From aee88dedea562c405d38eb4dc1a2164b52281600 Mon Sep 17 00:00:00 2001
From: John Kehayias <john.kehayias@protonmail.com>
Date: Fri, 24 Dec 2021 13:51:33 -0500
Subject: [PATCH 2/5] gnu: Add ghc-semirings.
* gnu/packages/haskell-xyz.scm (ghc-semirings): New variable.
---
gnu/packages/haskell-xyz.scm | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
@@ -11398,6 +11398,40 @@ (define-public ghc-semigroups-bootstrap
ghc-unordered-containers-bootstrap ghc-hashable-bootstrap))
(properties '((hidden? #t)))))
+(define-public ghc-semirings
+ (package
+ (name "ghc-semirings")
+ (version "0.6")
+ (source
+ (origin
+ (method url-fetch)
+ (uri (string-append
+ "https://hackage.haskell.org/package/semirings/semirings-"
+ version
+ ".tar.gz"))
+ (sha256
+ (base32 "16q535bvjl7395sqkx6zlw48y4fzr7irp44pcp7w9irpn4cncdcr"))))
+ (build-system haskell-build-system)
+ (inputs
+ (list ghc-base-compat-batteries ghc-hashable ghc-unordered-containers))
+ (arguments
+ `(#:cabal-revision
+ ("1" "1c06yhfa053sv3rfz0d72a33l5qb0xmj1b3hy2z7pzxrcay6g1yc")))
+ (home-page "https://github.com/chessai/semirings")
+ (synopsis "Two monoids as one, in holy haskimony")
+ (description
+ "Haskellers are usually familiar with monoids and semigroups. A monoid has an
+appending operation @code{<>} (or @code{mappend}), and an identity element,
+@code{mempty}. A semigroup has an appending @code{<>} operation, but does not
+require a @code{mempty} element. A Semiring has two appending operations,
+@code{plus} and @code{times}, and two respective identity elements,
+@code{zero} and @code{one}. More formally, a Semiring R is a set equipped
+with two binary relations @code{+} and @code{*}, such that: (R,+) is a
+commutative monoid with identity element 0, (R,*) is a monoid with identity
+element 1, (*) left and right distributes over addition, and . multiplication
+by @code{0} annihilates R.")
+ (license license:bsd-3)))
+
(define-public ghc-serialise
(package
(name "ghc-serialise")
--
2.34.1