Is copy and paste available?

In Medley, there are three main editors used commonly:

  • TEdit (full WYSIWYG styled text editor)
  • SEdit (structure editor for Lisp code, package aware)
  • TTYIN (Type-in using keyboard)

The original method for copy/paste is different from most modern systems:

  • click with mouse the destination
  • hold down the shift key, and, while holding, select the source (using left mouse button to select a point, right button or repeated left button to extend the selection)
  • let up the shift key. The system will copy from the selected content and paste it in the destination.

To do a cut/paste operation, hold down the control key as well as the shift key.

Modern Medley (in the CLIPBOARD software) adds an interface with the host OS’s Clipboard. Typing meta-C does copy to clipboard, and meta-V will paste from the clipboard into the destination. The ‘meta’ key is the one labeled ‘cmd’ on a Macintosh, and the left side ‘Alt’ key on most windows keyboards.

How to ask for help about a specific function?

There is a graphical browser of the Interlisp Reference Manual – right click any area of the screen not in a window (i.e., the background) and select DInfo.

The MAN command can be used in an EXEC:


In addition, typein of a list structure followed by a question mark followed by an ’enter’ will look up (using DInfo) the symbol entered in the enclosing list:


Modern Medley extends this to look up Common Lisp functions in the Common Lisp HyperSpec.

Further, typein of a expression form followed by a question mark and equals sign followed by an ’enter’ will look up the closest function name (for any defined function) entered in the form and display that function’s invocation form:




Interlisp EXEC commands are case and package insensitive, although the rest of the input line depends on the context.

When to pop up a debugger or just report an error and unwind?

Interlisp uses a heuristic to decide when to simply print an error message and when to open a “break” window for the error; the decision is based on compute-time-since-last-user-input and stack depth. We’ve adjusted these parameters but modern machines are 1000 times faster, and the clock resolution is too coarse.

The retry command is handy in this situation.

For example typing (+ 1 Z) may only show the error message:
Z is an unbound variable.
without a break window opening. If you


then a debugger window will pop up. Let’s give Z a value while in the debugger:

(SETQ Z 9)

now type OK and enter (or middle click in the debugger then choose Ok). It will continue the execution as if the fault never happened. It will return the value 10.