public static State <S, S> Get <S>(Func <S, S> f)
{
if (f == null)
{
throw new ArgumentNullException("f");
}
return((S state) => StateResult.Create <S, S>(state, f(state)));
}
public static State <S, U> Select <S, T, U>(this State <S, T> self, Func <T, U> map)
{
if (map == null)
{
throw new ArgumentNullException("map");
}
return((S state) =>
{
var resT = self(state);
return StateResult.Create <S, U>(resT.State, map(resT.Value));
});
}
public static State <S, A> With <S, A>(this State <S, A> self, Func <S, S> f)
{
if (f == null)
{
throw new ArgumentNullException("f");
}
return((S state) =>
{
var res = self(state);
return StateResult.Create <S, A>(f(res.State), res.Value);
});
}
public static State <S, Unit> Put <S>(S state)
{
return(_ => StateResult.Create <S, Unit>(state, Unit.Default));
}
public static State <S, S> Get <S>()
{
return((S state) => StateResult.Create <S, S>(state, state));
}