September 2017 Update

Task/Jensens-Device/Phix/jensens-device.phix

@@ -0,0 +1,11 @@
+function sumr(integer lo, hi, rid)
+    atom res = 0
+    for i=lo to hi do
+        res += call_func(rid,{i})
+    end for
+    return res
+end function
+
+function reciprocal(atom i) return 1/i end function
+
+?sumr(1, 100, routine_id("reciprocal"))

Task/Jensens-Device/REXX/jensens-device.rexx

@@ -1,12 +1,15 @@
 /*REXX program demonstrates   Jensen's device   (via call subroutine, and args by name).*/
-numeric digits 90                                /*use 90 decimal digits (9 is default).*/
+parse arg d .;   if d=='' | d==","  then d=100   /*Not specified?  Then use the default.*/
+numeric digits d                                 /*use  D  decimal digits (9 is default)*/
+say 'using '    d    " decimal digits:"          /*display what's being used for digits.*/
+say
 say sum( 'i',   "1",   '100',   "1/i" )          /*invoke  SUM  (100th harmonic number).*/
 exit                                             /*stick a fork in it,  we're all done. */
 /*──────────────────────────────────────────────────────────────────────────────────────*/
-sum:  procedure;   parse arg j,start,finish,exp;              $=0
+sum: procedure;   parse arg j,start,finish,exp;              $=0
 
-      interpret  'do'    j    "="   start   'to'   finish";   $=$+"    exp    ';   end'
-             /*  ────    ═    ───   ═════   ────   ══════──────────    ═══    ───────── */
-             /*   lit   var   lit    var     lit     var   literal     var     literal  */
+     interpret   'do'    j    "="   start   'to'   finish";   $=$+"    exp    ';   end'
+            /*   ────    ═    ───   ═════   ────   ══════──────────    ═══    ───────── */
+            /*    lit   var   lit    var     lit     var   literal     var     literal  */
 
-      return $
+     return $

Task/Jensens-Device/Simula/jensens-device.simula

@@ -0,0 +1,23 @@
+comment Jensen's Device;
+begin
+   integer i;
+   real procedure sum (i, lo, hi, term);
+      name i, term;
+      value lo, hi;
+      integer i, lo, hi;
+      real term;
+      comment term is passed by-name, and so is i;
+   begin
+      integer j;
+      real temp;
+      temp := 0;
+      for j := lo step 1 until hi do
+      begin
+         i := j;
+         temp := temp + term
+      end;
+      sum := temp
+   end;
+   comment note the correspondence between the mathematical notation and the call to sum;
+   outreal (sum (i, 1, 100, 1/i), 7, 14)
+end

Task/Jensens-Device/Zkl/jensens-device-1.zkl

@@ -0,0 +1,6 @@
+fcn sum(ri, lo,hi, term){
+   temp:=0.0; ri.set(lo);
+   do{ temp+=term(ri); } while(ri.inc()<hi); // inc return previous value
+   return(temp);
+}
+sum(Ref(0), 1,100, fcn(ri){ 1.0/ri.value }).println();

Task/Jensens-Device/Zkl/jensens-device-2.zkl

@@ -0,0 +1,7 @@
+fcn sum2(ri, lo,hi, term){
+   temp:=0.0; ri.set(lo);
+   do{ temp=term + temp; } while(ri.inc()<hi); // inc return previous value
+   return(temp);
+}
+ri:=Ref(0);
+sum2(ri, 1,100, 'wrap(){ 1.0/ri.value }).println();

Task/Jensens-Device/Zkl/jensens-device-3.zkl

@@ -0,0 +1,2 @@
+fcn sum3(lo,hi, term){ [lo..hi].reduce('wrap(sum,i){ sum + term(i) },0.0) }
+sum3(1,100, fcn(i){ 1.0/i }).println();