Please forgive about this defn! macro, it does not seem to play well in practice.
I now share Konrad's thoughts : I don't know if what he want is feasible without changes in clojure, or use of clojure non-public APIs. 2009/3/3 Laurent PETIT <laurent.pe...@gmail.com> > Now that I rethink about it, wouldn't this version using eval be less than > ideal as far as AOT compilation is concerned ? > > 2009/3/3 Laurent PETIT <laurent.pe...@gmail.com> > > So there we are with a version of defn, which I called defn! because it is >> even more agressive than defn in its side effects, that could solve your >> problem : >> >> (defmacro defn! >> "Like defn, but first ensures that if name is bound to something (e.g. >> the name of a function >> in a 'used' or 'required' namespace, it is first unbound)." >> [name & body] >> `(do >> (clojure.core/ns-unmap *ns* (quote ~name)) >> (eval (quote (clojure.core/defn ~name ~...@body))))) >> >> I chose to use eval, even if it's not the usual recommended way, because I >> really wanted to not duplicate the logic in defn regarding definition of >> multiple arity functions, meta data, ... >> >> But I'm not sure it is correct to have twice ~name in the macro expansion. >> I thought that as name is expected to be the name for a symbol without >> evaluation (as is required for the name in defn), I could do this ? >> >> If you find this interesting, please feel free to add it to >> clojure-contrib. >> >> I think the same thing could be done for defmacro (defmacro!), ... and >> other defXYZ.. functions/macros as well .. ? >> >> HTH, >> >> -- >> Laurent >> >> >> 2009/3/3 Christophe Grand <christo...@cgrand.net> >> >> >>> Konrad Hinsen a écrit : >>> > On 03.03.2009, at 00:53, Laurent PETIT wrote: >>> > >>> > >>> >> I'm able to do that from the REPL when done one by one : >>> >> (clojure.core/ns-unmap *ns* (quote filter)) >>> >> (clojure.core/defn filter [] "oh my!") >>> >> >>> >> thus correctly redefining the binding of filter for the rest of use >>> >> by the ns >>> >> >>> >> But I can't manage to get it work from a macro (indeed not even >>> >> when directly called inside a do) : >>> >> >>> >> (do (clojure.core/ns-unmap *ns* (quote filter)) (clojure.core/defn >>> >> filter [] "my map!")) >>> >> >>> >> What is wrong with me ? (Something with def I still haven't >>> >> understood, I think) >>> >> >>> > >>> > I can only confirm your observation, and say that I don't understand >>> > it either! >>> > >>> In the first case, when you enter the second statement at the repl, >>> filter is unmapped already so the compiler understands that it must >>> create a var and intern it as my-ns/filter. >>> In the second case, both statements are bundled in one expression: when >>> the expression is compiled filter is still mapped in the current ns and >>> the compiler refuses to compile the def form. >>> >>> Adding an eval can make that works: >>> >>> (do >>> (clojure.core/ns-unmap *ns* (quote filter)) >>> (eval '(clojure.core/defn filter [] "my map!"))) >>> >>> >>> but it may be simpler to explore doing something like this: >>> >>> (do >>> (clojure.core/ns-unmap *ns* (quote filter)) >>> (clojure.lang.Var/intern *ns* 'filter (fn[] "my map!"))) >>> >>> >>> Christophe >>> >>> -- >>> Professional: http://cgrand.net/ (fr) >>> On Clojure: http://clj-me.blogspot.com/ (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 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 -~----------~----~----~----~------~----~------~--~---
