changed ByteString to String since it doesn't matter anyway for this mini editor

src/App/Fontifier.hs

@@ -17,7 +17,6 @@ import qualified Text.Regex.TDFA as Tdfa
 
 ---- Various ----
 import           Data.Array
-import qualified           Data.ByteString as BS
 import Data.String
 
 {---- Type Definitions ----}
@@ -33,7 +32,7 @@ fontMap :: [(AttrName, Vty.Attr)]
 fontMap = [ (attrName "assignment"  , fg Vty.blue)
           , (attrName "return"      , fg Vty.green)
           , (attrName "guard"       , fg Vty.yellow)
-          , (attrName "comment"     , fg Vty.green)
+          , (attrName "comment"     , fg Vty.magenta)
           , (attrName "string"      , fg Vty.green)
           , (attrName "err_braces"  , fg Vty.red) -- unbalanced braces
           , (attrName "err_string"  , fg Vty.red) -- unterminated strings
@@ -41,23 +40,41 @@ fontMap = [ (attrName "assignment"  , fg Vty.blue)
 
 -- calls the fontification functions
 -- and returns a list of attributes for text slices
+-- fontification functions must take an IsString
+-- (either a ByteString, Text or normal String) and
+-- return a [Fontification] list
 fontify :: String -> [Fontification]
-fontify s = concat [guards bs, returns bs, strings bs, comments bs]
-  where bs = fromString s
+fontify = concatApply [guards, returns, strings, comments]
 
-guards :: BS.ByteString -> [Fontification]
-guards = matchAttrAll "guard" "\\[.*:.*\\]"
 
-returns :: BS.ByteString -> [Fontification]
-returns = matchAttrAll "return" "\\^.*;"
+-- applies the function in order
+-- the fontification of the last function overrules
+-- all previous ones in case more than one matches,
+-- the last function has the highest precedence
+-- can be useful to make e.g. comments "stronger" than strings
+-- a string in a comment is then fontified as comment
+concatApply :: [(String -> [Fontification])] -> String -> [Fontification]
+concatApply [] _ = []
+concatApply (f:fs) s = (f $ fromString s) ++ concatApply fs s
 
-strings :: BS.ByteString -> [Fontification]
+-- the same as concatApply just that the first function
+-- in the list has the highest precedence
+concatRevply :: [(String -> [Fontification])] -> String -> [Fontification]
+concatRevply fs = concatApply (reverse fs)
+
+guards :: String -> [Fontification]
+guards = matchAttrAll "guard" "\\[.+:.+\\]"
+
+returns :: String -> [Fontification]
+returns = matchAttrAll "return" "\\^.+;"
+
+strings :: String -> [Fontification]
 strings = matchAttrAll "string" "\".*\""
             
-comments :: BS.ByteString -> [Fontification]
+comments :: String -> [Fontification]
 comments = matchAttrAll "comment" "%.*\n"
 
-matchAttrAll :: String -> String -> BS.ByteString -> [Fontification]
+matchAttrAll :: String -> String -> String -> [Fontification]
 matchAttrAll attribute regexString bs =
   let regex = Tdfa.makeRegex regexString :: Tdfa.Regex
   in matchToFT (attrName attribute) $ Tdfa.matchAll regex bs
@@ -73,5 +90,5 @@ matchToFT attrName matchArray = matchToFT' matchArray
               end = (fst match) + (snd match)
           in FT {ftStart = start, ftEnd = end, ftAttr = attrName} : matchToFT' ms
 
-mismatchedBrackets :: BS.ByteString -> [Fontification]
+mismatchedBrackets :: String -> [Fontification]
 mismatchedBrackets bs = []

src/App/Gui.hs

@@ -135,7 +135,7 @@ handleEvent st ev
           return  $  st & file  .~ f                                                     -- replaces old state
                         & hedit .~ EditWidget.editor Hedit drawHeditText Nothing content -- with new text/file
 
--- just don't ask what this does --- inserts a string, returns the state. end of story.
+-- inserts a string, returns the state
 insertString :: String -> HeditState -> HeditState
 insertString string st = st & hedit %~ insertString' string -- uses some fancy lense magic
   where insertString' [] e = e