My modest attempt at providing a Clojure-engine that is compliant with JSR 223 (the Java Scripting API). JSR 233 defines an API which makes it possible to interchangeably use any scripting-engine for which an implementation exists by exposing objects from the host application to the scripting engine.
Implementations exist for example for JS, Jython, JRuby, Groovy, Scala, and I think Clojure should not be left out. A long list of languages for which JSR 223 engines exists can be found at the Java scripting site.
NOTE: Requires ant 1.7.0+ (due to the service-task, which only exists since 1.7.0). Sorry for any inconvenience this might cause.
Builds clojure-jsr223.jar, which will contain the implementation of a JSR 223-compliant wrapper around Clojure. To compile and use it, you must have built the regular clojure.jar and added it to your classpath.
To build as an OSGi-component, you have to have the OSGi-framework stuff somewhere on your classpath. If you are using Equinox, org.eclipse.osgi_xxx.jar and org.eclipse.osgi.services_xxx.jar should be enough (they are found in the plugins-directory of your Eclipse installation directory); if you are using the Knopflerfish-framework, including framework.jar should suffice. The OSGi-bundle will include the contents of clojure.jar, which is why you need to point the Ant-flag clojure_jar to your clojure library (as opposed to the regular clojure-jsr223.jar, which requires clojure.jar to be on the classpath to run).
To test it, you can use something like:
jrunscript -cp clojure-jsr223.jar:/my/path/to/clojure.jar -l "Clojure"
Engine-internal bindings work.
Due to Clojure's design (which uses thread-local bindings rather than a dedicated context-object for different active runtimes), each ClojureScriptEngine has a dedicated thread on which it executes all operations.
Since I included parts of clojure.lang.Repl and use classes from the clojure.lang-package, all stuff is under the CPL (see CPL.txt).