Thanks for the feedback. I will check to see if there's some way to query for capabilities, but I doubt it, given the client code.
The client code does most of this version checking in one class, so that seems localized enough and I think it will be straight forward. Maybe if I stumble on a better way to do this, I'll share. Evan On Thursday, July 11, 2019 at 3:09:09 AM UTC-10, Greg Hendershott wrote: > > Some systems provide a way to query for a capability: COM has > QueryInterface, Racket dynamic-require, Emacs fboundp, and so on. When > such a query method is available, you can simply ask for the thing you > need or prefer. If it's available, great. If not, act appropriately: > Fail, or use your own "back fill" that does something similar or is just > a no-op, or whatever is appropriate. > > [IMHO this is more sensible than using version numbers as proxies for > the thing you really care about. Especially lawyerly systems like > so-called semantic versioning. But I digress. :)] > > The Racket flavor is something like the following. Let's say > some/module/path maybe has a new fribble function. If that's not > present, or if indeed that whole module isn't even installed, we want to > use our own our-fribble function as a default: > > (define (our-fribble _x) > 'some-default-value) > > (define fribble > (with-handlers ([exn:fail? (λ _ our-fribble)]) > (dynamic-require 'some/module/path > 'fribble))) > > For example, I use this and also Emacs' fboundp in Racket Mode, to > support various versions of Racket and Emacs, both. > > > I don't know if/how this would help your case. Their API uses the > futzing-with-version-numbers approach. Even so, _maybe_ you'd want to > localize the version number checks in one module, which provides the > functions for your other code to use? The functions will end up being > either the real broker thing, or your own default. > -- 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/54fdaf8b-2233-475e-b6ed-78c8fdeeeabf%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
