T.P.Format: Monoid, Semigroup instance for ExtensionsConfig.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/Text/Pandoc/Format.hs b/src/Text/Pandoc/Format.hs
index afd483577..c2065afb1 100644
--- a/src/Text/Pandoc/Format.hs
+++ b/src/Text/Pandoc/Format.hs
@@ -81,6 +81,14 @@ getExtensionsConfig fmt = ExtensionsConfig
   , extsSupported = getAllExtensions fmt
   }
 
+instance Semigroup ExtensionsConfig where
+  ExtensionsConfig x1 y1 <> ExtensionsConfig x2 y2 =
+    ExtensionsConfig (x1 <> x2) (y1 <> y2)
+
+instance Monoid ExtensionsConfig where
+  mappend = (<>)
+  mempty = ExtensionsConfig mempty mempty
+
 -- | Apply the extension changes in the format spec to the extensions
 -- given in the format's extensions configuration. Throws an error in
 -- case of an unknown or unsupported extension.