Data update

Task/Polymorphic-copy/Ada/polymorphic-copy.adb

@@ -0,0 +1,53 @@
+with Ada.Text_IO;  use Ada.Text_IO;
+
+procedure Test_Polymorphic_Copy is
+   package Base is
+      type T is tagged null record;
+      type T_ptr is access all T'Class;
+      function Name (X : T) return String;
+   end Base;
+   use Base;
+
+   package body Base is
+      function Name (X : T) return String is
+      begin
+         return "T";
+      end Name;
+   end Base;
+
+      -- The procedure knows nothing about S
+   procedure Copier (X : T'Class) is
+      Duplicate : T'Class := X;  -- A copy of X
+   begin
+      Put_Line ("Copied " & Duplicate.Name); -- Check the copy
+   end Copier;
+
+      -- The function knows nothing about S and creates a copy on the heap
+   function Clone (X : T'Class) return T_ptr is
+   begin
+      return new T'Class'(X);
+   end Clone;
+
+   package Derived is
+      type S is new T with null record;
+      overriding function Name (X : S) return String;
+   end Derived;
+   use Derived;
+
+   package body Derived is
+      function Name (X : S) return String is
+      begin
+         return "S";
+      end Name;
+   end Derived;
+
+   Object_1 : T;
+   Object_2 : S;
+   Object_3 : T_ptr := Clone(Object_1);
+   Object_4 : T_ptr := Clone(Object_2);
+begin
+   Copier (Object_1);
+   Copier (Object_2);
+   Put_Line ("Cloned " & Object_3.all.Name);
+   Put_Line ("Cloned " & Object_4.all.Name);
+end Test_Polymorphic_Copy;

Task/Polymorphic-copy/V-(Vlang)/polymorphic-copy.v

@@ -0,0 +1,70 @@
+interface Iden {
+    identify() string
+}
+
+struct Tina {
+    value f64
+}
+
+// structs can be embedded
+
+struct Sara {
+    tina Tina
+    koan string
+}
+
+struct Ryan {
+    tina Tina
+    ch chan int
+}
+
+// methods assigned to structs
+
+fn (x Tina) identify() string {
+    return "I'm a Tina!"
+}
+
+fn (x Sara) identify() string {
+    return "I'm a Sara!"
+}
+
+fn (x Ryan) identify() string {
+    return x.tina.identify()
+}
+
+fn main() {
+    // initialization of three variables with different types
+    tina1 := Tina{5}
+    sara1 := Sara{Tina{6}, "one"}
+    ryan1 := Ryan{Tina{7}, chan int{}}
+
+    // variables declared with the same interface type
+    mut i1, mut i2, mut i3 := []Iden{}, []Iden{}, []Iden{}
+    println("Initial (zero) values of interface variables:")
+    println("i1: ${i1}")
+    println("i2: ${i2}")
+    println("i3: ${i3}")
+
+    // i1, i2, and i3 have the static type of the interface, along with other different types.
+    i1 << [tina1]; i2 << [sara1]; i3 << [ryan1] // semicolons can be used as optional separators in Vlang
+    println("\nPolymorphic:")
+    println("i1: ${i1} / ${i1[0].identify()} / ${typeof(i1[0]).name}\n")
+    println("i2: ${i2} / ${i2[0].identify()} / ${typeof(i2[0]).name}\n")
+    println("i3: ${i3} / ${i3[0].identify()} / ${typeof(i3[0]).name}\n")
+
+     // copy: declare and assign in one step using "short declaration"
+    i1c, i2c, i3c := i1, i2, i3
+
+    // modify first set of polymorphic variables.
+    i1, i2, i3 = [Sara{Tina{3}, "dog"}], [Ryan{Tina{1}, chan int{}}], [Tina{2}]
+
+    println("\nFirst set now modified:")
+    println("i1: ${i1} / ${i1[0].identify()} / ${typeof(i1).name}\n")
+    println("i2: ${i2} / ${i2[0].identify()} / ${typeof(i2).name}\n")
+    println("i3: ${i3} / ${i3[0].identify()} / ${typeof(i3).name}\n")
+
+    println("\nCopies made before modifications:")
+    println("i1c: ${i1c} / ${i1c[0].identify()} / ${typeof(i1c).name}\n")
+    println("i2c: ${i2c} / ${i2c[0].identify()} / ${typeof(i2c).name}\n")
+    println("i3c: ${i3c} / ${i3c[0].identify()} / ${typeof(i3c).name}\n")
+}