2016 Update

Task/Generic-swap/00DESCRIPTION

@@ -1,4 +1,6 @@
-The task is to write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
+;Task:
+Write a generic swap function or operator which exchanges the values of two variables (or, more generally, any two storage places that can be assigned), regardless of their types.
+
 If your solution language is statically typed please describe the way your language provides genericity.
 
 If variables are typed in the given language, it is permissible that the two variables be constrained to having a mutually compatible type, such that each is permitted to hold the value previously stored in the other without a type violation.
@@ -13,3 +15,4 @@ Functional languages, whether static or dynamic, do not necessarily allow a dest
 Some static languages have difficulties with generic programming due to a lack of support for ([[Parametric Polymorphism]]).
 
 Do your best!
+<br><br>

Task/Generic-swap/360-Assembly/generic-swap.360

@@ -0,0 +1,20 @@
+SWAP     CSECT ,                   control section start
+         BAKR  14,0                stack caller's registers
+         LR    12,15               entry point address to reg.12
+         USING SWAP,12             use as base
+         MVC   A,=C'5678____'      init field A
+         MVC   B,=C'____1234'      init field B
+         LA    2,L                 address of length field in reg.2
+         WTO   TEXT=(2)            Write To Operator, results in:
+*                                  +5678________1234
+         XC    A,B                 XOR A,B
+         XC    B,A                 XOR B,A
+         XC    A,B                 XOR A,B. A holds B, B holds A
+         WTO   TEXT=(2)            Write To Operator, results in:
+*                                  +____12345678____
+         PR    ,                   return to caller
+         LTORG ,                   literals displacement
+L        DC    H'16'               halfword containg decimal 16
+A        DS    CL8                 field A, 8 bytes
+B        DS    CL8                 field B, 8 bytes
+         END   SWAP                program end

Task/Generic-swap/Ada/generic-swap-1.ada

@@ -1,9 +1,9 @@
 generic
    type Swap_Type is private; -- Generic parameter
-procedure Generic_Swap(Left : in out Swap_Type; Right : in out Swap_Type);
+procedure Generic_Swap (Left, Right : in out Swap_Type);
 
-procedure Generic_Swap(Left : in out Swap_Type; Right : in out Swap_Type) is
-   Temp : Swap_Type := Left;
+procedure Generic_Swap (Left, Right : in out Swap_Type) is
+   Temp : constant Swap_Type := Left;
 begin
    Left := Right;
    Right := Temp;

Task/Generic-swap/Ada/generic-swap-2.ada

@@ -1,7 +1,7 @@
 with Generic_Swap;
 ...
 type T is ...
-package T_Swap is new Generic_Swap(Swap_Type => T);
-A,B:T;
+procedure T_Swap is new Generic_Swap (Swap_Type => T);
+A, B : T;
 ...
-T_Swap(A,B);
+T_Swap (A, B);

Task/Generic-swap/PL-I/generic-swap-1.pli

@@ -3,9 +3,3 @@
    return ( 't=' || a || ';' || a || '=' || b || ';' || b '=t;' );
 %end swap;
 %activate swap;
-
-The statement:-
-   swap (p, q);
-
-is replaced, at compile time, by the three statements:
-   t = p; p = q; q = t;

Task/Generic-swap/PL-I/generic-swap-5.pli

@@ -0,0 +1,4 @@
+%Swap:Procedure(a,b);
+   declare (a,b) character; /*These are proper strings of arbitrary length, pre-processor only.*/
+   return ('Begin; declare t like '|| a ||'; t='|| a ||';'|| a ||'='|| b ||';'|| b ||'=t; End;');
+%End Swap;

Task/Generic-swap/PL-I/generic-swap-6.pli

@@ -0,0 +1,6 @@
+Begin;
+ declare t like this;
+  t = this;
+  this = that;
+  that = t;
+End;

Task/Generic-swap/TXR/generic-swap-1.txr

@@ -0,0 +1,5 @@
+(defmacro swp (left right)
+  (with-gensyms (tmp)
+    ^(let ((,tmp ,left))
+       (set ,left ,right
+            ,right ,tmp))))

Task/Generic-swap/TXR/generic-swap-2.txr

@@ -0,0 +1,7 @@
+(defmacro swp (left right)
+  (with-gensyms (tmp lpl rpl)
+    ^(placelet ((,lpl ,left)
+                (,rpl ,right))
+       (let ((,tmp ,lpl))
+         (set ,lpl ,rpl
+              ,rpl ,tmp)))))

Task/Generic-swap/TXR/generic-swap-3.txr

@@ -0,0 +1,7 @@
+(defmacro swp (left right :env env)
+  (with-gensyms (tmp)
+    (with-update-expander (l-getter l-setter) left env
+      (with-update-expander (r-getter r-setter) right env
+        ^(let ((,tmp (,l-getter)))
+           (,l-setter (,r-getter))
+           (,r-setter ,tmp))))))