When editing or viewing long procedure definitions it is easy to forget which procedure you are looking at when the procedure statement itself is off the top of the screen. REDUCE mode can show in the mode line the name of the procedure (if any) that point is in. This facility is turned on and off by the command M-x reduce-show-proc-mode or via the REDUCE mode menu; it is off by default. (It is analogous to the standard Emacs “Which Function” mode, but it is implemented differently and largely independently.)
Toggle REDUCE Show Proc mode. With a prefix argument, turn REDUCE Show
Proc mode on if and only if the argument is positive. When REDUCE Show
Proc mode is enabled, display the current procedure name in the mode
reduce-show-proc-delay seconds of Emacs idle time.