introduce dec function

help.inc

@@ -100,7 +100,7 @@ clip.size pop 800 eq {
   {
     bo.pos 0 eq { exit } if
     bo.buf bo.pos 1 sub get ' ' le  { exit } if
-    /bo.pos bo.pos 1 sub def
+    /bo.pos dec
   } loop
 
   /bo.buf bo.buf bo.pos add def
@@ -388,7 +388,7 @@ clip.size pop 800 eq {
 %
 /help.prevlink {
   help.hist.index 0 gt {
-    /help.hist.index help.hist.index 1 sub def
+    /help.hist.index dec
     help.hist.page help.hist.index get
     help.hist.startrow help.hist.index get
     help.hist.selectedlink help.hist.index get
@@ -534,7 +534,7 @@ clip.size pop 800 eq {
   % scroll up
 
   help.startrow 0 gt {
-    /help.startrow help.startrow 1 sub def
+    /help.startrow dec
     help.updatepage
   } if
 } def

main.inc

@@ -172,9 +172,9 @@
     menu.entry 0 gt {
       menu.entry false MenuSelect
       menu.entry menu.shift eq {
-        /menu.shift menu.shift 1 sub def redrawmenu
+        /menu.shift dec redrawmenu
       } if
-      /menu.entry menu.entry 1 sub def
+      /menu.entry dec
       menu.entry true MenuSelect
     } if
     pop 0

system.inc

@@ -294,6 +294,16 @@ def
 } def
 
 
+% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+% Decrement variable.
+%
+% ( dict_ref ) ==> ( )
+%
+/dec {
+  dup exec 1 sub def
+} def
+
+
 % - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 % Copy src to dst.
 %

window.inc

@@ -223,7 +223,7 @@
 %
 /window.pop {
   window.list.index 0 eq { .undef return } if
-  /window.list.index window.list.index 1 sub def
+  /window.list.index dec
   window.list window.list.index get
   window.list window.list.index .undef put
   /window.current