Implementation of a user-defined coordinate system

[Mikayla Z. Grace]

Looking at some previous work done on vector coordinate systems, it seems that there have been two major trains of thought:  Either we should have each coordinate system be its own class or have a superclass that has subclasses within it (see PR #10109).  I'm favoring the former because of the issues raised in the comments in PR #10109. Via email contact with @Upabjojr who has done prior work on the topic (PR #9937), it seems that he too is interested in having individual classes.  

In the work with the superclass,there was some prior exploration in allowing for user-defined coordinate systems.  It's fairly clear how a user-defined coordinate system would be implemented with a superclass, but my question is about doing this within the framework of defining each coordinate system as an individual class.  It would make sense to let a user-defined system be its own class.  In PR #10074, @jbbskinny  discusses why he thinks a superclass is necessary for creating user-defined classes.  I'd love to get opinions on this topic regarding which method would be optimal.  Thanks for your time!

[Mikayla Z. Grace]

To clarify, I'm thinking about having classes for the standard coordinate systems and then one additional class for user-defined classes.  

[Francesco Bonazzi]

There should be one class for all coordinate systems because they are the same objects.

[Mikayla Z. Grace]

Okay, I think I must have misunderstood what you were saying.  Are you saying you think a single superclass is better than individual classes?

[Mikayla Z. Grace]

If one created subgroups, this be a case where instances would work?

[Francesco Bonazzi]

On Tuesday, 28 March 2017 22:06:41 UTC+2, Mikayla Z. Grace wrote:

Are you saying you think a single superclass is better than individual classes?

A single class, not a superclass.

[Alan Bromborsky]

Yes.

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