pc:chord   scheme

;; returns a chord given a root and type
;; see *pc:chord-syms* for currently available types
;;
;; e.g. (pc:chord 0 '^7)  => '(0 4 7 11)
(define pc:chord
  (lambda (root type)
      (let ((chord (assoc type *pc:chord-syms*)))
         (if chord
             (let loop ((l (cdr chord))
                        (newlst '()))
                (if (null? l)
                    (reverse newlst)
                    (loop (cdr l) (cons (modulo (+ (car l) root) 12) newlst))))
             (begin (log-info "Chord type not found." type) #f)))))