A mapping from data type symbols to sorting functions to be used in for loops. For each "built-in" data type there are two functions specified: the first is used for ascending sorts, the second for descending.
`((string . (,string<? ,string>?)) (char . (,char<? ,char>?)) (number . (,< ,>)) (boolean . (,(lambda (a b) (or (not a) b)) ,(lambda (a b) (or a (not b))))))