Keystrokes, Mouse menus and Gestures

The handling of keyboard and mouse clicks and gestures is different and varied within the Medley environment. This chart shows common keystrokes. On macOS the Option key is equivalent to Alt. See Table of Keystrokes for more data.

We’d like to improve keyboard handling but haven’t yet found a path.

At an “exec” (i.e., the REPL)

character	action
Backspace	delete the previous character
Ctrl-H	(same as backspace)
Enter	if terminates a valid expression evaluate, otherwise newline
Ctrl-M	(same as Enter)
Ctrl-Alt-J	move down
Ctrl-Alt-L	move to start of line (some OSes capture this for system functions, e.g. screen lock on Linux)
Ctrl-Alt-Y	invoke an old-style executive (REPL), but uses the package and readtable of its caller

Interrupt characters

These are enabled per-process. Medley maintains, for each process, a “termtable” which enables different kinds of interrupts.

Usually, the user wants interrupts to occur in the TTY process, which is the one currently receiving keyboard input. However, sometimes the user wants to interrupt the mouse process, if it is currently busy executing a menu command or waiting for the user to specify a region on the screen. Most of the interrupt characters below take place in the mouse process if it is busy, otherwise the TTY process.

character	action
Ctrl-B	stop the process and enter a break window
Ctrl-D	reset the process, unwind the stack to the top level
Ctrl-E	unwind the stack as if an error occured without break
Ctrl-G	interrupt a non TTY process and open the debugger
Ctrl-P	interrupt printing and reset the PRINTLEVEL