click ok. In the main DrScheme window, click on the Run button to install the chosen language.

You will type your programs into the upper half of the DrScheme window (called the definition window) and you will interact with DrScheme in the lower half (called the interaction window).

Now you are ready to start doing real work. In the interaction window, type the following Scheme expression: (and press enter).

(+ 5 5)

Scheme evaluates the expression and prints its value:

Next, try typing the definition of a simple Scheme procedure into the definition window:

(define double
  (lambda (x)
    (+ x x)))

Then click the Run button to load your definition into the interaction window. You can then run this procedure by typing the following expressions in the interaction window:

  (double 5)
  (double 10)

Most of the time you can ignore the menus and use the following buttons to interact with DrScheme:

DrScheme can inspect your code before you execute it to check for certain kinds of errors. After it checks your code, DrScheme displays it in a color-coded form that some find easier to read:

In a black-and-white printout this isn't likely to look very different. You can also use bold, italic, etc. instead of color. Select Preferences from the Edit menu to change the appearance of keywords, variables, constants, and built-in procedures.

After checking syntax, try positioning the mouse over a variable: DrScheme will draw an arrow to indicate where the variable was bound (or where the binding occurrence of a variable is used).
Loads your definitions into the interaction window. This clears the interaction window so you can no longer see tests you did with the previous version of your definitions.

For more information, visit the DrScheme documentation page:

http://www.drscheme.org/docs.html

This document was customized for Gustavus by Max Hailperin from a version created at Indiana University by Mark Leone, now of Zoesis, Inc. Permission to reproduce and modify was granted by Suzanne Menzel of Indiana University.