*com-documentation-alist* et al.

[Randy Parker <PARKER@OZ>]

In Symbolics 3600 ZWEI in Release 6.0, IP-TCP 29.0, AISite 9.4,
microcode TMC5-MIC 319, FEP 18, on Lisp Machine Apiary-4:

IWBNI this set of keys was consulted in COM-DOCUMENTATION,
instead of it being "hardwired", so that this documentation facility
could be extended easily by just pushing a new pair.

;;;; From sys:zwei;doc.lisp

(DEFVAR *COM-DOCUMENTATION-ALIST*
	'((#/C . COM-SELF-DOCUMENT)
	  (#/L . COM-LAST-COMMANDS)
	  (#/D . COM-DESCRIBE-COMMAND)
	  (#/A . COM-APROPOS)
	  (#/U . COM-UNDO)
	  (#/V . COM-VARIABLE-APROPOS)
	  (#/W . COM-WHERE-IS)))

(DEFCOM COM-DOCUMENTATION
	"Displays information about commands, performs other help functions.
It prompts in the minibuffer for a help option, which is a single character
for requesting more specific help.
 A  Displays all the commands whose names contain a certain substring.  Type the string.
 C  Displays documentation for a command.  Press the command key after the C.
 D  Displays documentation for an extended command.  Type the command name.
 L  Displays the last 60 characters you typed.
 U  Offers to undo the last /"major/" operation (such as fill, sort).
 V  Displays all the Zmacs variables whose names contain a certain substring.  Type it.
 W  Finds out whether an extended command is bound to a key.  Type the command name.
Using SPACE repeats the most recent HELP command.  " ()
  (DO-NAMED TOP
      ((CHAR 0)
       (*IN-COM-DOC-P* T)
       (*REPEAT-DOC-P* NIL))
      (NIL)
    (TYPEIN-LINE " Help.  Type one of A,C,D~:[~;,L~]~:[~;,U~],V,W,Space,Help,Abort: "  ;;<------*****
		 (MEMQ ':PLAYBACK (FUNCALL STANDARD-INPUT ':WHICH-OPERATIONS))
		 (BOUNDP '*UNDO-START-BP*))
    (TYPEIN-LINE-ACTIVATE
      (SETQ CHAR (DO ((CHAR (CHAR-UPCASE (EDITOR-INPUT))
			    (CHAR-UPCASE (EDITOR-INPUT))))
		     ((MEMQ CHAR '(#/A #/C #/D #/L #/U #/V #/W #\SP #/? #\HELP)) CHAR) ;; <<------******
		   (COND ((= CHAR #\c-G)
			  (FUNCALL *TYPEIN-WINDOW* ':CLEAR-WINDOW)
			  (BARF))
			 ((OR (= CHAR #\ABORT)
			      (= CHAR #\RUBOUT))
			  (FUNCALL *TYPEIN-WINDOW* ':CLEAR-WINDOW)
			  (RETURN-FROM TOP DIS-NONE)))
		   (BEEP))))
    (FUNCALL *TYPEIN-WINDOW* ':MAKE-COMPLETE)
    (COND ((= CHAR #\SP)
	   (SETQ *REPEAT-DOC-P* T)
	   (SETQ CHAR *COM-DOC-LAST-CHAR*))
	  (T (SETQ *COM-DOC-LAST-CHAR* CHAR)))
    (IF (MEMQ CHAR '(#\HELP #/?))
	(FORMAT T "COM-DOCUMENTATION:~%~A~&"
		(GET 'COM-DOCUMENTATION 'DOCUMENTATION))
	(LET ((FUNCTION (CDR (ASSQ CHAR *COM-DOCUMENTATION-ALIST*))))
	  (WHEN FUNCTION
	    ;; This kludge fudges the minibuffer history so that if this command uses
	    ;; the minibuffer and is repeated, we will go straight to it instead of
	    ;; coming back here and asking again for a character to dispatch on.
	    (SETQ *CURRENT-COMMAND* FUNCTION)
	    (RETURN (FUNCALL FUNCTION)))))))