User experience

[We open in a well-lit corporate conference room. A meeting has been running for a while. Lots has been accomplished but time is running out.]

[The door opens and a tall, tow-headed twenty-something guy in glasses walks in, carrying a Mac Air and a folder.]

Manager:

Oh, here he is. This is Richard. I asked him to join us today. Glad he could make it. He's got some great user experience ideas.

Richard:

Call me Dick.

Manager:

Dick's done a lot of seminal UX work for us.

Engineer:

Hey, aren't you the guy who's arguing we shouldn't have search in e-books?

Dick:

Absolutely. It's a lousy idea.

Engineer:

What?

Dick:

Books are the best UI ever created. They've been perfected over more than 500 years of development. We shouldn't mess with success.

Product manager:

Well, this is a new age. We should be allowed to ...

Dick:

Books have never had search. If we add search, we'll just confuse the user.

Product manager:

Oh, you're right. We don't want to do that.

Engineer:

But e-books aren't physical books. They're not words on paper. They're just bits, information.

Dick:

Our users don't know that.

Engineer:

Yes they do! They don't want simple books, they want the possibilities that electronic books can bring. Do you know about information theory? Have you even heard of Claude Shannon?

Dick:

Isn't he the chef at that new biodynamic tofu restaurant in North Beach?

Engineer:

Uhh, yeah, OK. But look, you're treating books as a metaphor for your user interface. That's as lame as using a trash can to throw away files and folders. We can do so much more!

Dick:

You misunderstand. Our goal is to make computers easier to use, not to make them more useful.

Product manager:

Wow, that's good.

Engineer:

Wow.

Manager:

Let's get back on track. Dick, you had some suggestions for us?

Dick:

Yeah. I was thinking about the work we did with the Notes iPhone app. Using a font that looked like a felt marker was a big help for users.

Engineer:

Seriously?

Dick:

Yes, it made users feel more comfortable about keeping notes on their phone. Having a font that looks like handwriting helps them forget there's a computer underneath.

Engineer:

I see....

Dick:

Yes, so... I was thinking for the Address Book app for Lion, we should change the look to be like a...

Manager:

Can you show us?

Dick:

Yeah, sure. I have a mock-up here.

[Opens laptop, turns it to face the room.]

Product manager:

An address book! That's fantastic. Look at the detail! Leather, seams at the corners, a visible spine. This is awesome!

Engineer:

It's just a book. It's a throwback. What are you doing? Why does it need to look like a physical address book?

Dick:

Because it is an address book!

Engineer:

No it's not, it's an app!

Dick:

It's a book.

Engineer:

You've made it one. This time it's not even a metaphor - it's literally a book. You're giving up on the possibility of doing more.

Dick:

As I said, users don't care about functionality. They want comfort and familiarity. An Address Book app that looks like an address book will be welcome. Soothing.

Engineer:

If they want a paper address book, they can buy one.

Dick:

Why would they do that if they have one on their desktop?

Engineer:

Can they at least change the appearance? Is there a setting somewhere?

Dick:

Oh, no. We know better than the user - otherwise why are we here? Settings are just confusing.

Engineer:

I ... I really don't understand what's going on.

Manager:

That's OK, you don't have to, but I'd like to give you the action item to build it. End of the quarter OK?

Engineer:

Uhhh, sure.

Manager.

Dick, do you have the requirements doc there?

Dick:

Right here.

[Pushes the folder across the desk.]

Engineer:

Can't you just mail it to me?

Dick:

It's right there.

Engineer:

I know, but... OK.

Manager:

That's a great start, Dick. What else do you have?

Dick:

Well, actually, maybe this is the time to announce that I'm moving on. Today is my last day here.

Manager, Product manager:

[Unison] Oh no!

Dick:

Yeah, sorry about that. I've had an amazing time here changing the world but it's tiem for me to seek new challenges.

Manager:

Do you have something in mind?

Dick:

Yes, I'm moving north. Microsoft has asked me to head a group there. They've got some amazing new ideas around paper clips.

FADE

Regular expressions in lexing and parsing

Comments extracted from a code review. I've been asked to disseminate them more widely.

I should say something about regular expressions in lexing and parsing. Regular expressions are hard to write, hard to write well, and can be expensive relative to other technologies. (Even when they are implemented correctly in N*M time, they have significant overheads, especially if they must capture the output.) Lexers, on the other hand, are fairly easy to write correctly (if not as compactly), and very easy to test. Consider finding alphanumeric identifiers. It's not too hard to write the regexp (something like "[a-ZA-Z_][a-ZA-Z_0-9]*"), but really not much harder to write as a simple loop. The performance of the loop, though, will be much higher and will involve much less code under the covers. A regular expression library is a big thing. Using one to parse identifiers is like using a Mack truck to go to the store for milk. And when we want to adjust our lexer to admit other character types, such as Unicode identifiers, and handle normalization, and so on, the hand-written loop can cope easily but the regexp approach will break down.

