renamed Isar/isar_output.ML to Thy/thy_output.ML;
tuned messages;
Antiquote.scan_arguments (moved from here);
moved ML context stuff to from Context to ML_Context;
module Codegen where {
import qualified Nat;
class Null a where {
nulla :: a;
};
heada :: (Codegen.Null a) => [a] -> a;
heada (y : xs) = y;
heada [] = Codegen.nulla;
null_option :: Maybe b;
null_option = Nothing;
instance Codegen.Null (Maybe b) where {
nulla = Codegen.null_option;
};
dummy :: Maybe Nat.Nat;
dummy = Codegen.heada [Just (Nat.Suc Nat.Zero_nat), Nothing];
}