langs a-z

Task/Abstract-type/Perl-6/abstract-type.pl6

@@ -0,0 +1,23 @@
+use v6;
+
+role A {
+    # must be filled in by the class it is composed into
+    method abstract() { ... };
+
+    # can be overridden in the class, but that's not mandatory
+    method concrete() { say '# 42' };
+}
+
+class SomeClass does A {
+    method abstract() {
+        say "# made concrete in class"
+    }
+}
+
+my $obj = SomeClass.new;
+$obj.abstract();
+$obj.concrete();
+
+# output:
+# made concrete in class
+# 42