Data commit

Task/Deepcopy/Icon/deepcopy-1.icon

@@ -0,0 +1,24 @@
+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

Task/Deepcopy/Icon/deepcopy-2.icon

@@ -0,0 +1,54 @@
+link printf,ximage
+
+procedure main()
+
+   knot    := makeknot()     # create a structure with loops
+   knota   := knot           # copy by assignment (reference)
+   knotc   := copy(knot)     # built-in copy (shallow)
+   knotdc  := deepcopy(knot) # deep copy
+
+
+   showdeep("knota  (assignment) vs. knot",knota,knot)
+   showdeep("knotc  (copy)  vs. knot",knotc,knot)
+   showdeep("knotdc (deepcopy)  vs. knot",knotdc,knot)
+
+   xdump("knot   (original)",knot)
+   xdump("knota  (assignment)",knota)
+   xdump("knotc  (copy)",knotc)
+   xdump("knotdc (deepcopy)",knotdc)
+end
+
+record rec1(a,b,c)      # record for example
+
+class Class1(a1,a2)     # class - looks like a record under the covers
+   method one()
+      self.a1 := 1
+      return
+   end
+initially
+   self.a1 := 0
+end
+
+
+procedure makeknot()    #: return a homogeneous structure with loops
+   L := [9,8,7]
+   T := table()
+   T["a"] := 1
+   R := rec1(T)
+   S := set(R)
+   C := Class1()
+   C.one()
+   T["knot"] := [L,R,S,C]
+   put(L,R,S,T,C)
+   return L
+end
+
+procedure showdeep(tag,XC,X)    #: demo to show (non-)equivalence of list elements
+   printf("Analysis of copy depth for %s:\n",tag)
+   showequiv(XC,X)
+   every showequiv(XC[i := 1 to *X],X[i])
+end
+
+procedure showequiv(x,y)       #: show (non-)equivalence of two values
+   return printf("   %i %s %i\n",x,if x === y then "===" else "~===",y)
+end