Hello. I have a project where I am needing to represent vectors (in the mathematical sense), points, and colors. Both the vectors and points will be 3D. I'm having trouble knowing what's an idiomatic way to represent and interact with data types that are similar but different.
In general, I could simply all represent them with a list or vector (in the Racket sense). So I could have: (define (vector i j k) #(i j k)) (define (point x y z) #(x y z)) Then I could readily use the existing vector functions, such as vector-map without having to define my own. But I don't super like this because I have to define my own accessor functions like vector-i and point-y and also don't get predicates like vector? for free. Another way is that I could use structs, but then I'm stuck implementing things myself and across the structs. To avoid the latter point, I could use pattern matching. So something like: (struct vector (i j k)) (struct point (x y z)) (define (tuple-map proc tuple) (match tuple [(struct vector (i j k)) (vector (proc (vector-i tuple)) (proc (vector-j tuple)) (proc (vector-k tuple)))] [(struct point (x y z)) (point (proc (point-x tuple)) (proc (point-y tuple)) (proc (point-z tuple)))] [(struct color (r g b)) (color (proc (color-r tuple)) (proc (color-g tuple)) (proc (color-b tuple)))])) But of course, this map doesn't take multiple tuples. And this feels awkward, because I'll need to implement other things, like fold. Map and fold would be used in defining new operators on vectors and points, like addition, normalization (for vectors only), etc. The ideal thing would be that I could define a struct for these types, that had the accessor functions like vector-i and predicates likes vector? but was actually represented by a vector (in the Racket sense) underneath the hood. Does something like this exist in Racket (not classes please). In F#, I did this same thing using F#'s records for the vector, point, and color data types, and they inherited an ITuple interface (F#'s immutable, functional data types can implement interfaces). Can Racket's stucts inherit from interfaces? Is there something I can do with generics? Thanks for any help on this design. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/8214d59a-d6de-445f-b203-b0a2b8c374cdn%40googlegroups.com.