Using DrScheme Jr

DrScheme Jr is an alternative to DrScheme that uses less memory and only supports a textual interface. To invoke DrScheme Jr on:

Windows and the Macintosh, drag your program onto the DrScheme Jr icon, and under

Unix, type drscheme-jr filename.ss, where filename.ss is the name of your file.

To test a new program, use the restart function. Evaluating (restart) in DrScheme Jr clears out the repl and re-evaluates the program. The restart function also accepts an optional argument. If specified, the argument names a file containing a new program to be evaluated, after the repl is cleared out.

The language level for DrScheme Jr is set via command-line flags. To set DrScheme Jr's language level to Beginner:

• Under Windows, run "DrScheme Jr" -l Beginner -save in a command shell in the plt directory.
• Under MacOS, double-click on DrScheme Jr. A dialog appears with a text box that lets you enter command line arguments. Type -l Beginner -save into the text box and click OK.
• Under Unix, run plt/bin/drscheme-jr -l Beginner -save in a shell.

The -save flag (note that there are two dashes) saves the language level selection to a special file. (Run DrScheme Jr with the -help flag to determine the name of this file.) When DrScheme Jr is restarted, it reads this file to obtain the previously selected language level. Thus, after setting the language level once, DrScheme Jr will automatically use that language level when it is restarted. (Under MacOS, to use a previously selected language level, click OK in the initial dialog without typing into the text box.)