69 lines
1.6 KiB
C#
69 lines
1.6 KiB
C#
// Normally we wouldn't want to disable Nullable references, but in this case we want to.
|
|
// We're assuming that if you're following Maybe conventions, you won't be hitting null ref exceptions.
|
|
#pragma warning disable CS8601
|
|
namespace FruityFoundation.Base.Structures;
|
|
|
|
[Serializable]
|
|
public struct Maybe<T>
|
|
{
|
|
private readonly T _value;
|
|
public readonly bool HasValue;
|
|
|
|
private Maybe(T val = default!, bool hasValue = true)
|
|
{
|
|
_value = val;
|
|
HasValue = hasValue;
|
|
}
|
|
|
|
public T Value
|
|
{
|
|
get
|
|
{
|
|
if (!HasValue)
|
|
throw new InvalidOperationException($"{nameof(Maybe<T>)} value is empty");
|
|
|
|
return _value;
|
|
}
|
|
}
|
|
|
|
public T OrValue(T orVal) =>
|
|
HasValue ? Value : orVal;
|
|
|
|
public bool Try(out T val)
|
|
{
|
|
val = HasValue ? Value : default;
|
|
|
|
return HasValue;
|
|
}
|
|
|
|
public T OrThrow(string msg) =>
|
|
HasValue ? Value : throw new Exception(msg);
|
|
|
|
public Maybe<TOutput> Map<TOutput>(Func<T, TOutput> transformer) =>
|
|
HasValue
|
|
? Maybe<TOutput>.Create(transformer(Value))
|
|
: Maybe<TOutput>.Empty();
|
|
|
|
public object ToDbValue() =>
|
|
HasValue && Value is not null
|
|
? Value
|
|
: DBNull.Value;
|
|
|
|
public static Maybe<T> Create(T val, bool hasValue = true) => new(val, hasValue);
|
|
|
|
public static Maybe<T> Create(T val, Func<T, bool> hasValue) => new(val, hasValue(val));
|
|
|
|
public static Maybe<T> Empty() => new(default!, hasValue: false);
|
|
|
|
public static implicit operator Maybe<T>(T val) => Create(val);
|
|
|
|
public static explicit operator T(Maybe<T> val) => val.Value;
|
|
|
|
public override string ToString()
|
|
{
|
|
return (Try(out var val)
|
|
? val?.ToString()
|
|
: base.ToString())!;
|
|
}
|
|
}
|