Archive for November, 2010

Moving Right Along

November 2, 2010

Of the six goals in my last post, four of them now work well. Here’s the latest PDF my code has produced. I’ve added three new tunes to it: another of my tunes, “Tali Foster’s”, a quick snippet from our ceili band’s notes from a few years back, and a double from the repertoire of Rufus Guinchard, “Sydney Pittman’s”. Together they demonstrate time signatures (6/8 and a single bar of 9/8), key changes, broken rhythms, and of course more than one tune on a page. (Note that 1st and 2nd endings are still unimplemented, and look very wrong in “Tali Foster’s”.)

I have to say that this PDF really impressed me with Lilypond’s output. It’s hard to put my finger on it, but something about having all four tunes together like that on the page looks really good, IMO. I’m getting excited about the prospect of being able to produce entire books of tunes with this tool.

In terms of Perl 6, this last nine days of work has been very straightforward. I did whine enough about the undeclared variable error message bug to convince pmichaud++ to fix it. I’d worried a lot about nested levels of Contexts — the key, time signature, etc — but I realized as I looked at it there are no nested levels, all changes affect the rest of the piece (until there is another change). I refactored to change several of the subs into methods, and made the context an attribute of their class. I’ve set things up so that Context objects are read-only, and you just create a new one when you need to change the context of the tune. So far this seems to work well.

I guess at this point I really need to implement 1st and 2nd endings, and then push on by throwing more tunes at it to see where they don’t work.

Update: Just in case you wanted to see what “Tali Foster’s” was supposed to look like with proper repeats, here’s the latest PDF. That is to say, first and second endings now work, at least in this one case. I’ve also realized that while key signatures work at the moment, accidentals don’t properly modify the key signature until the end of the bar — so that’s another thing that needs doing.