For Lispers: How accurate is this portrait of Lisp?

Being primarily a microsoft developer, I'm probably in the minority here. My coworker and I have been talking about branching out and learning completely different languages to stay fresh and learn some different views.

It took me 3 read throughs of this article to begin to get a sense of what makes people rave about LISP. I've also read Chapter 2 of PG's book. From what I can see, I like.

I'm not saying I'm a convert (yet!) but I absolutely plan on reading Paul's book and working through the examples and excercises there.

In the meantime, is the article a good way to think about Lisp?

Oddly enough, I can't tell. It seems to be a portrait expressed in terms of the broken reinventions of the Lisp wheel that currently occupy the median programmer's head. Sort of like describing a car as a "horseless carriage." But since I don't know those reinventions well, I can't say if this is an accurate portrait.

For example, someone recently told me that in Python you can't have conditionals within math expressions. E.g. you can say the equiv of

(if foo (+ x 1) (+ x 2))

but not

(+ x (if foo 1 2))

To me this just seems gratuitously restrictive. But I suppose it would at least be an accurate, if rather long, description of Lisp to teach people Python, and then say e.g. "Ok, now imagine if you could also just put any expression anywhere." Plus a few other things, of course...

"For example, someone recently told me that in Python you can't have conditionals within math expressions."

You can, but until Python 2.5 you needed to use a somewhat opaque idiom:

x + (foo and 1 or 2)

This works because the short-circuiting boolean operators return their second operand. So if foo is true, it'll evaluate 1, find that it's true, and return 1. If foo is false, it short-circuits over the 1, evaluates the 2, finds that that is a true value, and so returns 2. It's not intuitive at all, but most serious Pythonistas are familiar with it.

I agree that this is gratuitously restrictive, and evidently the Python developers did too. As of Python 2.5, you can do this:

x + (1 if foo else 2)

It's a shame that it took so long for them to add it, though.

The article is too long and not that well written. The biggest problem is that, however good the writer they are never going to be able to communicate the power of lisp in prose. It's upto the audience to see it. For those who know lisp, they already know. For those who don't it's like coming in contact with something alien and you can't tell if it solves any problem at all. It's almost as if ones' come in contact with a cult.

Though lisp provides a lot of syntactic flexibility. The beauty of lisp is in giving the programmer confidence that you can create a prototype extremely quickly and then optimize it when needed.

I find the hardest thing in the world is getting started. Once I start its never as hard as I thought it was going to be. In a nutshell, Lisp helps me get started and then lets me get the code ready for prime time.

If you are a web developer, I'd say spend a weekend trying out UCW, write a reddit clone in it. Then try to write it in python. It'll be obvious what lisp has to offer.

I'd start by reading SICP by Sussman and Abelson. Their lectures are available in video. I had a profound experience at the end of lecture 2b where they explain how car, cdr and cons are defined, thus explaining that in lisp, code is data.

The above comes with a warning... Lisp is truely the red pill. Once you've figured it out, you'll find it physically impossible to code in any other language.

I've never been afraid of the red pill. If it'll improve my ability to be effective, I'll gladly take it. :)

Without knowing much about Lisp, it seems that trying to describe it is like to trying to tell someone about Buddhism, or Jazz. Talking about it is just not the same thing as "getting it".

Thanks for your thoughts vikram, If I do become a convert I'll be sure to make a special post to news.yc :)