I don’t have as much time today to write a full post, so I’ll take the easy way out and give a smattering of links I’ve enjoyed recently.
Fabulous Adventures in Coding – Making the code read like the spec
Eric Lippert is probably my favourite computer science blogger (even narowly beating the mighty Joel Spolsky) as not only do his interests in language design and linguistics intersect quite nicely with mine but he manages explains very complex topics in incredibly clear and concise ways, and still have the odd humourous side comment. If you’re not a software engineer and don’t care about identifying cycles in type hierarchies then just read the following few paragraphs:
First off, what is this thing called the “reflexive and transitive closure”?
Consider a “relation” – a function that takes two things and returns a Boolean[1] that tells you whether the relation holds. A relation, call it ~>, is reflexive if X~>X is true for every X. It is symmetric if A~>B necessarily implies that B~>A. And it is transitive if A~>B and B~>C necessarily implies that A~>C.
For example, the relation “less than or equal to” on integers is reflexive: X≤X is true for all X. It is not symmetric: 1≤2 is true, but 2≤1 is false. And it is transitive: if A≤B and B≤C then it is necessarily true that A≤C.
The relation “is equal to” is reflexive, symmetric and transitive; a relation with all three properties is said to be an “equivalence relation” because it allows you to partition a set into mutually-exclusive “equivalence classes”.
The relation “is the parent of” on people is not reflexive: no one is their own parent. It is not symmetric: if A is the parent of B, then B is not the parent of A. And it is not transitive: if A is the parent of B and B is the parent of C, then A is not the parent of C. (Rather, A is the grandparent of C.)
It is possible to take a nontransitive relation like “is the parent of” and from it produce a transitive relation. Basically, we simply make up a new relation that is exactly the same as the parent relation, except that we enforce that it be transitive. This is the “is the ancestor of” relation: if A is the ancestor of B, and B is the ancestor of C, then A is necessarily the ancestor of C. The “ancestor” relation is said to be the transitive closure of the “parent” relation.
I think that’s about as clear and concise way to define closures over relations anyone can write. If you really want your brain to flip then read his series of articles on covariance and contra-variance – mind blowing. Or if you want a bit of lighter relief, read his rants
Sceince, Reason and Critical Thought – Skeptic Park
Since learning about the BCA v Singh case through the authoritative Jack of Kent’s blog I’ve become rather too obsessed with skepticism/liberlism – I haven’t changed my political thinking very much (maybe moved from just right of centre to just left) but these writers seem to speak the same language as me and argue things I generally agree with, so I’m happy to stand under their metaphorical collective banner. Crispian Jago’s blog is the light relief in the crowd – in one video he wagers that ‘if homeopathy works I’ll drink my own piss’ and then proceeds to prepare a homeopathic solution from said urine and drink the result. Genius.
In the above linked cartoon he turns well known skeptics into South Park characters. Have an explore around his site for more gems.
Charlie Brooker – Christmas is the season of awful adverts
An article from a real newspaper – the Grauniad Guardian. As is all too well known to anyone who knows me, I’m quite a fan of Mr. Brooker, and I think this stands as one of his best rants. Particularly the following:
Watching Marks and Spencer’s Christmas ad is like sitting through Children in Need. Joanna Lumley, Stephen Fry, Myleene Klass, Jennifer Saunders, Twiggy, James Nesbitt, Wallace and Gromit . . . it’s so chummy and cosy and thoroughly delighted by its own existence, I keep hoping it’ll suddenly cut to a shot of a deranged crystal meth user squatting on the cold stone floor of a disused garage, screaming about serpents while feverishly sawing their own hand off at the wrist.Instead it jokily tries to undercut itself by including a cameo from Philip Glenister, standing in a pub to prove what a bumptiously down-to-earth Mr Bloke he is. His job is to stand at the bar claiming that the best thing about Christmas is the sexy girl from the Marks and Sparks ads running around in her knickers. Then it cuts to the sexy girl from the Marks and Sparks ads running around in her knickers, as though this is somehow as iconic a Christmas image as Rudolph’s nose or the little baby Jesus. Listen here, M&S: few things in life are more pukesome and hollow than a self-mythologising advert – so next year do us all a favour and just shake a few sleighbells, flog us some pants, and then piss off back to your smug little shop and be quiet.
Classic.
Enemies of Reason – My parcel hell
Another rant to be finishing off with, this time from Anton Vowl (who’s catchphrase should really be ‘reading the grotty, seedy newspapers so you don’t have to.’) – an angry, angry man. For extra comic value try reading his diatribe on getting parcels delivered in the style of Christian Bale’s famous shouty-fest[2]:
You tried? Oh good for you. What do you want – a fucking round of applause? How about I whine to you about a series of unsuccessful ‘attempts’ to pay you the money I owe you?
Proper service should be resumed tomorrow.
Mark
Do you do any work?!