pc:scale   scheme

;; returns a scale type based on a given root
(define pc:scale
   (lambda (root type)
     (if (string? type) (set! type (string->symbol type)))
      (if (assoc type *pc:scales*)
          (let loop ((l (cdr (assoc type *pc:scales*)))
                     (current (modulo root 12))
                     (newlst '()))
             (if (null? l)
                 (reverse (cons current newlst))
                 (loop (cdr l) (modulo (+ current (car l)) 12) (cons current newlst))))
          (begin (log-info "Scale type not found." *pc:scales*) #f))))