diff --git a/Text/TeXMath/Parser.hs b/Text/TeXMath/Parser.hs
--- a/Text/TeXMath/Parser.hs
+++ b/Text/TeXMath/Parser.hs
@@ -167,10 +167,10 @@
 inEnvironment :: String
               -> GenParser Char st Exp
               -> GenParser Char st Exp
-inEnvironment envType p = try $ do
-  char '\\'
-  symbol "begin"
-  braces $ symbol envType >> optional (symbol "*")
+inEnvironment envType p = do
+  try $ do char '\\'
+           symbol "begin"
+           braces $ symbol envType >> optional (symbol "*")
   result <- p
   char '\\'
   symbol "end"
@@ -208,7 +208,7 @@
           liftM (ESymbol Ord . (:[])) (satisfy $ not . isAlphaNum)
 
 command :: GenParser Char st String
-command = try $ char '\\' >> liftM ('\\':) (identifier <|> count 1 anyChar)
+command = try $ char '\\' >> liftM ('\\':) (identifier <|> lexeme (count 1 anyChar))
 
 unaryOps :: [String]
 unaryOps = ["\\sqrt", "\\surd"]
@@ -353,6 +353,8 @@
              , ("\\lbrace", ESymbol Open "{")
              , ("\\rbrack", ESymbol Close "]")
              , ("\\rbrace", ESymbol Close "}")
+             , ("\\llbracket", ESymbol Open "\x27E6")
+             , ("\\rrbracket", ESymbol Close "\x230B")
              , ("\\langle", ESymbol Open "\x3009")
              , ("\\rangle", ESymbol Close "\x300A")
              , ("\\lfloor", ESymbol Open "\x230A")
diff --git a/testTeXMathML.hs b/testTeXMathML.hs
--- a/testTeXMathML.hs
+++ b/testTeXMathML.hs
@@ -3,6 +3,8 @@
 import Text.TeXMath
 import Text.XML.Light
 
+import System.IO
+
 inHtml :: Element -> Element
 inHtml x =
   add_attr (Attr (unqual "xmlns") "http://www.w3.org/1999/xhtml") $
@@ -17,5 +19,5 @@
 main = do
   inp <- getContents
   case (texMathToMathML DisplayBlock $! inp) of
-       Left err         -> putStrLn err
+       Left err         -> hPutStrLn stderr err
        Right v          -> putStr . ppTopElement . inHtml $ v
diff --git a/texmath.cabal b/texmath.cabal
--- a/texmath.cabal
+++ b/texmath.cabal
@@ -1,5 +1,5 @@
 Name:                texmath
-Version:             0.1.0.1
+Version:             0.1.0.2
 Cabal-version:       >= 1.2
 Build-type:          Simple
 Synopsis:            Conversion of LaTeX math formulas to MathML.