Not sure if that example helps. You can make any programming language hard to read without some basic formatting. The way I would write the sexpr would be: (

Not sure if that example helps. You can make any programming language hard to read without some basic formatting. The way I would write the sexpr would be: (impl (impl p (impl q r)) (impl (impl p q) (impl p r))) It's clear when each section begins and ends and doesn't require complex parsing rules.