Remove Callback APIs

[erikzhang]

No description provided.

[erikzhang]

We don't need callback APIs if we have #2169.

[vncoelho]

we still would like to use some kind of callback like opeval.
Let's see.

[shargon]

If we remove the callbacks, we remove the possibility of doing lambda methods.

[erikzhang]

We have Pointer.

[erikzhang]

Go?

[shargon]

We need to remove this line first

https://github.com/neo-project/neo-vm/blob/defb2371d9a6a032bdea94e0c8b903a4729c9152/src/neo-vm/ExecutionEngine.cs#L298

But a I am worry about share pointers. How we will be isolated?

[erikzhang]

We need to remove this line first

Why should we remove this line? The Pointer should be used in the same contract only.

[shargon]

But then, how can we use a contract library with a method as an argument?

[erikzhang]

But then, how can we use a contract library with a method as an argument?

You can send the method name to it, just like what we did in Oracle contract.