samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/interface2.t

@@ -0,0 +1,38 @@
+
+IO = terralib.includec("stdio.h")
+local Class = require("lib/javalike")
+
+HasFoo = Class.interface({ foo = int -> int })
+
+struct A {
+	a : int
+}
+
+terra A:foo(a : int) : int
+	return 1
+end
+Class.implements(A,HasFoo)
+
+struct B {}
+Class.extends(B,A)
+
+
+struct C {}
+Class.extends(C,B)
+
+terra C:foo(a : int) : int
+	return 3
+end
+
+terra hasfoo(a : &HasFoo)
+	return a:foo(3)
+end
+
+terra testit()
+	var a = A.alloc()
+	var b = B.alloc()
+	var c = C.alloc()
+	return hasfoo(a) + hasfoo(b) + hasfoo(c)
+end
+
+assert(testit() == 5)