C#•3y ago

How does this delegate work?

Given this delegate:

public delegate (T Value, int Seed) Generator<T>(int seed)

public delegate (T Value, int Seed) Generator<T>(int seed)

How this function return a Generator delegate?

public static Generator<int> NextInt = (seed) =>
{
    seed ^= seed >> 13;
    seed ^= seed << 18;
    int result = seed & 0x7fffffff;
    return (result, result);
};

public static Generator<int> NextInt = (seed) =>
{
    seed ^= seed >> 13;
    seed ^= seed << 18;
    int result = seed & 0x7fffffff;
    return (result, result);
};

8 Replies

Thinker•3y ago

Well, NextInt is a static field with the type Generator<int>, and it's initialized with a lambda expression which matches the Generator<int> delegate.

zxa4fdOP•3y ago

This seems correct; I thought NextInt was a function and not a field

Thinker•3y ago

It doesn't have () so it's not a method

zxa4fdOP•3y ago

This NextInt property is used here in what seems to be LINQ:

public static Generator<bool> NextBool =>
    from i in NextInt
    select i % 2 == 0;

public static Generator<bool> NextBool =>
    from i in NextInt
    select i % 2 == 0;

May I know how this is working? NextInt doesn't seem to be IEnumerable

Thinker•3y ago

That shouldn't work

zxa4fdOP•3y ago

This is an example from a book, so maybe the context will help? Will it really not work?

zxa4fdOP•3y ago

Here is the code: https://github.com/la-yumba/functional-csharp-code/blob/master/Examples/Chapter12/Generator.cs

Thinker•3y ago

yeah no this doesn't make sense

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How does this delegate work?

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