Subject: [PATCH 07/16] gnu: Add ghc-only.

From: Carlo Holl <[email-masked]>
Date: Fri, 23 Oct 2020 10:05:35 -0700

---
 gnu/packages/haskell-xyz.scm | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/gnu/packages/haskell-xyz.scm b/gnu/packages/haskell-xyz.scm
index f090f62b86..e831c12160 100644
--- a/gnu/packages/haskell-xyz.scm
+++ b/gnu/packages/haskell-xyz.scm
@@ -8610,6 +8610,39 @@ 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