(examples-for len
("nonzero" (len "foo-bar") 7) ("zero" (len "") 0) ("nil is zero" (len nil) 0) ("sym is nil" (len 'abc) nil) ("fn is nil" (len len) nil) ("number is nil" (len 234) nil) ("ignores backslash-escaped interpolation symbol" (len "hello \~world") 12) ("returns length of proper list" (len '(a b)) 2) ("counts last item of improper list" (len '(a b c . d)) 4) ("counts keys of empty hash" (len { }) 0) ("counts keys of hash" (len { a 11 b 22 c 23 d nil e { nested t counted nil } }) 5))