Actually adding intervals. Very close to working

fd.scm

@@ -3,10 +3,25 @@
   (export
     infd domfd =fd =/=fd <=fd <fd
     plusfd timesfd distinctfd range)
-  (import (rnrs) (ck) (finite-domain))
+  (import (rnrs) (ck) (interval-domain))
 
 ;;; helpers
 
+(define list-sorted?
+  (lambda (pred ls)
+    (cond
+      ((or (null? ls) (null? (cdr ls))) #t)
+      ((pred (car ls) (cadr ls))
+       (list-sorted? pred (cdr ls)))
+      (else #f))))
+
+(define list-insert
+  (lambda (pred x ls)
+    (cond
+      ((null? ls) (cons x '()))
+      ((pred x (car ls)) (cons x ls))
+      (else (cons (car ls) (list-insert pred x (cdr ls)))))))
+
 (define pred_x
   (lambda (x)
     (lambda (oc)

fdtests.scm

@@ -28,18 +28,25 @@
 ;;       (<=fd c 5)))
 ;;  '((1 2 3)))
 
-(test-check "1^^"
+(test-check "0.0"
   (run* (x)
     (infd x '(1 2)))
   '(1 2))
 
-(test-check "1^"
+(test-check "0.1"
+  (run* (x)
+    (fresh (y)
+      (infd x y '(1 2))
+      (=fd x y)))
+  '(1 2))
+
+(test-check "1.0"
   (run* (x)
     (infd x '(1 2))
     (=/=fd x 1))
   `(2))
 
-(test-check "1"
+(test-check "1.1"
   (run* (q)
     (fresh (x)
       (infd x q '(1 2))

finite-domain.scm

@@ -22,21 +22,6 @@
 ;; of value-doms?, with no duplicates.
 (define make-dom (lambda (n*) n*))
 
-(define list-sorted?
-  (lambda (pred ls)
-    (cond
-      ((or (null? ls) (null? (cdr ls))) #t)
-      ((pred (car ls) (cadr ls))
-       (list-sorted? pred (cdr ls)))
-      (else #f))))
-
-(define list-insert
-  (lambda (pred x ls)
-    (cond
-      ((null? ls) (cons x '()))
-      ((pred x (car ls)) (cons x ls))
-      (else (cons (car ls) (list-insert pred x (cdr ls)))))))
-
 (define map-sum
   (lambda (f)
     (letrec