set editor command;
This sets the command line that gets invoked when using edit.
The argument command must be a string. When you run
edit, it will prepend the string to the filename specified (with a
space) and run it as a shell command. The command can therefore
include flags. For example, ``set editor "xterm -e vi";'' will
set up the editor so that it will invoke vi within a new xterm.
edit [filename];
This starts the editor (which must have previously been set with
set editor) on the NESL file filename. If no filename is
specified, it defaults to the last file loaded. If the filename ends
with the suffix ``.nesl'', the suffix can be omitted. When you
exit from the editor, you will be asked if you want to load the file
you just edited.