A similar argument applies to parsing. Using regular expressions to explore the parse state to find the way forward is expensive, overkill, and error-prone. Standard lexing and parsing techniques are so easy to write, so general, and so adaptable there's no reason to use regular expressions. They also result in much faster, safer, and compact implementations.

Another way to look at it is that lexers and parsing are matching statically-defined patterns, but regular expressions' strength is that they provide a way to express patterns dynamically. They're great in text editors and search tools, but when you know at compile time what all the things are you're looking for, regular expressions bring far more generality and flexibility than you need.

Finally, on the point about writing well. Regular expressions are, in my experience, widely misunderstood and abused. When I do code reviews involving regular expressions, I fix up a far higher fraction of the regular expressions in the code than I do regular statements. This is a sign of misuse: most programmers (no finger pointing here, just observing a generality) simply don't know what they are or how to use them correctly. Encouraging regular expressions as a panacea for all text processing problems is not only lazy and poor engineering, it also reinforces their use by people who shouldn't be using them at all.

So don't write lexers and parsers with regular expressions as the starting point. Your code will be faster, cleaner, and much easier to understand and to maintain.

Know your science

Except for the TV show "The Big Bang Theory", popular culture gets science wrong. We all know that.

But there's a way it tends to get science wrong that upsets me more than most. That is when it misuses the tools of science by willfully ignoring what science actually means.

One common example is celebrity equations, wherein some mathematical-looking expression mixes two or more celebrities together, as in (I'm making this one up and I'm not a cultural critic, let alone a comic, so please bear with me): Lady Gaga = (2*Madonna + Carrot Top)/3. Mathematically savvy readers will recognize that I normalized that equation. If you don't know what that means, you shouldn't be writing celebrity equations, because mathematical equations mean something, they're not just symbols. Like musical comedy based on bad notes, bogus mathematical equations are not funny, just lazy.

Some years ago I even wrote a letter to Entertainment Weekly when they had a long article full of egregious celebrity equations. To their credit, they published the letter and even mended their ways for a while. I quote the letter here:

According to EW math, the more buzz or intelligence you have, the less likely you are to be on the It List. That may be true, but I bet you didn't mean that. Your equation is art-directed nonsense. EW seems to think the joke is that the equations look cute: If Einstein is funny, his square root is hilarious...

In short, mathematics may look funny if you don't understand it but that doesn't make it funny if you misuse it in ignorance.

Another sort of abuse is comedy periodic tables: periodic tables of the vegetables, period table of the desserts, periodic table of the presidents, and on and on. There are zillions of them. I believe the vegetables one was the first widely distributed example.

What's wrong with them? Again, they miss the point about the one true periodic table, Mendeleev's periodic table of the elements. In fact, to put things with no structure into a periodic table not only misses the point of the periodic table, it misses the profound idea that some things have periods.

Mendeleev's table, by recognizing the periodic structure of the elements, predicted not only properties of the elements, but the very existence of undiscovered elements. It was a breakthrough.

The periodic table is not some artistic layout of letters, it's science at its very best, one of the great results of the 19th century and the birth of modern chemistry. It doesn't honor science to take, say, typefaces and put them in a funny-looking grid. That just mocks the idea that science can predict the way the world works.

Science is not arbitrary. Making arbitrary cultural artifacts by abusing scientific ideas is not just wrong, it's offensive. It cheapens science.

Another area of abuse is quantum mechanics, and a common victim is Heisenberg's uncertainty principle. Despite what some ill-informed academics would have you believe, Heisenberg's principle is not some general statment about weird shit happening in the world, it is a fantastically precise scientific statement about the limits of measurement of two simultaneous physical properties: position and momentum. It's not a metaphor!

What's really sad is that many of the commonest misuses of the terminology of quantum mechanics come from other areas of science and technology. For instance, there is a term in computer engineering called a Heisenbug, which refers to faults that are unpredictable, most often for bugs that go away when you examine them. It's a cute name but it isn't even a correct reference. The quantum mechanical property of things changing when you observe them is not the Heisenberg uncertainty principle, it's the observer effect. These two ideas are often confused but they are not the same. They're not even closely related.

The observer effect in quantum mechanics describes how the act of measuring a quantum system forces the system to cough up a measurable quantity, which triggers a "wave function collapse". Heisenberg's uncertainty principle says that the minimum product of the error in simultaneous measurement of a particle's position and momentum is Planck's constant divided by 4π, or as we write it in physics, ℏ/2. (By the way, that's an extremely small value.)

Not only are these very different ideas, neither of them has anything to do with computer bugs. The term Heisenbug is trendy but bogus and ignores some strange and beautiful ideas. It's no better informed than the square root of Einstein or the periodic table of the typefaces.

If you're going to use the terms of science to inform your world, please make a point to understand the science too. Your world will be richer for it.