Another update from ingydotnet^djgoku

Task/Arithmetic-Integer/REXX/arithmetic-integer.rexx

@@ -1,26 +1,24 @@
-/*REXX pgm gets 2 integers from the C.L. or via prompt, shows some opers*/
-numeric digits 20                      /*all numbers are rounded at ··· */
-                                       /*··· the 20th significant digit.*/
-parse arg x y .                        /*maybe the integers are on C.L.?*/
-if y==''  then do                      /*nope, then prompt user for 'em.*/
-               say "─────Enter two integer values  (separated by blanks):"
-               parse pull x y .
-               end
-     do 2                              /*show  A with B, then  B with A.*/
-     say                               /*show blank line for eyeballing.*/
+/*REXX pgm gets 2 integers from the C,L. or via prompt; shows some operations.*/
+numeric digits 20                      /*#s are round at 20th significant dig.*/
+parse arg x y .                        /*maybe the integers are on the  C.L.  */
 
-     call show 'addition'      , "+",  x+y
-     call show 'subtraction'   , "-",  x-y
-     call show 'multiplication', "*",  x*y
-     call show 'int  division' , "%",  x%y,   '   [rounds down]'
-     call show 'real division' , "/",  x/y
-     call show 'div remainder' , "//", x//y, '    [sign from 1st operand]'
-     call show 'power'         , "**", x**y
+  do while \datatype(x,'W') | \datatype(y,'W')    /*both X and Y must be ints.*/
+  say "─────Enter two integer values  (separated by blanks):"
+  parse pull x y .                     /*accept two items from command line.  */
+  end   /*while ··· */
+                                       /* [↓]  perform this  DO  loop twice.  */
+     do j=1  for 2                     /*show  A  oper  B,   then  B  oper  A.*/
+     call show 'addition'          ,  "+",   x+y
+     call show 'subtraction'       ,  "-",   x-y
+     call show 'multiplication'    ,  "*",   x*y
+     call show 'int  division'     ,  "%",   x%y,  '    [rounds down]'
+     call show 'real division'     ,  "/",   x/y
+     call show 'division remainder',  "//",  x//y, '    [sign from 1st operand]'
+     call show 'power'             ,  "**",  x**y
 
-     parse value  x y  with  y x       /*swap the two values & do again.*/
-     end   /*2*/
-exit                                   /*stick a fork in it, we're done.*/
-/*──────────────────────────────────SHOW subroutine─────────────────────*/
-show: parse arg what,oper,value,comment
-say right(what,25)' '   x  center(oper,4)  y    ' ───► '    value  comment
-return
+     parse value  x y  with  y x       /*swap the two values and perform again*/
+     if j==1  then say copies('═', 79) /*display a fence after the 1st round. */
+     end   /*j*/
+exit                                   /*stick a fork in it,  we're all done. */
+/*────────────────────────────────────────────────────────────────────────────*/
+show: parse arg c,o,#,?; say right(c,25)' ' x center(o,4) y ' ───► ' # ?; return