As ye blitz, so shall ye be blitzed

Taking advantage of the good weather to put in some bike time, I've noticed:

• the potholes are at least as bad as last year, if not worse
• people on the shared bike path by the canal:
  • seem to take things at a rather slow pace, which wouldn't be a problem except that they...
  • walk or cycle two or three abreast, blocking the path and making it impossible to overtake
  • aren't very good at judging velocity and tend think they have more time to get out of the way of approaching bikes than they actually do
  • tend to be a bit casual about cycling on the left
  • aren't terribly good about paying attention on the blind bends
  • seem to own dogs with death wishes
• that the hills are much steeper than last year
• I really need to eat more if I'm going to keep up this sort of level of activity

I was also extremely impressed by the guy who passed me on the Riverside Valley cycle path: I was churning along at respectable 25 and he fairly flashed past me, much as I usually zip past the weekend cyclists. It's nice to know I've got something to aim for!

Python, distutils and IBM XL compilers

This may have been fixed in later versions of Python — I've been using 2.6.6 — but I've noticed that the standard distutils don't seem to work properly when (a) the interpreter has been built using the the XL compilers; and (b) when the extension being built needs to be linked with the C++ compiler, e.g. in SciPy. When both these conditions are met, distutils generates an invalid command link that features both the C++ compiler as the linker (correct) and C compiler as the second argument (horribly incorrect), as this example from an existing problem ticket shows:

error: Command "xlC xlC -qlanglvl=extc89 ..." failed with exit status 252

Not being willing (or able) to build each component by hand, I came up with a rough and ready fix — the if block that follows the platform test for 'aix5' — for distutils.unixccompiler.link() that seems to work around the problem:

( Source code... )

It's a long way from perfect — the test shouldn't really be for AIX but something like self.compiler_cxx.startswith("xl") and the code should search through the list, rather than simply removing element 1 — but it's a reasonable first cut at a solution to a deeply annoying problem.