I've got a problem: I've had an idea I want to write about, but it depends on two or three other ideas I wanted to write about but never got around to. So I'm going to write this post in a top-down, Wirthian fashion, stubbing out those other posts: maybe, if there's enough interest, I'll come back and write them properly and replace the stubs here ( Read more... )

Random thought: I'm sure people who actually know about this stuff will be able to tell me why it won't work, or, alternatively, cases where it's already been done.

Recall the problem with the naive Haskell mean program
mean xs = sum xs / length xs
which when asked to calculate the mean of [1 .. 1e9] allocates 8GB of RAM and brings the computer to a ( Read more... )

There was a recent mailing list post by Andrew Coppin (which received some discussion on programming.reddit) in which he bemoans the way that GHC, when presented with reasonable-looking code, can suddenly and mysteriously decide that it needs to allocate gigabytes of memory, slowing your system to a crawl for ages (I've had similar problems myself ( Read more... )

I know I'm very late to the LOL$thing party, but what the hell:

( Cut for size )

A comparison of the Haskell argmunger with its Arc equivalent (or even its Perl equivalent) should make something clear. It's been claimed that Haskell doesn't need macros, because most of the things that Lispers need macros for can be done in Haskell using lazy evaluation and so on. But the argmunger example makes it clear that there are things ( Read more... )

[The hope was that this post would come in three somewhat independent sections: one pure programming, in which we develop a small utility in Template Haskell; one largely mathematics, at the upper-level high school to beginning undergraduate level, wherein we describe another approach to constructing our utility; and one purely mathematical, more ( Read more... )

My post about design patterns and if-statements in Smalltalk yesterday got a very pleasing reaction, garnering some informative comments from knowledgeable people and making the front page of programming.reddit. I guess I should have checked my facts on Smalltalk semantics more carefully before clicking "Post" :-) One comment that particularly ( Read more... )

I observe to my astonishment that I've made the "Quotes of the Week" section of this week's Haskell Weekly News. Um, gosh.

Now if only I could work out if I've been quoted because dons agrees with me or wishes to hold me up to public ridicule :-)

I'm going to make what should be an uncontroversial statement: if you don't understand and use monads, you are at best a quarter of a Haskell programmer. A corollary of this is that, since using monad transformers is the only (or at least the approved) way to use two or more monads together, if you don't understand and use monad transformers you ( Read more... )

totherme kindly drew my attention to this blog post today. The author, Slava Akhmechet, tries to explain away that horrible feeling of unproductivity and frustration that I know so well from my attempts to use Haskell: his claim is that it's just that my expectations are miscalibrated from using imperative languages. A Haskell solution to a given problem, ( Read more... )