Add tasks for all the new languages

Task/Abstract-type/Lingo/abstract-type-1.lingo

@@ -0,0 +1,5 @@
+on extendAbstractClass (instance, abstractClass)
+  -- 'raw' instance of abstract class is made parent ("ancestor") of the
+  -- passed instance, i.e. the passed instance extends the abstract class
+  instance.setProp(#ancestor, abstractClass.rawNew())
+end

Task/Abstract-type/Lingo/abstract-type-2.lingo

@@ -0,0 +1,12 @@
+-- instantiation of abstract class by calling its constructor fails
+on new (me)
+  -- optional: show error message as alert
+  _player.alert("Error:"&&me.script&&" is an abstract class")
+  return VOID
+end
+
+on ring (me, n)
+  repeat with i = 1 to n
+    put me.ringtone
+  end repeat
+end

Task/Abstract-type/Lingo/abstract-type-3.lingo

@@ -0,0 +1,11 @@
+property ringtone
+
+on new (me)
+  extendAbstractClass(me, script("AbstractClass"))
+  me.ringtone = "Bell"
+  return me
+end
+
+on foo (me)
+  put "FOO"
+end

Task/Abstract-type/Lingo/abstract-type-4.lingo

@@ -0,0 +1,10 @@
+obj = script("MyClass").new()
+obj.ring(3)
+-- "Bell"
+-- "Bell"
+-- "Bell"
+
+-- this fails
+test = script("AbstractClass").new()
+put test
+-- <Void>

Task/Abstract-type/Lingo/abstract-type-5.lingo

@@ -0,0 +1,12 @@
+on implementsInterface (instance, interfaceClass)
+  interfaceFuncs = interfaceClass.handlers()
+  funcs = instance.handlers()
+  repeat with f in interfaceFuncs
+    if funcs.getPos(f)=0 then
+      -- optional: show error message as alert
+      _player.alert("Error:"&&instance.script&&"doesn't implement interface"&&interfaceClass)
+      return FALSE
+    end if
+  end repeat
+  return TRUE
+end

Task/Abstract-type/Lingo/abstract-type-6.lingo

@@ -0,0 +1,3 @@
+on foo
+on bar
+on foobar

Task/Abstract-type/Lingo/abstract-type-7.lingo

@@ -0,0 +1,20 @@
+on new (me)
+  -- if this class doesn't implement all functions of the
+  -- interface class, instantiation fails
+  if not implementsInterface(me, script("InterfaceClass")) then
+    return VOID
+  end if
+  return me
+end
+
+on foo (me)
+  put "FOO"
+end
+
+on bar (me)
+  put "BAR"
+end
+
+on foobar (me)
+  put "FOOBAR"
+end

Task/Abstract-type/Lingo/abstract-type-8.lingo

@@ -0,0 +1,3 @@
+obj = script("MyClass").new()
+put obj -- would show <Void> if interface is not fully implemented
+-- <offspring "MyClass" 2 171868>