In TextMate 2 you can make a snippet placeholder such as: 

${1|red,green,blue|} 

And when you land on that placeholder, a list box pops up which lists the specified entries: red, green and blue. Then you can select one of those entries using arrow up/down keys, and hit tab to select and move to the next placeholder.

GAMS is a widely used modelling language to write optimization model.

I wrote a plugin for syntax highlighting and compilation command.

I'm getting lots of beachballs while using ST2 (2.0.1 build 2217). It seems that over time those are getting more frequent. Usually it spins for 3-5 seconds, but rarely it persists for 30-60 seconds, at which point I usually lose patience and kill ST2. No "slow plugin" alert appears when this happens. I have no idea how to debug this further. Any ideas?