15/40: gnu: Add ghc-transformers.

[Leo Famulari]

lfam pushed a commit to branch master
in repository guix.

commit 54c37341d1720c5cdd3772e729a419f2f46b6fb2
Author: ng0 <address@hidden>
Date:   Sun Sep 18 16:09:54 2016 +0000

    gnu: Add ghc-transformers.
    
    * gnu/packages/haskell.scm (ghc-transformers): New variable.
    
    Signed-off-by: Leo Famulari <address@hidden>
---
 gnu/packages/haskell.scm |   29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/gnu/packages/haskell.scm b/gnu/packages/haskell.scm
index 861f594..9205e95 100644
--- a/gnu/packages/haskell.scm
+++ b/gnu/packages/haskell.scm
@@ -6751,4 +6751,33 @@ preserved.  It also provides features for random access 
to archive content using
 an index.")
     (license license:bsd-3)))
 
+(define-public ghc-transformers
+  (package
+    (name "ghc-transformers")
+    (version "0.5.2.0")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append
+             "https://hackage.haskell.org/package/transformers/transformers-";
+             version ".tar.gz"))
+       (sha256
+        (base32
+         "1qkhi8ssf8c4jnmrw9dzym3igqbzq7h48iisaykdfzdsm09qfh3c"))))
+    (build-system haskell-build-system)
+    (home-page "http://hackage.haskell.org/package/transformers";)
+    (synopsis "Concrete functor and monad transformers")
+    (description
+     "A portable library of functor and monad transformers, inspired by the 
paper
+'Functional Programming with Overloading and Higher-Order Polymorphism',
+by Mark P Jones.  This package contains the monad transformer class and IO 
monad class,
+concrete functor and monad transformers, each with associated operations and 
functions
+to lift operations associated with other transformers.  The package can be 
used on
+its own in portable Haskell code, in which case operations need to be manually 
lifted
+through transformer stacks.  Alternatively, it can be used with the
+non-portable monad classes in the @code{mtl} or @code{monads-tf} packages,
+which automatically lift operations introduced by monad transformers through
+other transformers.")
+    (license license:bsd-3)))
+
 ;;; haskell.scm ends here