From 326490cf13949b176708d517de491daff88a77ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Sun, 18 Sep 2022 23:01:57 +0200
Subject: Add uniq to hnh/util.

---
 module/hnh/util.scm | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/module/hnh/util.scm b/module/hnh/util.scm
index d2c0dd5f..3a2621d1 100644
--- a/module/hnh/util.scm
+++ b/module/hnh/util.scm
@@ -55,6 +55,12 @@
            assq-ref-all
            assv-ref-all
 
+           uniqx
+           uniq
+           univ
+           uniqv
+           unique
+
            vector-last
 
            ->string
@@ -506,6 +512,19 @@
 (define (assv-ref-all alist key)  (ass%-ref-all alist key eqv?))
 
 
+(define (uniqx = lst)
+  (cond ((null? lst) lst)
+        ((null? (cdr lst)) lst)
+        ((and (pair? lst)
+              (= (car lst) (cadr lst)))
+         (uniqx = (cons (car lst) (cddr lst))))
+        (else (cons (car lst)
+                    (uniqx = (cdr lst))))))
+
+(define (uniq lst) (uniqx eq? lst))
+(define (univ lst) (uniqx eqv? lst))
+(define (unique lst) (uniqx equal? lst))
+
 
 
 (define (vector-last v)
-- 
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