[PATCH 05/13] gnu: Add ghc-dlist.

[Siniša Biđin]

* gnu/packages/haskell.scm (ghc-dlist): New variable.
---
 gnu/packages/haskell.scm | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/gnu/packages/haskell.scm b/gnu/packages/haskell.scm
index 8c05c47..2da5f7f 100644
--- a/gnu/packages/haskell.scm
+++ b/gnu/packages/haskell.scm
@@ -357,6 +357,29 @@ package.")
   package.")
     (license bsd-3)))
 
+(define-public ghc-dlist
+  (package
+    (name "ghc-dlist")
+    (version "0.7.1.1")
+    (source
+      (origin
+        (method url-fetch)
+        (uri (string-append
+              "http://hackage.haskell.org/package/dlist/dlist-";
+              version
+              ".tar.gz"))
+        (sha256
+          (base32 "1zayvxvkan2s2ixajdr3f5rn1gzhprzv6cww4cbpwjhzw0l7zc08"))))
+    (arguments `(#:tests? #f))
+    (build-system haskell-build-system)
+    (home-page "https://github.com/spl/dlist";)
+    (synopsis "Difference lists")
+    (description
+      "Difference lists are a list-like type supporting O(1) append.  This is
+particularly useful for efficient logging and pretty printing (e.g. with the
+Writer monad), where list append quickly becomes too expensive.")
+    (license bsd-3)))
+
 (define-public ghc-mtl
   (package
     (name "ghc-mtl")
-- 
2.4.3