Add TextColored constructor to TextType.

[API change]

+ Support `\color` in TeX reader.
+ Support TextColored in TeX writer.
+ Support TextColored in Pandoc writer.

Other writers have been modified so they don't crash with TextColored,
but currently they just ignore it.

See #225.

src/Text/TeXMath/Readers/TeX.hs

@@ -679,9 +679,10 @@ styled c = do
 
 colored :: Text -> TP Exp
 colored "\\color" = do
-  _ <- inbraces -- skip the color
+  color <- T.pack <$> braces (many1 letter)
   -- in the future we might add color to the types or to the styles
-  texSymbol <|> inbraces <|> texChar
+  contents <- unGrouped <$> (texSymbol <|> inbraces <|> texChar)
+  return $ EStyled (TextColored color) contents
 colored _ = mzero
 
 -- note: sqrt can be unary, \sqrt{2}, or binary, \sqrt[3]{2}

src/Text/TeXMath/Shared.hs

@@ -79,6 +79,7 @@ getMMLType t = fromMaybe "normal" (fst <$> M.lookup t textTypesMap)
 
 -- | Maps TextType to corresponding LaTeX command
 getLaTeXTextCommand :: Env -> TextType -> T.Text
+getLaTeXTextCommand _ (TextColored color) = "\\color{" <> color <> "}"
 getLaTeXTextCommand e t =
   let textCmd = fromMaybe "\\mathrm"
                   (snd <$> M.lookup t textTypesMap) in

src/Text/TeXMath/Types.hs

@@ -117,6 +117,7 @@ data TextType = TextNormal
               | TextBoldScript
               | TextBoldFraktur
               | TextSansSerifItalic
+              | TextColored T.Text
               deriving (Show, Read, Eq, Ord, Data, Typeable)
 
 data FormType = FPrefix | FPostfix | FInfix deriving (Show, Ord, Eq)

src/Text/TeXMath/Writers/OMML.hs

@@ -49,6 +49,9 @@ writeOMML dt = container . concatMap (showExp [])
 mnode :: Node t => String -> t -> Element
 mnode s = node (QName s Nothing (Just "m"))
 
+wnode :: Node t => String -> t -> Element
+wnode s = node (QName s Nothing (Just "w"))
+
 -- Kept as String for Text.XML.Light
 mnodeA :: Node t => String -> String -> t -> Element
 mnodeA s v = add_attr (Attr (QName "val" Nothing (Just "m")) v) . mnode s
@@ -122,6 +125,7 @@ setProps tt =
        TextBoldFraktur   -> [sty "b", scr "fraktur"]
        TextSansSerifItalic -> [sty "i", scr "sans-serif"]
        TextSansSerifBoldItalic -> [sty "bi", scr "sans-serif"]
+       TextColored color -> []  -- TODO
    where sty x = mnodeA "sty" x ()
          scr x = mnodeA "scr" x ()
 

src/Text/TeXMath/Writers/Pandoc.hs

@@ -91,6 +91,8 @@ renderStr (Just tt) s =
        TextBoldFraktur   -> [Strong [Str $ toUnicode tt s]]
        TextSansSerifItalic -> [Emph [Str s]]
        TextSansSerifBoldItalic -> [Strong [Emph [Str s]]]
+       TextColored color ->
+         [Span ("",[],[("style","color: " <> color <> ";")]) [Str s]]
 
 expToInlines :: Maybe TextType -> Exp -> Maybe [Inline]
 expToInlines tt (ENumber s) = Just $ renderStr tt s

test/reader/tex/color.test

@@ -0,0 +1,5 @@
+<<< tex
+\color{blue}{x}
+
+>>> native
+[ EStyled (TextColored "blue") [ EIdentifier "x" ] ]

test/writer/tex/color.test

@@ -0,0 +1,5 @@
+<<< native
+[ EStyled (TextColored "blue") [ EIdentifier "x" ] ]
+
+>>> tex
+\color{blue}{x}