(define-module (d-)
  #:use-module (srfi srfi-1)
  #:export
  (~>
   ~>>
   if-not
   when-not
   partial
   argmin))

(define-syntax ~>
  (syntax-rules ()
    [(_ v) v]
    [(_ v (fn args ...) more ...) (~> (fn v args ...) more ...)]
    [(_ v fn more ...) (~> (fn v) more ...)]))

(define-syntax ~>>
  (syntax-rules ()
    [(_ v) v]
    [(_ v (fn args ...) more ...) (~> (fn args ... v) more ...)]
    [(_ v fn more ...) (~> (fn v) more ...)]))

(define-syntax-rule (if-not pred body ...)
  (if (not pred) body ...))

(define-syntax-rule (when-not pred body ...)
  (when (not pred) body ...))

(define (partial fn . args)
  (lambda x (apply fn (append args x))))

(define (argmin f . vals)
  (reduce (lambda (val min)
	    (if (< (f val) (f min))
		val
		min))
	  #f
	  vals))