From 593c3fe600a5f5e90a6eea3a175f83d3319b4efe Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Mon, 9 Dec 2013 21:10:28 +0100
Subject: monads: Fix 'anym'.

* guix/monads.scm (anym): Fix successful case.
* tests/monads.scm ("anym"): New test.
---
 guix/monads.scm | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'guix')

diff --git a/guix/monads.scm b/guix/monads.scm
index b62fc28a55..f5c9e8e9c7 100644
--- a/guix/monads.scm
+++ b/guix/monads.scm
@@ -228,9 +228,10 @@ lifted in MONAD, for which PROC returns true."
         (()
          (return #f))
         ((head tail ...)
-         (mlet monad ((value head))
-           (or (and=> (proc value) return)
-               head
+         (mlet* monad ((value  head)
+                       (result -> (proc value)))
+           (if result
+               (return result)
                (loop tail))))))))
 
 (define-syntax listm
-- 
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