I had a nutty professor in college. He hooked me on scripting languages -- his favorite was gawk. He would write absolutely everything in gawk. Need a data structure? Use an associative array, it is the Gawk Way. Need code reuse? Cheaper to delete and start over. He was brilliant, I learned a lot from him, and I would not let him near my code if my life depended on it.
Lisp has always struck me as a "nutty professor" sort of language. I hear it is wonderful and pure and that if you truly grok it you see the Hand of God Himself in its awesome majesty staring out from within your code. But while Lisp seems to be long on awe, it seems to be short on software I'd actually want to use.
No one has ever claimed to have had a religious experience from reading PHP code (and if they did, I would suggest dousing them with holy water from a safe distance). But PHP has Wordpress. "Lisp can do a blogging platform too! Better! Stronger! Faster! We can do it, we have the technology!" Yes, Lisp can... but Lisp doesn't. (And if it did, I have a disturbing premonition that the steps to build a piece of blogging software would start with "#1: You need a webserver. None of the existing ones are exactly right, but that is no problem, since making a web server is easy in Lisp. First we define a few simple macros...")
Now, if I were a Lisp developer POed at ignorant savages on the Internet suggesting my language was perhaps a bit ivory-towery, I'd probably spend my time writing software which was so good they'd be unable to ignore me.
Or as Guile http://www.gnu.org/software/guile/guile.html suggests, if you're going to add a scripting/extension language to a program, they have a way of growing in size and complexity; just use guile.
If the point is "that program would have been easier for someone who knows lisp to write in lisp" then the reply is "but I was the person who bothered to write it and preferred to spend time getting a usable program than learning lisp", and it says more about the not-real-world-friendly nature of Lisp than about a deep similarity seen amongst large programs.
If the point is "lisp is a language in which you could write it more quickly" that's either unhelpful sideline commentary or smug taunting, depending on the intent.
If the point is "you could learn lisp and rework your understanding of your program into a lispy style and rewrite it in less time than just writing it in a language you know" - if that's true then there should be a lot more lisp programs around than there appear to be, which kind of suggests it's not true or that there's a sticking point which the saying doesn't account for that is preventing it being tested.
>Posted by Bill Magnuson, Hal Abelson, and Mark Friedman
and
>Scheme expertise was readily available among our team
And smile and chuckle a bit, you need to stop what you are doing immediately, and go read/watch/learn the SICP stuff from MIT - if for no other reason then to learn some of history.
http://groups.csail.mit.edu/mac/users/hal/hal.html
I guess that would explain where they got the idea to use Scheme.