Hi all,

I'm reading "Programming Clojure" and I was comparing some languages I use for some simple code. I noticed that the clojure implementations were the slowest in each case. For instance,

Python - hello.py

def hello_world(name):
  print "Hello, %s" % name

hello_world("world")

and result,

$ time python hello.py
Hello, world

real    0m0.027s
user    0m0.013s
sys 0m0.014s

Java - hello.java

import java.io.*;

public class hello {
  public static void hello_world(String name) {
    System.out.println("Hello, " + name);
  }

  public static void main(String[] args) {
    hello_world("world");
  }
}

and result,

$ time java hello
Hello, world

real    0m0.324s
user    0m0.296s
sys 0m0.065s

and finally,

Clojure - hellofun.clj

(defn hello-world [username]
  (println (format "Hello, %s" username)))

(hello-world "world")

and results,

$ time clj hellofun.clj 
Hello, world

real    0m1.418s
user    0m1.649s
sys 0m0.154s

Thats a whole, garangutan 1.4 seconds!

Does anyone have pointers on what the cause of this could be? Is Clojure really that slow, or are there JVM tricks et al that need to be used in order to speed up execution?

More importantly - isn't this huge difference in performance going to be an issue at some point? (I mean, lets say I was using Clojure for a production system - the gain I get in using lisp seems completely offset by the performance issues I can see here).

The machine used here is a 2007 Macbook Pro running Snow Leopard, a 2.16Ghz Intel C2D and 2G DDR2 SDRAM.

BTW, the clj script I'm using is from here and looks like,

#!/bin/bash
JAVA=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin/java
CLJ_DIR=/opt/jars
CLOJURE=$CLJ_DIR/clojure.jar
CONTRIB=$CLJ_DIR/clojure-contrib.jar
JLINE=$CLJ_DIR/jline-0.9.94.jar
CP=$PWD:$CLOJURE:$JLINE:$CONTRIB

# Add extra jars as specified by `.clojure` file
if [ -f .clojure ]
then
  CP=$CP:`cat .clojure`
fi

if [ -z "$1" ]; then
  $JAVA -server -cp $CP \
      jline.ConsoleRunner clojure.lang.Repl
else
  scriptname=$1
  $JAVA -server -cp $CP clojure.main $scriptname -- $*
fi