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();
}
}
/**
* Will invoke the "update" function of the script loaded by this engine with the provided list of
* parameters.
*/
public static void executeScript(Object... args) {
try {
js_invocable.invokeFunction("update", args);
} catch (ScriptException se) {
se.printStackTrace();
} catch (NoSuchMethodException nsme) {
nsme.printStackTrace();
}
}
/** Will load the script source from the provided filename. */
public static void loadScript(String script_name) {
try {
js_engine.eval(new java.io.FileReader(script_name));
} catch (ScriptException se) {
se.printStackTrace();
} catch (java.io.IOException iox) {
iox.printStackTrace();
}
}
