(define (make-account balance password)
(define (withdraw amount)
(if (>= balance amount)
(begin (set! balance (- balance amount))
balance)
"Insufficient funds"))
(define (deposit amount)
(set! balance (+ balance amount))
balance)
(define (login-error amount) "Incorrect password")
(define (dispatch pass m)
(if (eq? pass password)
(cond ((eq? m 'withdraw) withdraw)
((eq? m 'deposit) deposit)
(else (error "Unknown request: MAKE-ACCOUNT"
m)))
login-error))
dispatch)
gosh> (define acc (make-account 100 'secret-password))
acc
gosh> ((acc 'secret-password 'withdraw) 50)
50
gosh> ((acc 'some-password 'deposit) 40)
"Incorrect password"
