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import javax.script.*;
public class JSR223Example {
public static void main(String[] args) {
//Script Engine instantiation using ServiceProvider - this will
//look in the classpath for a file
// /META-INF/services/javax.script.ScriptEngineFactory
//where the AbclScriptEngineFactory is registered
ScriptEngine lispEngine = new ScriptEngineManager().getEngineByExtension("lisp");
//Alternatively, you can directly instantiate the script engine:
//ScriptEngineManager scriptManager = new ScriptEngineManager();
//scriptManager.registerEngineExtension("lisp", new AbclScriptEngineFactory());
//ScriptEngine lispEngine = scriptManager.getEngineByExtension("lisp");
//(thanks to Peter Tsenter for suggesting this)
//Accessing variables
System.out.println();
System.out.println("*package* = " + lispEngine.get("*package*"));
Object someValue = new Object();
lispEngine.put("someVariable", someValue);
System.out.println("someVariable = " + lispEngine.get("someVariable"));
try {
//Interpretation (also from streams)
lispEngine.eval("(defun hello (arg) (print (list arg someVariable)) (terpri))");
//Direct function invocation
((Invocable) lispEngine).invokeFunction("hello", "world");
//Implementing a Java interface in Lisp
lispEngine.eval("(defun compare-to (&rest args) 42)");
Comparable c = ((Invocable) lispEngine).getInterface(java.lang.Comparable.class);
System.out.println("compareTo: " + c.compareTo(null));
//Compilation!
lispEngine.eval("(defmacro slow-compiling-macro (arg) (dotimes (i 1000000) (incf i)) `(print ,arg))");
long millis = System.currentTimeMillis();
lispEngine.eval("(slow-compiling-macro 42)");
millis = System.currentTimeMillis() - millis;
System.out.println("interpretation took " + millis);
millis = System.currentTimeMillis();
CompiledScript cs = ((Compilable) lispEngine).compile("(slow-compiling-macro 42)");
millis = System.currentTimeMillis() - millis;
System.out.println("compilation took " + millis);
millis = System.currentTimeMillis();
cs.eval();
millis = System.currentTimeMillis() - millis;
System.out.println("evaluation took " + millis);
millis = System.currentTimeMillis();
cs.eval();
millis = System.currentTimeMillis() - millis;
System.out.println("evaluation took " + millis);
//Ecc. ecc.
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (ScriptException e) {
e.printStackTrace();
}
}
}
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