@import Foundation;


NS_ASSUME_NONNULL_BEGIN

@interface Function<__contravariant InType, __covariant OutType> : NSObject
{
    // interestingly, this does work here (though OutType & InType are not available in the @implementation)
    OutType (^_block)(InType);
}

- (instancetype)initWithBlock:(OutType (^)(InType))block;

- (OutType)evaluateAt:(InType)value;

@end

NS_ASSUME_NONNULL_END