CDE

Task/Add-a-variable-to-a-class-instance-at-runtime/Common-Lisp/add-a-variable-to-a-class-instance-at-runtime-1.lisp

@@ -0,0 +1,5 @@
+(defun augment-instance-with-slots (instance slots)
+  (change-class instance
+                (make-instance 'standard-class
+                  :direct-superclasses (list (class-of instance))
+                  :direct-slots slots)))

Task/Add-a-variable-to-a-class-instance-at-runtime/Common-Lisp/add-a-variable-to-a-class-instance-at-runtime-2.lisp

@@ -0,0 +1,12 @@
+CL-USER> (let* ((instance (make-instance 'foo :bar 42 :baz 69))
+                (new-slots '((:name xenu :initargs (:xenu)))))
+           (augment-instance-with-slots instance new-slots)
+           (reinitialize-instance instance :xenu 666)
+           (describe instance))
+#<#<STANDARD-CLASS NIL {1003AEE2C1}> {1003AEE271}>
+  [standard-object]
+
+Slots with :INSTANCE allocation:
+  BAR   = 42
+  BAZ   = 69
+  XENU  = 666

Task/Add-a-variable-to-a-class-instance-at-runtime/D/add-a-variable-to-a-class-instance-at-runtime-1.d

@@ -0,0 +1,31 @@
+struct Dynamic(T) {
+    private T[string] vars;
+
+    @property T opDispatch(string key)() pure nothrow {
+        return vars[key];
+    }
+
+    @property void opDispatch(string key, U)(U value)/*pure*/ nothrow {
+        vars[key] = value;
+    }
+}
+
+void main() {
+    import std.variant, std.stdio;
+
+    // If the type of the attributes is known at compile-time:
+    auto d1 = Dynamic!double();
+    d1.first = 10.5;
+    d1.second = 20.2;
+    writeln(d1.first, " ", d1.second);
+
+
+    // If the type of the attributes is mixed:
+    auto d2 = Dynamic!Variant();
+    d2.a = "Hello";
+    d2.b = 11;
+    d2.c = ['x':2, 'y':4];
+    d2.d = (int x) => x ^^ 3;
+    writeln(d2.a, " ", d2.b, " ", d2.c);
+    immutable int x = d2.b.get!int;
+}

Task/Add-a-variable-to-a-class-instance-at-runtime/D/add-a-variable-to-a-class-instance-at-runtime-2.d

@@ -0,0 +1,13 @@
+import std.stdio, std.variant, std.conv;
+
+struct Dyn {
+    Variant[string] data;
+    alias data this;
+}
+
+void main(string[] args) {
+    Dyn d;
+    const attribute_name = text("attribute_", args.length);
+    d[attribute_name] = "something";
+    writeln(d[attribute_name]);
+}

Task/Add-a-variable-to-a-class-instance-at-runtime/Elena/add-a-variable-to-a-class-instance-at-runtime.elena

@@ -0,0 +1,27 @@
+#subject foo.
+
+#class FieldContainer
+{
+    #field theValue.
+
+    #method foo'set : anObject
+    [
+        theValue := anObject.
+    ]
+
+    #method foo'get = theValue.
+}
+
+#symbol Program =
+[
+    #var anObject := 234.
+
+    // adding a field
+    anObject := anObject &= FieldContainer.
+
+    anObject foo'set:"bar".
+
+    'program'Output << anObject << ".foo=" << anObject foo.
+
+    'program'input get.
+].