(and (pair? x)
(number? (car x)) (number? (cdr x))))
+(define-public (number-pair-list? x)
+ (and (list? x)
+ (every number-pair? x)))
+
(define-public (fraction? x)
(and (pair? x)
(index? (car x)) (index? (cdr x))))
+(define-public (rational-or-procedure? x)
+ (or
+ (and (rational? x) (exact? x))
+ (procedure? x)))
+
(define-public (number-or-grob? x)
(or (ly:grob? x) (number? x)))