Add insert-between function

embddr/common.scm

@@ -15,6 +15,7 @@
           number->bits
           string-c-radix->number
           has-duplicates? find-duplicates
+          insert-between
 
           make-mux-selectors))
  (else
@@ -166,3 +167,20 @@
                        (bits-first-diff-msb abits obits)))
                    others))))))
      addrs)))
+
+;;; Insert object between list items
+;; (define (insert-between lst x)
+;;   (if (null? lst)
+;;       lst
+;;       (reverse
+;;        (cdr
+;;         (fold (lambda (item out)
+;;                 (cons* x item out))
+;;               '() lst)))))
+
+(define (insert-between lst x)
+  (if (or (null? lst)
+          (null? (cdr lst)))
+      lst
+      (cons* (car lst) x
+             (insert-between (cdr lst) x))))