Objects or No Objects

[keean]

Discussion about records vs objects

[shelby3]

Please define the terms 'record' and 'object' and why they are not the same?

Our misunderstandings arise when we have different perspectives on meanings and default semantics.

[shelby3]

Link to potentially relevant discussion?

[keean]

If you read the OOHaskell paper you will find that an object is the fixed point of a record. However I in general prefer to separate data and functions.

A record is like a namespace, and a value of a record type is a particular implementation or value. In basic terms a record is like a C struct.

[shelby3]

@keean wrote:

If you read the OOHaskell paper you will find that an object is the fixed point of a record.

Are you referring to page 15, where setting the tail to the Unit type?

Again this seems to be a conclusion that is specific to Haskell's type system and how you are representing inheritance? And what does inheritance have to do with objects?

[keean]

I think we are agreed to have simple objects. No inheritance just interfaces/type classes. Closing as decided.

[shelby3]

You mean no virtual inheritance and no subclassing. But what about typeclass objects? And what about unions being subtypes? I don't think we can nail down those yet?

[keean]

I think the conclusion here is we are having objects, which will be at least simple objects. The other things are the subject of other threads, but to cover my thoughts, I don't think we need typeclass objects because we have union types. By no inheritance I mean you cannot extend object A. You can extend a typeclass but that is something different. We have interface inheritance, but not implementation inheritance.

[shelby3]

@shelby wrote:

I don't think we need typeclass objects because we have union types.

Disagree.