I've solved my specific instance of this problem, I post here the details in the hope that the solution has a more general validity.
It seems that clojure.lang.RT gets confused when it is initialized (ie. <clinit> is called) and the classloader used to load the class itself is different from the current thread's context classloader. If I do: Thread.currentThread().setContextClassLoader(this.getClass.getClassLoader) just before making the call that cause Clojure runtime to be loaded and initialized, the error disappears. Francesco On Thursday, January 24, 2013 2:44:21 PM UTC+1, Francesco Bellomi wrote: > > (I repost this message because the original post I made yesterday seems to > have been rejected by googlegroups -- I have not received it and it is not > available online. > Sorry if this will result in a double post for some users.) > > Hi all, > > I'm writing a Scala library (currently alpha) to simplify the use of > Datomic (http://www.datomic.com) from Scala: > https://github.com/fbellomi/**datomic-scala<https://github.com/fbellomi/datomic-scala> > > I would like to make use of Scala compile-time macros in order to > statically type-check Datomic queries against a live database schema. > I need to call Datomic API from within the Scala compiler's macro > expansion stage, but it turns out that Clojure runtime fails to initialize > within that stage. > > A simple evaluation such as: > > clojure.lang.RT.T > > works fine from Scala's REPL, but fails from within Scala compiler, with > the following exception > > error: exception during macro expansion: > java.lang.**IllegalStateException: Attempting to call unbound fn: > #'clojure.core/refer > at clojure.lang.Var$Unbound.**throwArity(Var.java:43) > at clojure.lang.AFn.invoke(AFn.**java:39) > at clojure.lang.Var.invoke(Var.**java:415) > at clojure.lang.RT.doInit(RT.**java:449) > at clojure.lang.RT.<clinit>(RT.**java:318) > at .foo_impl(<console>:8) > > Not only the classpath, but also the thread context ClassLoader is the > same in both cases. > > I posted the details here: > > https://groups.google.com/forum/?hl=en&fromgroups=#!topic/scala-user/Bh_YmI6e-wY > > One could argue that this seems to be more of a Scala issue, but I did a > search and it turns out that there are other similar situations where the > Clojure runtime fails to initialize with the same error: > > - from within a Nutch plugin: > > https://groups.google.com/forum/?hl=en&fromgroups=#!searchin/clojure/nutch$20plugin/clojure/Fbqrk1T8SRg/CbQDd1yBvjYJ > > - trying to deploy an EJB > > https://groups.google.com/forum/?hl=en&fromgroups=#!searchin/clojure/ejb/clojure/FFe7Pf9TfXc/rxmYq6IoIjMJ > > - naming your project "clojure" in lein > http://osdir.com/ml/java-clojure-user/2012-04/msg00913.html > > > To further investigate my case, I tried to force the startup from core.clj > rather than from the precompiled classes. > Also in this case, the same call from the Scala repl works fine, whereas > the call from within the Scala macro expansion fails, with this: > > ava.lang.ClassCastException: clojure.core$fn cannot be cast to > clojure.lang.IFn, compiling:(clojure/core.clj:55) > at clojure.lang.Compiler.analyzeSeq(Compiler.java:6462) > at clojure.lang.Compiler.analyze(Compiler.java:6262) > at clojure.lang.Compiler.access$100(Compiler.java:37) > at clojure.lang.Compiler$DefExpr$Parser.parse(Compiler.java:518) > at clojure.lang.Compiler.analyzeSeq(Compiler.java:6455) > at clojure.lang.Compiler.analyze(Compiler.java:6262) > at clojure.lang.Compiler.analyze(Compiler.java:6223) > at clojure.lang.Compiler.eval(Compiler.java:6515) > at clojure.lang.Compiler.load(Compiler.java:6952) > at clojure.lang.RT.loadResourceScript(RT.java:359) > at clojure.lang.RT.loadResourceScript(RT.java:350) > at clojure.lang.RT.load(RT.java:429) > at clojure.lang.RT.load(RT.java:400) > at clojure.lang.RT.doInit(RT.java:436) > at clojure.lang.RT.<clinit>(RT.java:318) > at .foo_impl(<console>:8) > Caused by: java.lang.ClassCastException: clojure.core$fn cannot be cast to > clojure.lang.IFn > at clojure.lang.Var.fn(Var.java:392) > at clojure.lang.Var.invoke(Var.java:431) > at clojure.lang.AFn.applyToHelper(AFn.java:178) > at clojure.lang.Var.applyTo(Var.java:532) > at clojure.lang.Compiler.macroexpand1(Compiler.java:6366) > at clojure.lang.Compiler.analyzeSeq(Compiler.java:6441) > at clojure.lang.Compiler.analyze(Compiler.java:6262) > at clojure.lang.Compiler.access$100(Compiler.java:37) > at clojure.lang.Compiler$DefExpr$Parser.parse(Compiler.java:518) > at clojure.lang.Compiler.analyzeSeq(Compiler.java:6455) > at clojure.lang.Compiler.analyze(Compiler.java:6262) > at clojure.lang.Compiler.analyze(Compiler.java:6223) > at clojure.lang.Compiler.eval(Compiler.java:6515) > at clojure.lang.Compiler.load(Compiler.java:6952) > at clojure.lang.RT.loadResourceScript(RT.java:359) > at clojure.lang.RT.loadResourceScript(RT.java:350) > at clojure.lang.RT.load(RT.java:429) > at clojure.lang.RT.load(RT.java:400) > at clojure.lang.RT.doInit(RT.java:436) > at clojure.lang.RT.<clinit>(RT.java:318) > > Thanks in advance for any help or pointer. > > Francesco > -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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