Thanks It is working with (defmethod mycomp ~m [~'_] ~m)) _ is also clojure valid symbol identifier. I miss that point.
Br, Mamun On Tuesday, December 26, 2017 at 11:59:23 PM UTC+1, Gary Verhaegen wrote: > > The spec is correct; your code is wrong and I don't know how you got your > expansion there. > > $ lein try org.clojure/clojure 1.9.0 > nREPL server started on port 55018 on host 127.0.0.1 - nrepl:// > 127.0.0.1:55018 > REPL-y 0.3.7, nREPL 0.2.12 > Clojure 1.8.0 > Java HotSpot(TM) 64-Bit Server VM 1.8.0_144-b01 > Docs: (doc function-name-here) > (find-doc "part-of-name-here") > Source: (source function-name-here) > Javadoc: (javadoc java-object-or-class-here) > Exit: Control+D or (exit) or (quit) > Results: Stored in vars *1, *2, *3, an exception in *e > > user=> (defmulti mycomp (fn [v] v)) > #'user/mycomp > user=> (defmacro defcomp [m] > #_=> `(defmethod mycomp ~m > #_=> [_] > #_=> ~m > #_=> ) > #_=> ) > #'user/defcomp > user=> (defcomp :test) > > CompilerException java.lang.RuntimeException: Can't use qualified name as > parameter: user/_, compiling:(null:1:1) > user=> (macroexpand '(defcomp test)) > (. user/mycomp clojure.core/addMethod test (clojure.core/fn [user/_] test)) > user=> > > The problem is that you have not protected the _, so it gets expanded to > the local namespace (user/_ in my case here, com.mxsys.psql.component/_ > in yours). You want: > > user=> (defmacro defcomp [m] `(defmethod mycomp ~m [~'_] ~m)) > #'user/defcomp > user=> (defcomp :test) > #multifn[mycomp 0x545609d8] > user=> (macroexpand '(defcomp :test)) > (. user/mycomp clojure.core/addMethod :test (clojure.core/fn [_] :test)) > user=> > > Notice how the underscore is escaped as ~'_ to escape from the syntax > quote and place a literal underscore symbol. > -- 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 unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
