This sort of rule language you can put in configs is often useful. They tend to eventually cause problems as logic that should have been implemented properly ge

This sort of rule language you can put in configs is often useful. They tend to eventually cause problems as logic that should have been implemented properly gets embedded in the mini language and the little rules get more and more complicated (or even auto-generated from a simpler specification), but they are invaluable while they do work. One thing that surprised me was the inclusion of map/reduce/cat. Allowing these operators can make runtime exponential in the size of the program. I feel like that is against the spirit of the language.