Initial data commit

Task/Polymorphic-copy/Icon/polymorphic-copy.icon

@@ -0,0 +1,36 @@
+class T()
+    method a(); write("This is T's a"); end
+end
+
+class S: T()
+    method a(); write("This is S's a"); end
+end
+
+procedure main()
+    write("S:",deepcopy(S()).a())
+end
+
+procedure deepcopy(A, cache)  #: return a deepcopy of A
+    local k
+
+    /cache := table()        # used to handle multireferenced objects
+    if \cache[A] then return cache[A]
+
+    case type(A) of {
+        "table"|"list": {
+            cache[A] := copy(A)
+            every cache[A][k := key(A)] := deepcopy(A[k], cache)
+            }
+        "set": {
+            cache[A] := set()
+            every insert(cache[A], deepcopy(!A, cache))
+            }
+        default: {           # records and objects (encoded as records)
+            cache[A] := copy(A)
+            if match("record ",image(A)) then {
+                every cache[A][k := key(A)] := deepcopy(A[k], cache)
+                }
+            }
+        }
+    return .cache[A]
+end