~gdanix/telegram-bot-simple: Support backwards compatibility with older ghc.

da3e0b34ed10c92eb8694a2af7e6f722099ebcb0 — Alexander Vershilov 2 years ago 11b6c5e

Support backwards compatibility with older ghc.

For base<4.13 there is a method fail, that was is equal to
`error` call unless overriden. This commit reintroduces
method overriding so parser will not exit with exception on
the call to fail.

patch browse .tar.gz

1 files changed, 3 insertions(+), 0 deletions(-)

M src/Telegram/Bot/Simple/UpdateParser.hs

M src/Telegram/Bot/Simple/UpdateParser.hs => src/Telegram/Bot/Simple/UpdateParser.hs +3 -0

@@ 27,6 27,9 @@ instance Alternative UpdateParser where
 instance Monad UpdateParser where
   return = pure
   UpdateParser x >>= f = UpdateParser (\u -> x u >>= flip runUpdateParser u . f)
+#if !MIN_VERSION_base(4,13,0)
+  fail _ = empty
+#endif
 
 #if MIN_VERSION_base(4,13,0)
 instance MonadFail UpdateParser where