Some lisps let you use . to place procedures infix. IIRC racket allows you to write (x . < . 5), and some schemes have curly infix (a srfi) where {x < 5} gets

Some lisps let you use . to place procedures infix. IIRC racket allows you to write (x . < . 5), and some schemes have curly infix (a srfi) where {x < 5} gets translated to (< x 5).