t3x.org / sketchy / library / modulo.html
SketchyLISP
Reference
  Copyright (C) 2006
Nils M Holm

modulo

Conformance: R5RS

Purpose: Compute the modulo of two numbers.

Arguments:
A - number (dividend)
B - number (divisor)

Implementation:

(define (modulo a b)
  (let ((rem (remainder a b)))
    (cond ((eq? (negative? a) (negative? b))
        rem)
      (#t (+ b rem)))))

Example:

(modulo 123 -23) 
=> -15

See also:
digits, remainder, quotient, divide, +, -, *.