doc-src/IsarAdvanced/Codegen/Thy/examples/Codegen.hs
author wenzelm
Tue, 14 Oct 2008 15:16:11 +0200
changeset 28586 d238b83ba3fc
parent 25731 b3e415b0cf5c
permissions -rw-r--r--
renamed kill_all to kill, in conformance with atp_kill command; simplified/unified treatment of preferences; check_thread_manager: CRITICAL due to global ref; goal addressing via Thm.cprem_of; reduced NJ basis library stuff to bare minimum;

module Codegen where {

import qualified Nat;

class Null a where {
  nulla :: a;
};

heada :: forall a. (Codegen.Null a) => [a] -> a;
heada (x : xs) = x;
heada [] = Codegen.nulla;

null_option :: forall a. Maybe a;
null_option = Nothing;

instance Codegen.Null (Maybe a) where {
  nulla = Codegen.null_option;
};

dummy :: Maybe Nat.Nat;
dummy = Codegen.heada [Just (Nat.Suc Nat.Zero_nat), Nothing];

}