From a0a7e5accc4dc050057ecd99a9c741a65bd7ec5f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Tue, 5 Mar 2019 21:26:34 +0100
Subject: Add date-add to srfi srfi-19 util.

---
 srfi/srfi-19/util.scm | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'srfi')

diff --git a/srfi/srfi-19/util.scm b/srfi/srfi-19/util.scm
index 777f39f2..a020ae55 100644
--- a/srfi/srfi-19/util.scm
+++ b/srfi/srfi-19/util.scm
@@ -5,7 +5,9 @@
   #:export (copy-date
             drop-time! drop-time
             localize-date
-            date-today?))
+            date-today?
+            seconds minutes hours days weeks 
+            date-add))
 
 (define (copy-date date)
   "Returns a copy of the given date structure"
@@ -53,3 +55,13 @@ transposed to the current timezone. Current timezone gotten from
           (1+ (day then)))
     (and (%date<=? now input-date)
          (%date<=? input-date then))))
+
+(define seconds  1)
+(define minutes 60)
+(define hours   (* 60 minutes))
+(define days    (* 24 hours))
+(define weeks   (* 7 days))
+
+(define (date-add date amount unit)
+  (time-utc->date (add-duration (date->time-utc date)
+                 (make-time time-duration 0 (* amount unit)))))
-- 
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