Hi, Am 25.09.2009 um 22:49 schrieb Constantine Vetoshev:
(defmacro def-with-db-macro [macro-name open-fn close-fn]
`(defmacro ~macro-name [[var# & open-args#] & body#]
`(let [~var# (apply ~'~open-fn [...@open-args#])]
(try
~...@body#
(finally (~'~close-fn ~var#))))))
The problem is, that you quote the symbol you inject into the inner defmacro. Hence it does not get resolved. The solution in this case seems to be to syntax-quote the symbol correctly before injection. Replace the two ~'~ with ~~ and call the macro as (def-with-db-macro with-foo `open-foo `close-foo). This correctly resolves the symbols in the namespace calling def-with-db-macro and injects them into the with- foo expansion. I haven't really tested this, but it seems to be consistent with the macro machinery.
While searching for a workaround, I thought maybe I could capture the functions I need during expansion of def-with-db-macro, but kept getting a useless exception. I ended up reducing that problem to this: (let [f1 #(inc %)] (defmacro m1 [x] `(~f1 ~x))) (m1 12) => No message. [Thrown class java.lang.ExceptionInInitializerError]
This seems indeed useless at a first glance, but looking down the cause trace usually shows the real problem.
Sincerely Meikel
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