Add functionStaticCall and functionDelegateCall methods to Address library

[k06a]

Consider having functionStaticCall and functionDelegateCall methods in Address library.

[frangio]

Thanks @k06a! Did you experiment with ways to avoid repeating the code? It seems the only thing that changes is the line with the actuall call. I wonder if Solidity's function types could be used here, and how gas would be affected.

[frangio]

@k06a Do you have any comments on the topic of avoiding the repeated code?

[k06a]

@frangio we could aggregate only call and delegatecall since they are both non-view methods, else view modifier will not work :(

[frangio]

Ah that's a good point.

I think we should at least be able to put the if conditional inside a separate private function that can be reused though. That would be a nice improvement. Could you try that out in this PR?

[k06a]

@frangio did, can't make it work with function pointers because of view modifiers.

[frangio]

@k06a This PR is great but you seem to have deleted the natspec documentation. 😄 Let me know if you can add it back, along with similar docs for the new functions, or if you want me to take care of it.

Thank you!

[k06a]

@frangio sorry about this, could someone help to restore it? You could simply push your own commits to my branch since I opened PR - it is allowed by github default settings :)

[frangio]

No problem, I'll take care of it.