Subject: [bug#44174] [PATCH v2 07/15] gnu: Add ghc-only.

From: Carlo Holl <[email-masked]>
Date: Sat, 31 Oct 2020 19:02:28 -0700

* gnu/packages/haskell-xyz.scm (ghc-only): New variable.
---
 gnu/packages/haskell-xyz.scm | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/gnu/packages/haskell-xyz.scm b/gnu/packages/haskell-xyz.scm
index 93ae4b79b9..85ed28625a 100644
--- a/gnu/packages/haskell-xyz.scm
+++ b/gnu/packages/haskell-xyz.scm
@@ -8599,6 +8599,37 @@ old @code{time} library.  For new projects, the newer
 @uref{https://hackage.haskell.org/package/time, time library} is recommended.")
     (license license:bsd-3)))
 
+(define-public ghc-only
+  (package
+    (name "ghc-only")
+    (version "0.1")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append
+             "https://hackage.haskell.org/package/Only/Only-"
+             version
+             ".tar.gz"))
+       (sha256
+        (base32
+         "0rdj3a629fk2vp121jq8mf2smkblrz5w3cxhlsyx6my2x29s2ymb"))))
+    (build-system haskell-build-system)
+    (arguments
+     `(#:cabal-revision
+       ("1"
+        "1ahk7p34kmh041mz7lyc10nhcxgv2i4z8nvzxvqm2x34gslmsbzr")))
+    (home-page "https://hackage.haskell.org/package/Only")
+    (synopsis "The 1-tuple type or single-value \"collection\"")
+    (description "This package provides a canonical anonymous 1-tuple
+type missing from Haskell for attaching typeclass instances.
+
+NOTE: There is also the @url{https://hackage.haskell.org/package/OneTuple,
+OneTuple package} which by using a boxed @code{data}-type provides a 1-tuple
+type which has laziness properties which are more faithful to the ones of
+Haskell's native tuples; whereas the primary purpose of @code{Only} is to provide
+the traditionally so named type-wrapper for attaching typeclass instances.")
+    (license license:bsd-3)))
+
 (define-public ghc-opengl
   (package
     (name "ghc-opengl")
-- 
2.28.0