My negative experience with debugging touches on a number of things, but the biggest is the way that lazy evaluation makes it hard to determine cause and effect while debugging. This has been a problem, and I've had to do a lot of (prn) calls to try and identify what's going on.
I eventually have figured out everything, but it's been a challenge I wouldn't recommend to a new coder without a lot of experience to draw upon! I'm not sure how to address it; but this is an issue that may ultimately have Clojure relegated as a "language for experts". I want it to be a language for everyone. On Mon, Jun 29, 2009 at 5:35 PM, Richard Newman <holyg...@gmail.com> wrote: > > > at the risk of sounding negative and (-; thus getting > > "moderated" ;-) ... I'm very interested in taking another stab at > > clojure after putting it down for a while, but I had real trouble > > debugging my programs. I'm looking for advice and/or an approach. > > Aside from two areas — JVM problems, such as with gen-class'ed > classes, and exceptions occurring in Java code — I've found that the > best general approach is to build small, functional programs. > > If every function is only a few lines long, and stands mostly alone, > you can build from the bottom up and rely on your foundations. Test as > you go, by hand or automatically — I find that automation is much less > important with functional programming, because there are fewer knock- > on effects of changes, but that's another kettle of fish — but if you > keep most of your program free of side effects, composed of small > functions, you should find that debugging in the large is greatly > reduced. > > No side effects mean that the only time you can have a bug is if you > get the wrong output from your function for the inputs you provided; > debugging in that case means inspecting your function, and maybe > navigating outwards the tree of calls it makes to other pure > functions. Add tracing until you find the function that's returning > the wrong thing, and fix it. > > If you're finding that you're managing a lot of state, and thus have > trouble debugging, then you're probably not taking a sufficiently > functional approach. (A big hint is if you find yourself wanting a > stepping debugger to watch values change. It's the "change" part > that's worrying!) > > If that's not your problem, could you elaborate so that we might all > opine? :) > > -R > > > -- Howard M. Lewis Ship Creator of Apache Tapestry Director of Open Source Technology at Formos --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
