Add the "set width" command

This is mostly needed for embedding, since there doesn't seem to be
any practical (let alone portable) standard way to notify pancake of
emacs window size changes.

In pancake.el, width adjustment is now getting done automatically
whenever any other command gets issued.

1 files changed, 12 insertions, 0 deletions

diff --git a/Pancake/Command.hs b/Pancake/Command.hs
index c385dc2..5126146 100644
--- a/Pancake/Command.hs
+++ b/Pancake/Command.hs
@@ -60,6 +60,7 @@ data Command = Quit
              | ShowCurrent
              | Shortcut String String
              | ReloadConfig
+             | SetWidth (Maybe Int)
              deriving (Show, Eq)
 
 -- | Parses a user command.
@@ -141,6 +142,16 @@ shortcut m = do
       q <- manyTill anyChar eof
       pure $ Shortcut u q
 
+-- | A natural numbers parser.
+pNat :: Read i => Parser i
+pNat = read <$> many1 digit
+
+-- | 'SetWidth' command parser.
+setWidth :: Parser Command
+setWidth = string "set width"
+           *> (SetWidth <$> optionMaybe (spaces *> pNat))
+           <* eof
+
 -- | Command parser.
 command :: Config -> Parser Command
 command c =
@@ -152,5 +163,6 @@ command c =
           , saveRef (referenceDigits c) <?> "save ref"
           , saveCurrent <?> "save current"
           , save <?> "save"
+          , setWidth <?> "set width"
           , goTo <?> "follow uri"
           ])