KEYFUNCTION function

Evaluates an integer expression (such as 301) and returns a character string that is the function of the key associated with that integer expression (such as GO).


KEYFUNCTION ( `expression` )

This procedure displays a menu and highlights different selections, depending on which key you press. On the first iteration of the REPEAT block, the COLOR statement tells the AVM to color msg[ix] with the same color used to display messages. Because the initial value of ix is 1, msg[ix] is the first menu selection. Therefore, the first menu selection is colored MESSAGES.

r-keyfn.p
DEFINE VARIABLE msg AS CHARACTER NO-UNDO EXTENT 3. DEFINE VARIABLE ix AS INTEGER NO-UNDO INITIAL 1. DEFINE VARIABLE newi AS INTEGER NO-UNDO INITIAL 1. DEFINE VARIABLE func AS CHARACTER NO-UNDO. DISPLAY " Please choose " SKIP(1) " 1 Run order entry " @ msg[1] ATTR-SPACE SKIP " 2 Run receivables " @ msg[2] ATTR-SPACE SKIP " 3 Exit " @ msg[3] ATTR-SPACE SKIP WITH CENTERED FRAME menu NO-LABELS. REPEAT: COLOR DISPLAY MESSAGES msg[ix] WITH FRAME menu. READKEY. func = KEYFUNCTION(LASTKEY). IF func = "CURSOR-DOWN" AND ix < 3 THEN newi = ix + 1. ELSE IF func = "CURSOR-UP" AND ix > 1 THEN newi = ix - 1. ELSE IF func = "GO" OR func = "RETURN" THEN LEAVE. IF ix <> newi THEN COLOR DISPLAY NORMAL msg[ix] WITH FRAME menu. ix = newi. END.

r-keyfn.p

DEFINE VARIABLE msg  AS CHARACTER NO-UNDO EXTENT 3. 
DEFINE VARIABLE ix   AS INTEGER   NO-UNDO INITIAL 1. 
DEFINE VARIABLE newi AS INTEGER   NO-UNDO INITIAL 1. 
DEFINE VARIABLE func AS CHARACTER NO-UNDO. 
DISPLAY  
  "     Please choose     " SKIP(1) 
  " 1  Run order entry    " @ msg[1] ATTR-SPACE SKIP 
  " 2  Run receivables    " @ msg[2] ATTR-SPACE SKIP 
  " 3  Exit               " @ msg[3] ATTR-SPACE SKIP 
  WITH CENTERED FRAME menu NO-LABELS. 
REPEAT: 
  COLOR DISPLAY MESSAGES msg[ix] WITH FRAME menu. 
  READKEY. 
  func = KEYFUNCTION(LASTKEY). 
  IF func = "CURSOR-DOWN" AND ix < 3 THEN  
    newi = ix + 1. 
  ELSE IF func = "CURSOR-UP" AND ix > 1 THEN 
    newi = ix - 1. 
  ELSE IF func = "GO" OR func = "RETURN" THEN LEAVE. 
  IF ix <> newi THEN  
    COLOR DISPLAY NORMAL msg[ix] WITH FRAME menu. 
  ix = newi. 
END.

See the example in the KEYCODE function reference entry for details on what happens if you press keylabel component.

The value returned by the KEYFUNCTION function is affected by any ON statements you use to redefine the value of the key represented by expression.

If the key represented by expression has no function currently assigned to it or if it has the function of BELL, KEYFUNCTION returns a null value.

KEYFUNCTION(-2) is equal to ENDKEY.