Retroactive: Noir contract scope

[kevaundray]

Problem

This is a retroactive issue for the contract scope.

We want Noir to be used as a private smart contract language. At the moment, we are only able to create private programs (libraries/binaries). We want a way to distinguish between a private program and a private contract because there is syntax and semantics that are allowed in contracts that are not allowed in programs.

For example, a private contract has the notion of a storage slot however, private programs do not inherently have this notion. Contracts will also have different visibility identifiers and function types. A Noir function in a program will eventually only be publicly visible or privately visible. This will in turn allow other Noir programs to call such a function (if publicly visible). Contracts on the other hand will have additional rules around what type of functions can call what functions and whether such calls get inlined or not. I am being particularly vague and will refer the reader to Solidities treatment of external and internal functions.

Proposed solution

The proposed solution is to implement the following syntax:

contract Foo {

   fn bar() {}
   
   fn baz() {}
}

The above introduces the contract keyword and defines a private smart contract named Foo. We have two functions defined in Foo which can be regarded as two Noir separate programs. One way to view "bar" and "baz" is that they are compiled as separate "main" functions.

Alternatives considered

No response

Additional context

No response

Submission Checklist

• Once I hit submit, I will assign this issue to the Project Board with the appropriate tags.

[kevaundray]

@iAmMichaelConnor Closing as this has been completed