Overloading operator for generics C# [duplicate]

Question

I would like to create a procedure class that supports connecting to another procedure like so: a|b|c|d (this should result a procedure takes a's input type, and give d's output type)

class Procedure<I,O>
{
  public Func<I,O> func;
  public Procedure(Func<I, O> func)
  { this.func = func; }
  public static Procedure<I, O> operator| (Procedure<I, M> proc1, Procedure<M, O> proc2)
  { return new Procedure<I,O>((x) => proc2.Process(proc1.Process(x))); }
  public O Process(I input)
  { return func.Invoke(input); }
}

The compiler complains it can't find M. Normally I would add after the method name, however in this case it gets recognized as part of the operator name. What do?

Just a side note, I'm trying to move my Scala lib into C# here.

myroman · Accepted Answer · 2015-03-20 03:52:14Z

2

You can't do this because M is not a type parameter of Procedure class and you cannot define it for operator | - it's C# limitation. To tackle this use a method, not operator:

public static Procedure<I, O> Composition<M>(Procedure<I, M> proc1, Procedure<M, O> proc2)
    {
        return new Procedure<I, O>((x) => proc2.Process(proc1.Process(x)));
    }

answered Mar 20, 2015 at 3:52

myroman

5726 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Zuoanqh Over a year ago

I actually said I know this in the question.. it was more asking how to do using operator. but thanks!

myroman Over a year ago

I missed that you mentioned it, sorry

Phil Wright · Accepted Answer · 2015-03-20 03:57:29Z

1

The rules of overriding a binary operation are that one of the two parameters must be the same type as the enclosing class. So either proc1 or proc2 must be of type Procedure< I,O>. This precludes it being able to achieve what you need.

I can see what you are trying to do but it cannot be done in C#. The compiler will generate just a single operator override implementation for each class that is generated from the unique generic parameters. In your case you would need the compiler to automatically generic as many as are needed to handle all the intermediate types used.

answered Mar 20, 2015 at 3:57

Phil Wright

23k16 gold badges88 silver badges142 bronze badges

Collectives™ on Stack Overflow

Overloading operator for generics C# [duplicate]

2 Answers 2

2 Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Linked

Related