Using the LISP Interpreter

The LISP interpreter on the Suns is like any other program with a command line interface. A small number of commands is enough to make it work. The following should be sufficient for what we are doing:

• Starting the interpreter -- simply type "lisp".
• Quitting the interpreter -- everything you need to do from inside the interpreter is a function call; so to quit type "(quit)".
• What to do when you make an error -- LISP has extensive debugging facilities. However, we are not going to spend time learning them. If you make an error, LISP will give you some options. Chose the one that says "[ABORT] Return to Top Level." (type the number of that option which is usually but not always "0"). This will put you back where you were before you made the mistake. Then figure out what the error is by thinking about the LISP code you wrote.
• How do you edit from inside LISP -- You don't. Exit LISP and edit outside if you need to.
• How do I get the file I just edited back into LISP -- two ways:
  • Cut and paste what you have just done into a window running LISP. This requires that you be using a windowing system but is the easiest.
  • Read in an external file with LISP function(s) in it from outside using the LISP command "(load "filename")" where "filename" is the name of the file with the LISP function(s) in it. The quotes around the filename are required. This requires that you edit the LISP functions outside the interpreter.
• How do I learn more about LISP -- If you want to learn more about LISP than is in our book, you should buy a book. I can recommend a couple. If you want to know more about our particular implementation, try:
  • Do a "man lisp" for the man page.
  • If you really feel adventuresome, try the infotool. Type "info"; do the tutorial to learn how to use the infotool; then explore the material on LISP.