Clojure Made Simple

I want to thank everybody for coming.
The title of this talk is Clojure, Made Simple.

On the brochure, they left out the comma.
So it's not "Clojure made simple"

In other words, a tutorial on Clojure,
or an easy explanation of Clojure.

It's not actually a comprehensive explanation of Clojure at all.
But I'll look at a slice of what Clojure's about.

And a way of thinking about why you might want to use it.

So, I am the person who made Clojure.
I currently work on a database called Datomic,

which is kind of a functional database. It was written in Clojure, it runs on JVM architecture.

I'm a co-founder of Cognitect, which builds Datomic
and sponsors the development

and stewardship of Clojure.
But the main point I wanted to make about myself

to this audience was because in this talk I might
seem somewhat skeptical of Java and

object-oriented programming, is that I've done and absolute ton of that.

That's what I did for two decades before I said, 'if I still
want to be a programmer, I don't want to do it

this way anymore.'
So I know exactly how apps are built using Java

and C++ and C# because that's what I used to do.

That doesn't mean that what I think about them is correct,
but that's my experience.

But I'm wondering about you.
How many people program in Java here?

How many people are happy about that?
How many people are actively unhappy about that?

I'm looking for alternatives.
[laughter]

Okay, great. How many people have tried Clojure at all?

Ok, great. How many people have never heard of Clojure and are in the wrong room?

[laughter]

How many people have tried Clojure and are trying to get to use it at work, but not yet? A few.

Maybe this talk will give you some ways of talking about Clojure's value proposition that could help you.

How many people actively use Clojure?
and somehow are accidentally at JavaOne?

[laughter]
Okay, and the rest couldn't get into Brian Goetz's talk.

I shouldn't even mention that Brian Goetz has a talk
right now, because we're going to have people

filing out. Or maybe you're just tired of
Brian Goetz talking about immutability.

In which case, you're definitely in the wrong room.
[laughter]

No, I like him. Brian's a good friend. And his talks are great.
So I appreciate your being in this one.

So, there were very few people who had never
heard of Clojure. So I'm not going to

spend a lot of time on it.
Oh, I had one more question:

How many people have talk, "Simple Made Easy?"
How many people have not?

Okay, a few. So, I may spend a minute describing what
I mean when I say 'simple.'

Clojure is a programming language
that runs on the JVM and JavaScript.

And a substantial subset of Clojure runs on JavaScript.
So it's a programming language with which

you can target both.
But originally it only targeted the JVM and the CLR.

There's still a port to the CLR that's maintained,
but it does not see wide use.

I released it first in 2007. It's had surprising adoption.
Especially from my perspective since then,

given its characteristics. Because it's a lisp,
it's functional, it's data-oriented,

and it has a lot of things that make it seem
not like the kind of language that would succeed.

And this talk will really be about the data-orientation of Clojure.

So, a lot of the best programmers, and the most productive programmers I know are writing everything in blank

and swearing by it, and then just producing ridiculously sophisticated things in a very short time.

And that programmer productivity matters.
So Adrian Cockcroft was Cloud Architect at Netflix.

Now he's at Battery Ventures.
How many people think Java goes in the blank?

Okay. So we know, we know this.
There's something about Java that makes it

not suitable for this blank.