This is a pretty interesting article. But, I'm not sure how much of an advantage there is in correlating to musical notation, as more modern composers (e.g. Cage, Xenakis) were moving away from traditional music notation systems.|
Most of the people I know are using Max-type languages (Max/MSP, JMax, Pd) rather than non-graphical languages like CSound (APL2 falls in this category). Of course, the people I know are working in real-time, so Max's "process-oriented" view might be more suitable.
I really wonder how many people are still using text-oriented music languages. I know CSound is still popular, but that may have more to do with its "legacy" nature. I've seen Hudak's Haskore and MacCartney's Supercollider, but I'm not sure that they have the same level (depth ?) of penetration into the mindshare of composers.