The Go 2 draft generics draft has been discussed a lot, especially contracts have drawn a lot of attention and other ways to limit the set of possible type were suggested.
Most discussions orbited around very basic polymorphic functions like polymorphic Min or a Map functions. I do consider a polymorphic Min function to be nothing more than a litmus test to generics: If a generic/polymorphic Min cannot be written the proposal is insufficient. But I probably would never write a polymorphic Min as a type specific Min is 3 lines and basically impossible to get wrong and just because Min looks nice under a proposal does not mean that the proposed solution will lead to good code where generic or polymorphic code would actually be beneficial: For complicated data structures and algorithms. At least the original proposal mentions a generic Graph data structure. Still without showing how e.g. DFS, BFS, Shortest Paths would be a) implemented and b) used. I think it would be good if we could see how different proposals (and especially the official one) would affect how generic code is written and used. Especially code which is hard to get right and really benefits from a "generic" implementation. I'd like to see generic/polymorphic: - Image manipulation (scaling, convolution, etc.) for various color models - Balanced trees (AVL or Red-Black) - Matrices of bool, int, float32/64, complex with inversion, LR-decomposition, eigenvalues - Fast Fourier Transformation (with ints, float32/64, complex64/128 and my float24 inputs) - Graph algorithms (DFS, BFS, Dijkstra, Bellman-Ford, Floyd-Warshall) (feel free to add stuff from your field here). How would a package graph with a generic Graph data structure and accompanying algorithms look like? How would I use such a generic algorithm with nodes of my own type? How would I be using a generic 2d FFT package when my inputs is complex128 and how if inputs are float32? I think that answers to these questions would be much more helpful in evaluating generics than the current focus on the syntax of Min and whether contracts can be done trough interfaces. Let's start with Dijkstra and the Graph example of the original proposal: How would the implementation look like and how would my code use this implementation? V. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
