Seems to me this discussion is missing one of the main points of the original post: a massive plug for an unfairly under-appreciated book:<p><pre><code>  &#62; "Let Over Lambda" 
  &#62; (which is really quite scary to read - I can't say that I understand 
  &#62; 100% of it - maybe 60% and I am very happy with that level of 
  &#62; comprehension) -- you end up with an enormously powerful set of 
  &#62; programming tools unlike anything else out there.
</code></pre>
I really like this book too and recommend it.<p><a href="http://letoverlambda.com/index.cl/toc" rel="nofollow">http://letoverlambda.com/index.cl/toc</a>