# Trait

A trait/typeclass system for Scheme.

## Example

    (import trait)
    
    (define-record point x y)
    
    (define-trait Eq
      ;; fallback to equal? by default
      (same? equal?))

    (define-trait-impl (Eq number?)
      (same? =))
    
    (define-trait-impl (Eq symbol?)
      (same? eq?))
    
    (define-trait-impl (Eq point?)
      (same? (lambda (a b) (and (point? b)
                                (= (point-x a) (point-x b))
                                (= (point-y a) (point-y b))))))
    
    (display (list (same? 'a 'a)
                   (same? 1 1)
                   (same? 1 2)
                   (same? (list 1 2) (list 1 2))
                   (same? (cons 3 4) (cons 3 4))
                   (same? (make-point 1 2) (make-point 3 4))))