Hello Lee, 2010/11/5 Lee Spector <lspec...@hampshire.edu>: > > On Oct 25, 2010, at 3:44 PM, Stuart Halloway wrote: >> * code path for using vars is now *much* faster for the common case, >> and you must explicitly ask for :dynamic bindability > > This has been bouncing around in my head for the last week or so, > occasionally colliding with the memory of Rich Hickey showing dynamic > rebinding of vars during a run (in a video, maybe on the ant simulation?) and > saying something like "It's a dynamic language!" (apparently with approval). > > I understand how this can be a big win on performance and I guess it's a > minor sacrifice since one will still be able ask for dynamic bindability with > only a little more clutter. > > But it leads me to ask whether it would be possible to simultaneously provide > a way to load libraries (e.g. in require or :require clauses of ns) while > specifying that certain vars in the library are to be defined as dynamically > bindable, even if they're not coded as such within the library. > > The reason I ask is that I often create a library and then want to use it in > a context in which I want one of the library's internal subfunctions to be > defined differently. So I load the library and then redefine the > subfunction's var (sandwiched between calls to ns, so I'm redefining the var > in the right namespace). [Perhaps this is not a recommended way to do > things? In any event I find it useful... Is there a better way that's not a > lot more work?]
If I understand well, you are re-def'ing the var. If so, then no problem, because you have mistaken "redefinition of a var" for "dynamic rebinding of a var". redefinition of a var will still be possible for non dynamically rebindable vars. (or we could then just stop to work on the REPL with Chas !) > > Anyway, I don't know ahead of time, when I write the library, which > particular vars I might want to redefine for any particular > application/experiment. But I'd rather not change the library's code between > experiments; I'd like that to be frozen and constant (and I use the exact > same file for many experiments). So if I wanted to make this work in all > possible use cases I'd have to designate *all* of my vars as dynamically, but > then: A) I'd have to clutter all of my vars with :dynamic specifications and, > 2) I'd lose the optimizations that this new feature of 1.3 alpha 2 are > providing (which sound worthwhile, being "*much* faster"). It would be nicer > if I could define everything in the library in the normal way, and have > everything loaded as not-dynamically-bindable in the usual case, but if I > could say in a particular application file that loads the library something > like: > > (ns foo > (:require [bar :dynamic baz bingo])) > > Or something to that effect -- I don't know if this exact syntax is > consistent with the various options in an ns/require form. > > The idea is that this would load bar but with the definitions of baz and > bingo marked as dynamically bindable, even though the code in bar.clj doesn't > ask for dynamic bindability. > > Possible? Desirable? > > Thanks! > > -Lee > > -- > 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 -- 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
