doc-src/IsarAdvanced/Codegen/Thy/examples/Codegen.hs
author berghofe
Wed, 07 May 2008 10:56:52 +0200
changeset 26803 0af0f674845d
parent 25731 b3e415b0cf5c
permissions -rw-r--r--
- Explicitely passed pred_subset_eq and pred_equals_eq as an argument to the to_set and to_pred attributes, because it is no longer applied automatically - Manually applied predicate1I in proof of accp_subset, because it is no longer part of the claset - Replaced psubset_def by less_le

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];

}