I notice PHP compatibility conspicuously absent from so many libraries. Which is kind of amazing to me, since I "think" in PHP and MATLAB in a declarative and data-driven way. I do everything in sync blocking functional style and mostly just pipe data around. So I've found that the runners up (like Javascript, Python and Ruby) mostly just get in the way and force me to adopt their style. They're all roughly equivalent in power and expressivity, but nothing lets me go between a spreadsheet and the shell quite as easily as PHP.