Thanks Chris for your explanation. Sunil. On Fri, Nov 26, 2010 at 6:16 PM, Chris Perkins <chrisperkin...@gmail.com>wrote:
> On Nov 26, 12:25 am, Sunil S Nandihalli <sunil.nandiha...@gmail.com> > wrote: > > I just realized that we don't need to use the with-symbol-macros when > using > > symbol-macrolet .. but the problem persists all the same.. I have > modified > > the gist to reflect this change.. > > Sunil. > > > > On Fri, Nov 26, 2010 at 10:35 AM, Sunil S Nandihalli < > > > > sunil.nandiha...@gmail.com> wrote: > > > Hello everybody, > > > I am not sure if this is the expected behaviour .. or I am using it > > > incorrectly .. The code is pasted at > > >https://gist.github.com/716293. > > > > > (ns symbol-macro-problem > > > > > (:require [clojure.contrib.macro-utils :as m])) > > > > > (defmacro sym-macro [& body] > > > > > `(m/symbol-macrolet [begin :begin > > > > > end :end] > > > > > (m/with-symbol-macros > > > > > (println begin) > > > > > ~...@body > > > > > (println end)))) > > > > > (defmacro display-local-bindings [] > > > > > `(do ~@(map (fn [x#] (list 'println [`'~x# x#])) (keys &env)))) > > > > > (sym-macro > > > > > (let [x 10] > > > > > (display-local-bindings))) > > > > > the above form is not passing the correct &env variable to the nested > > > macros .. It is turning out to be nil. The above code just prints > > > > > :begin > > > :end > > > > > while > > > > > (let [x 10] > > > (display-local-bindings)) > > > > > prints > > > > > [x 10] > > > > > I was expecting the code > > > > > (sym-macro > > > (let [x 10] > > > (display-local-bindings))) > > > > > to print > > > > > :begin > > > [x 10] > > > :end > > > > > but this is not happening since the &env variable that is being passed > to > > > (display-local-bindings) is nil when called inside a sym-macro > > > can somebody help me understand this. > > > > > Thanks, > > > Sunil. > > It seems to me that it is probably because the code in macro-utils > walks down through the forms and manually calls clojure.core/ > macroexpand-1. That calls clojure.lang.Compiler/macroexpand1, which is > where the local bindings are normally inserted calls to macros (i.e. > the display-local-bindings macro in this case). But it is being called > too soon - the compiler has not yet had its chance to walk down > through the enclosing forms and collect the local bindings, so it > doesn't know what they are. > > I'm pretty sure that macro-utils predates the addition of the &env > paramter. Since macro-utils takes such an aggressive approach to > macroexpansion - essentially reimplementing it entirely - it is not > too surprising that it would become out of sync with the built-in > expansion mechanism. > > - Chris > > -- > 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<clojure%2bunsubscr...@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
