18/39: gnu: Add ghc-contravariant-extras.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 4562c8c894b16dcea4875c4dea19565de9a4c34c
Author: rsiddharth <address@hidden>
Date:   Wed Oct 18 03:07:38 2017 +0000

    gnu: Add ghc-contravariant-extras.
    
    * gnu/packages/haskell.scm (ghc-contravariant-extras): New variable.
    
    Signed-off-by: Ludovic Courtès <address@hidden>
---
 gnu/packages/haskell.scm | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/gnu/packages/haskell.scm b/gnu/packages/haskell.scm
index 31edf24..23c2d31 100644
--- a/gnu/packages/haskell.scm
+++ b/gnu/packages/haskell.scm
@@ -9491,4 +9491,27 @@ generating functions similar to those in 
@code{Data.List} for tuples of
 statically known size.")
     (license license:bsd-3)))
 
+(define-public ghc-contravariant-extras
+  (package
+    (name "ghc-contravariant-extras")
+    (version "0.3.3.1")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://hackage.haskell.org/package/";
+                           "contravariant-extras-" version "/"
+                           "contravariant-extras-" version ".tar.gz"))
+       (sha256
+        (base32
+         "1mbrgjybdx8fjdck4ldwi8955w4qnmm0ql56zix7dyn0s7s9spgk"))))
+    (build-system haskell-build-system)
+    (inputs `(("ghc-tuple-th" ,ghc-tuple-th)
+              ("ghc-contravariant" ,ghc-contravariant)
+              ("ghc-base-prelude",ghc-base-prelude)))
+    (home-page "https://github.com/nikita-volkov/contravariant-extras";)
+    (synopsis "Extras for the @code{ghc-contravariant} Haskell package")
+    (description "This Haskell package provides extras for the
address@hidden package.")
+    (license license:expat)))
+
 ;;; haskell.scm ends here