Morton Fox's journal

Snow, 24-28°F. At noon, I went to [undisclosed company] in Wilmington for my second-round interview. This time, I met up with only two of the three people from the first interview. It was longer though. We talked of many things. Of ships and sealing wax, of cabbages and kings... and also software development.

When I was done with the interview, I noticed that it had started snowing. The roads weren't really bad yet, but I saw a few accidents on the way back, including one overturned pickup truck. And that was before even an inch of snow had fallen! The truck didn't appear to have collided with any other vehicles but when I saw that, I decided it would be best to go directly home and stay home. In the evening, I went out to shovel the sidewalk and driveway. There was still less than an inch of snow on the pavement but I did that anyway and I was done in minutes.

With inclement weather comes a new software project. I actually started NuviGC a few days ago when I noticed that GSAK uses SQLite databases and wondered if perhaps I could write a script to query those databases directly and generate POI files for the Nuvi without going through GSAK. I'd been using this GSAK macro to generate POI files but it's a bit crufty and the author hasn't updated it in two years. The GSAK macro language is like Visual Basic with a lot of the good stuff missing, so I figured it would be better to reimplement it in Python and use that as a base on which to make my own improvements. And that's what I did. So far, I've added:

• Better linebreaks/formatting.
• Geocache attributes.
• Corrected coordinates in logs.
• Some workarounds for the Nuvi 295W.
• Substitutions for some HTML entities not recognized by POILoader.

I released TwitVim 0.5.4 yesterday, just a day ahead of Vim 7.3 final. I haven't written about TwitVim development in a few months. The last time I wrote in any detail was while I was in the middle of writing the OAuth code. From 0.5.0 to 0.5.4, there have been over 3 dozen revisions, mostly to complete the feature set with some bugfixes and documentation improvements thrown in the mix.

One issue I've struggled with in TwitVim 0.5.x is about requiring the user to use a Vim executable that has been compiled with one of the scripting interfaces. (Perl, Python, Ruby, or Tcl) The reason for this is I don't have a good implementation of the HMAC-SHA1 digest code in pure Vim script¹, so TwitVim has to sign OAuth requests by calling a HMAC-SHA1 module from one of those scripting languages. This is a terrible inconvenience; if it were not for this requirement, one would be able to run TwitVim in a precompiled Vim executable. Because of this requirement, a prospective TwitVim user now needs to be reasonably familiar with compilers and be able to build Vim from scratch. Furthermore, the required module isn't present by default in most Perl distributions other than ActivePerl, so the user has to fetch it from CPAN. Fortunately, the TwitVim user base (which seems to number about 3 at the moment :) ) appears to be quite good at those things. So far, those who contacted me with questions only needed a nudge in the right direction to get it working.

Another problem that's still unresolved at this time is Vim breaks some Tcl 8.5 modules. In particular, this bug prevents TwitVim from using Twitter SSL via the Tcl interface if Vim is compiled with Tcl 8.5. (TwitVim needs the "tls" package that I mentioned in my post to vim_dev. Tcl 8.4 is fine.) It was too late to address this issue in Vim 7.3, but I hope there'll be an official patch for this before Vim 7.4. (The unofficial patch is simply to hack out the redefinition of the "catch" command in if_tcl.c.)

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¹ There are Vim script modules for HMAC and SHA1 but these are very slow. The problem is Vim script does not have bitwise operators, so all the shifts, rotates, ANDs, ORs, and XORs have to be done using regular math operators and table lookups. It's really quite clever but I'd rather wait until the necessary enhancements are in Vim script before implementing HMAC-SHA1 in pure Vim script.