static MaybeLens()
{
ExpectSome = new Lens <IMaybe <T>, T>(
maybe => maybe.OrElseThrow(
() => new InvalidOperationException("Some expected")),
value => maybe => value.ToSome());
}
ByKey <TKey, TValue>(TKey key)
{
return
(Lens.Create <IImmutableDictionary <TKey, TValue>, TValue>(
dictionary => dictionary[key],
value => dictionary => dictionary.SetItem(key, value)));
}
public static TType Set <TType, TValue>(
this TType instance,
Lens <TType, TValue> lens,
TValue value)
{
return(lens.Set(value)(instance));
}
public static TEntity RemoveByKey <TEntity, TKey, TValue>(
this TEntity instance,
Lens <TEntity, IImmutableDictionary <TKey, TValue> > lens,
TKey key)
{
return(instance.Set(lens.Lookup(key), Maybe <TValue> .None));
}
Location <TValue>(int x, int y)
{
return(Lens
.Create <IImmutableGrid <TValue>, TValue>(
grid => grid[x, y],
value => grid => grid.Set(x, y, value)));
}
Lookup <TKey, TValue>(TKey key, Func <TKey, TValue> defaultFactory)
{
return
(Lens.Create <IImmutableDictionary <TKey, TValue>, TValue>(
dictionary => dictionary.Lookup(key).OrElse(defaultFactory(key)),
// ReSharper disable once ImplicitlyCapturedClosure
value => dictionary => dictionary.SetItem(key, value)));
}
Lookup <TKey, TValue>(TKey key)
{
return
(Lens.Create <IImmutableDictionary <TKey, TValue>, IMaybe <TValue> >(
dictionary => dictionary.Lookup(key),
value => dictionary =>
{
return value
.Select(x => dictionary.SetItem(key, x))
.OrElse(() => dictionary.Remove(key));
}));
}
public static TValue Get <TType, TValue>(
this TType instance,
Lens <TType, TValue> lens)
{
return(lens.Get(instance));
}
Lookup <TEntity, TKey, TValue>(
this Lens <TEntity, IImmutableDictionary <TKey, TValue> > lens,
TKey key, Func <TKey, TValue> defaultFactory)
{
return(lens.With(Lookup(key, defaultFactory)));
}
Lookup <TType, TKey, TValue>(
this Lens <TType, IImmutableDictionary <TKey, TValue> > lens,
TKey key)
{
return(lens.With(Lookup <TKey, TValue>(key)));
}
public static Lens <TEntity, TValue> Location <TEntity, TValue>(
this Lens <TEntity, IImmutableGrid <TValue> > self, int x, int y)
{
return(self.With(Location <TValue>(x, y)));
}
public static Lens <TEntity, TValue> Location <TEntity, TValue>(
this Lens <TEntity, IImmutableGrid <TValue> > self, Vector location)
{
return(self.With(Location <TValue>(location.X, location.Y)));
}