From fad27a5caa9a20f975c75bf86a1798be1411de48 Mon Sep 17 00:00:00 2001
From: Owen Shepherd <owen@owen.cafe>
Date: Sun, 26 Nov 2023 17:43:13 +0100
Subject: [PATCH] chore: Test with more GHC versions

---
 .github/workflows/haskell-ci.yml            | 34 +++++++++++++++++++--
 README.md                                   |  3 +-
 pandoc-builder-monadic.cabal                | 11 ++++++-
 src/Text/Pandoc/Builder/Monadic/Internal.hs |  6 ++++
 4 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index f80cdb6..1794915 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -43,6 +43,36 @@ jobs:
             compilerVersion: 9.2.8
             setup-method: ghcup
             allow-failure: false
+          - compiler: ghc-9.0.2
+            compilerKind: ghc
+            compilerVersion: 9.0.2
+            setup-method: ghcup
+            allow-failure: false
+          - compiler: ghc-8.10.7
+            compilerKind: ghc
+            compilerVersion: 8.10.7
+            setup-method: ghcup
+            allow-failure: false
+          - compiler: ghc-8.8.4
+            compilerKind: ghc
+            compilerVersion: 8.8.4
+            setup-method: hvr-ppa
+            allow-failure: false
+          - compiler: ghc-8.6.5
+            compilerKind: ghc
+            compilerVersion: 8.6.5
+            setup-method: hvr-ppa
+            allow-failure: false
+          - compiler: ghc-8.4.4
+            compilerKind: ghc
+            compilerVersion: 8.4.4
+            setup-method: hvr-ppa
+            allow-failure: false
+          - compiler: ghc-8.2.2
+            compilerKind: ghc
+            compilerVersion: 8.2.2
+            setup-method: hvr-ppa
+            allow-failure: false
           - compiler: ghc-8.0.2
             compilerKind: ghc
             compilerVersion: 8.0.2
@@ -174,8 +204,8 @@ jobs:
           touch cabal.project
           touch cabal.project.local
           echo "packages: ${PKGDIR_pandoc_builder_monadic}" >> cabal.project
-          if [ $((HCNUMVER >= 90200)) -ne 0 ] ; then echo "package pandoc-builder-monadic" >> cabal.project ; fi
-          if [ $((HCNUMVER >= 90200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "package pandoc-builder-monadic" >> cabal.project ; fi
+          if [ $((HCNUMVER >= 80200)) -ne 0 ] ; then echo "    ghc-options: -Werror=missing-methods" >> cabal.project ; fi
           cat >> cabal.project <<EOF
           EOF
           $HCPKG list --simple-output --names-only | perl -ne 'for (split /\s+/) { print "constraints: $_ installed\n" unless /^(pandoc-builder-monadic)$/; }' >> cabal.project.local
diff --git a/README.md b/README.md
index 2792a4d..0442f2a 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,6 @@
 # pandoc-builder-monadic
 
-
-[![CI status badge](https://img.shields.io/github/actions/workflow/status/414owen/pandoc-builder-monadic/haskell-ci.yml)](https://github.com/414owen/pandoc-builder-monadic/actions/workflows/haskell-ci.yml) [![Hackage version badge](https://img.shields.io/hackage/v/pandoc-builder-monadic)](https://hackage.haskell.org/package/pandoc-builder-monadic) [![license](https://img.shields.io/github/license/414owen/pandoc-builder-monadic)](https://github.com/414owen/pandoc-builder-monadic/blob/master/LICENSE)
+[![GHC version badge](https://img.shields.io/badge/ghc-%3E%3D8.0.2-blue?logo=haskell)](https://www.haskell.org/) [![CI status badge](https://img.shields.io/github/actions/workflow/status/414owen/pandoc-builder-monadic/haskell-ci.yml)](https://github.com/414owen/pandoc-builder-monadic/actions/workflows/haskell-ci.yml) [![Hackage version badge](https://img.shields.io/hackage/v/pandoc-builder-monadic)](https://hackage.haskell.org/package/pandoc-builder-monadic) [![license](https://img.shields.io/github/license/414owen/pandoc-builder-monadic)](https://github.com/414owen/pandoc-builder-monadic/blob/master/LICENSE)
 
 This library provides a monadic DSL for constructing Pandoc documents.
 
diff --git a/pandoc-builder-monadic.cabal b/pandoc-builder-monadic.cabal
index 7e06ab7..575d4e8 100644
--- a/pandoc-builder-monadic.cabal
+++ b/pandoc-builder-monadic.cabal
@@ -14,7 +14,16 @@ maintainer:      owen@owen.cafe
 category:        Text
 build-type:      Simple
 extra-source-files: README.md CHANGELOG.md
-tested-with:     GHC==9.6.2, GHC==9.4.5, GHC==9.2.8, GHC==8.0.2
+tested-with:        GHC==9.6.2
+                  , GHC==9.4.5
+                  , GHC==9.2.8
+                  , GHC==9.0.2
+                  , GHC==8.10.7
+                  , GHC==8.8.4
+                  , GHC==8.6.5
+                  , GHC==8.4.4
+                  , GHC==8.2.2
+                  , GHC==8.0.2
 
 common warnings
     ghc-options: -Wall -Wextra -Wunused-packages
diff --git a/src/Text/Pandoc/Builder/Monadic/Internal.hs b/src/Text/Pandoc/Builder/Monadic/Internal.hs
index 2f13a91..ca7bbdc 100644
--- a/src/Text/Pandoc/Builder/Monadic/Internal.hs
+++ b/src/Text/Pandoc/Builder/Monadic/Internal.hs
@@ -55,6 +55,12 @@ instance Semigroup (BuilderM el a) where
 
 instance Monoid a => Monoid (BuilderM el a) where
   mempty = Builder $ pure mempty
+#if !(MIN_VERSION_base(4,11,0))
+  mappend f g = do
+    a <- f
+    b <- g
+    pure (mappend a b)
+#endif
 
 instance B.ToMetaValue (Builder Inline) where
   toMetaValue = B.MetaInlines . runToList