Types are theorems; programs are proofs
[ Summary: I gave a talk Monday night on the Curry-Howard isomorphism; my talk slides are online. ]I sent several proposals to !!con, a conference of ten-minute talks. One of my proposals was to...
View ArticleGuess what this does
Here's a Perl quiz that I confidently predict nobody will get right. Without trying it first, what does the following program print? perl -le 'print(two + two == five ? "true" : "false")' (I will...
View ArticleGuess what this does (solution)
A few weeks ago I asked people to predict, without trying it first, what this would print: perl -le 'print(two + two == five ? "true" : "false")' (If you haven't seen this yet, I recommend that you...
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On uninhabited types and inconsistent logics
Earlier this week I gave a talk about the Curry-Howard isomorphism. Talks never go quite the way you expect. The biggest sticking point was my assertion that there is no function with the type a → b. I...
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Similarity analysis of quilt blocks
As I've discussed elsewhere, I once wrote a program to enumerate all the possible quilt blocks of a certain type. The quilt blocks in question are, in quilt jargon, sixteen-patch half-square triangles....
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When do n and 2n have the same digits?
[This article was published last month on the math.stackexchange blog, which seems to have died young, despite many earnest-sounding promises beforehand from people who claimed they would contribute...
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