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.
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.