(define string->symbol
(lambda (sym) (send sym 'sym)))
(define substring
(lambda (string to from) (send string (quote []) to from)))
(define null?
(lambda (expr) (= expr ())))
(define >
(lambda (x y) (send x '> y)))
(define <
(lambda (x y) (send x '< y)))
(define =
(lambda (x y) (send x '== y)))
(define not
(lambda (expr) (if expr #f #t)))
(define car
(lambda (lst) (send lst 'first)))
(define cdr
(lambda (lst) (send lst 'rest)))
;; and friends (define cadr
(lambda (lst) (car (cdr lst))))