Change `PluginAction` type to `Message -> String`

Have `PluginAction` functions take a Message type instead of a plain
string. This gives us access to additional fields on the message:
channel and nick.

sorbot.cabal:
Add `Message` to `exposed-modules` in order to be able to use it when
building.

Lib.hs:
Change our test message to be a `Message` data type to conform to the new
`PluginAction` interface.

Plugin.hs:
Use `Message` where appropriate. When calling `perform`, pass it a
`Message` instead of a `String`. This means we have to match the regex
within the plugin in order to get the match data. The benefit of that
change is that now we have access to the full message in the plugin if
we need it, not just the regex-filtered part.

GitHubCommit.hs:
Do a regex match against the Message text in order to get the SHA we
want from the message.

1 files changed, 7 insertions, 5 deletions

diff --git a/src/Plugin.hs b/src/Plugin.hs
index 84b4779..d6598ec 100644
--- a/src/Plugin.hs
+++ b/src/Plugin.hs
@@ -6,23 +6,25 @@ module Plugin
 
 import Text.Regex.TDFA
 
+import qualified Message as M
 import Plugin.Base
 import Plugin.GitHubCommit
 
 -- | Get the first plugin that matches the given message text.
-matchPlugin :: String -> Maybe Plugin
+matchPlugin :: M.Message -> Maybe Plugin
 matchPlugin message = firstPlugin $ matchPlugins message plugins
   where
     firstPlugin []     = Nothing
     firstPlugin (p:ps) = Just p
 
 -- | Filter the list of plugins to those that match the given message.
-matchPlugins :: String -> [Plugin] -> [Plugin]
-matchPlugins message plugins = [p | p <- plugins, message =~ matchRegex p]
+matchPlugins :: M.Message -> [Plugin] -> [Plugin]
+matchPlugins message plugins =
+    [p | p <- plugins, M.text message =~ matchRegex p]
 
 -- | Run the action belonging to the plugin, stored in its `perform` field.
-performPlugin :: Plugin -> String -> String
-performPlugin p message = perform p $ message =~ matchRegex p
+performPlugin :: Plugin -> M.Message -> String
+performPlugin p message = perform p $ message
 
 -- | The list of plugins to load
 plugins :: [Plugin]