CDE

Task/Constrained-genericity/D/constrained-genericity-1.d

@@ -0,0 +1,21 @@
+template IsEdible(T) {
+    enum IsEdible = is(typeof(T.eat()));
+}
+
+struct FoodBox(T) if (IsEdible!T) {
+    T[] food;
+    alias food this;
+}
+
+struct Carrot {
+    void eat() {}
+}
+
+static struct Car {}
+
+void main() {
+    FoodBox!Carrot carrotsBox; // OK
+    carrotsBox ~= Carrot();    // Adds a carrot
+
+    //FoodBox!Car carsBox;     // Not allowed
+}

Task/Constrained-genericity/D/constrained-genericity-2.d

@@ -0,0 +1,17 @@
+interface IEdible { void eat(); }
+
+struct FoodBox(T : IEdible) {
+    T[] food;
+    alias food this;
+}
+
+class Carrot : IEdible {
+    void eat() {}
+}
+
+class Car {}
+
+void main() {
+    FoodBox!Carrot carrotBox; // OK
+    //FoodBox!Car carBox;     // Not allowed
+}