Genius at work

Over the years there has been a lot of propaganda claiming that Google both creates the only working environment in which double-super-genius types can function at peak effectiveness and then goes out of its way to hire only double-super-geniuses to work in it. How, then, does this happen:

We periodically receive updates to that list [of malevolent sites] and received one such update to release on the site this morning. Unfortunately (and here's the human error), the URL of '/' was mistakenly checked in as a value to the file and '/' expands to all URLs.

This sort of thing happens because of bad processes. It doesn't matter how smart folks are, if they work in a bad way, poor results will ensue.

Of course, I don't know exactly what occurred, but I'll bet you a pound that one lone double-super-genius is left to make changes to this file by themselves. 

Update: Jonathan Wolter raises some questions about testing such changes.

Self: the movie

My recent posting on Self provoked some interest on reddit and one keen redditor found the old Self movie. I first learned about Self when one of the giant pulsing brains from Manchester university came down to a BCS meeting in London (When did the BCS stop doing things that interesting? Why?) and showed us this movie. Great days.

Dynamic vs static: once more with feeling

In what feels to me like a voyage through a time-warp to the beginnings of my programming career in the mid–90's, Jason Gorman has revived the old static vs dynamic typing debate. 

Oh, how it all comes flooding back: "strong[sic] typing is for weak minds", "static type systems catch the kind of bug that managers understand" etc. etc. etc.

Jason's concerns seem to have been raised by someting to do with this sort of thing (see the part on the var keyword) although he seems to muddle up a language having a dynamic type system with it being dynamic. These aspects are closely related, but are not quite the same (as that post explains reasonably well). It's picking nits of this variety that keeps us all in work. 

Anyway, I very much agree with Jason that this resurgence of interest in dynamicish, scripty lanaguages is driven largely by fashion, and that claims made about it should be closely examined. I'm not so sure about the rest of his argument. Not least because I'm not sure that what he complains about: 

Proponents of such languages cite the relative flexibility of dynamic typing compared to statically-typed languages like Java and C++. Type safety, they argue, can be achieved through unit testing.

is actually being said by anyone. Type safety through unit testing? Really? Maybe someone is, and I haven't seen it. I'd be interested to if anyone has a link.

Personally, I do tend towards dynamic languages and away form manifest static type systems. My preference away from manifest static typing is that (in the words of, IIRC Kent Back) they make me say things that I don't know are true. On the other hand I've been dabbling a bit with Haskell, which has a very strong, very expressive static type system and offers the promise (through type inferencing) to not require all those pesky declarations. That has been both educational and fun. Unfortunately, as Nat pointed out in another context, that lovely promise might not be delivered upon:

[in Haskell] If you don't write explicit type constraints you can end up with a type inference error somewhere in your code. Where? The only way to find out is to incrementally add explicit type constraints (using binary chop, for example) to narrow down where the error is. It's not much different, and no easier, than using printf for debugging C code. 

If this is the best case of static typing, then we have a problem.

Meanwhile, let's consider the distinction between systems programming and application programming. Try googling around the various attempts to nail down that distinction. I don't find any of them terribly satisfactory. For me, the crucial distinction is that the system programmer must allow for any possibly use of their code, whereas an application programmer does not.

This means that in systems land a function declared like f :: int -> int must, unles very carefully specified otherwise, be known to do the right thing at every element of the whole of the cartesian product of the int type with itself. But in application land we might, for example, know that those ints are really the numbers of the days in the week, so we only really need the function to do the right thing over {0,1,2,3,4,5,6}² Demonstrating those two different kinds of correctness require different techniques, I think.

Of course, using int when you mean {0,1,2,3,4,5,6} is a smell. And here is the deodorant.

I want to join these two things up. I want to make a connection between the kind of correctness that systems code needs to have and the way that static typing is might help us with that versus the kind of correctness that application code needs to have and the way that unit testing might help us with that. But I'm not there yet. Watch this space.

Self

So, Self continues to be developed and has a very nice new site, here. Self is like Smalltalk "only more so". 

These days Self runs like a dream (and blindingly fast) on the Mac. Back in the day Self would only run on Sparc hardware, so I bought a Sun workstation for the express purpose of being able to play with Self. A wise investment. If a point of view is worth 80 IQ points then learning Self is a much better bet than all that brain training and smart drinks. 

I you want to understand to powerful (and fun and (partly, therefore) enticing) a system can be if you trust your users to manipulate objects directly, take a look at Self. If you want to understand just how far the notion of Integrating and Development Environment can be pushed (and how much fun that turns out to be) take a look at Self. If you want to understand why some folks consider Javascript to be such a huge missed opportunity, take a look at Self.