Initial data commit

Task/Abstract-type/Genyris/abstract-type-1.genyris

@@ -0,0 +1,4 @@
+class AbstractStack()
+   def .valid?(object) nil
+
+tag AbstractStack some-object # always fails

Task/Abstract-type/Genyris/abstract-type-2.genyris

@@ -0,0 +1,8 @@
+class StackInterface()
+   def .valid?(object)
+      object
+         and
+            bound? .enstack
+            is-instance? .enstack Closure
+            bound? .destack
+            is-instance? .destack Closure

Task/Abstract-type/Genyris/abstract-type-3.genyris

@@ -0,0 +1,9 @@
+class XYZstack(Object)
+    def .init()
+        var .items ()
+    def .enstack(object)
+        setq .items (cons object .items)
+    def .destack()
+        var tmp  (car .items)
+        setq .items (cdr .items)
+        tmp

Task/Abstract-type/Genyris/abstract-type-4.genyris

@@ -0,0 +1 @@
+tag StackInterface (XYZstack(.new))