struct->vector isomorphism

[jackfirth]

Given a structure id, it should be possible to construct an isomoprhism between struct instances of that type and vectors

> (struct position (x y))
> (lens-view (struct->vector-lens position) (position 1 2))
'#(1 2)

[AlexKnauth]

I think using the name struct->vector-lens would be confusing because struct->vector puts the extra struct:position symbol at the beginning. struct->list-lens would work for this though, because struct->list doesn't include that symbol.

[jackfirth]

I forgot about struct->vector, the lens form should match whatever that does. A struct->list lens would have to be careful of the fact that struct->list is only available in racket 6.3, I'd like to keep supporting the versions we do now.

[AlexKnauth]

We could support struct->list-lens without relying on 6.3 if we looked at the struct-info and used the normal accessors, which we should probably be doing anyway.

[jackfirth]

Agreed, that would probably be the best way to do this.

[AlexKnauth]

Should this issue be closed because of #266 ?