diff --git a/skylighting-core/src/Skylighting/Parser.hs b/skylighting-core/src/Skylighting/Parser.hs
index c77f9724..e645d422 100644
--- a/skylighting-core/src/Skylighting/Parser.hs
+++ b/skylighting-core/src/Skylighting/Parser.hs
@@ -227,6 +227,7 @@ getParser casesensitive syntaxname itemdatas lists kwattr cattr el = do
   let str' = getAttrValue "String" el
   let insensitive = vBool (not casesensitive) $ getAttrValue "insensitive" el
   let includeAttrib = vBool False $ getAttrValue "includeAttrib" el
+  let weakDelim = Set.fromList $ T.unpack $ getAttrValue "weakDeliminator" el
   let lookahead = vBool False $ getAttrValue "lookAhead" el
   let firstNonSpace = vBool False $ getAttrValue "firstNonSpace" el
   let column' = getAttrValue "column" el
@@ -277,6 +278,7 @@ getParser casesensitive syntaxname itemdatas lists kwattr cattr el = do
                        then M.lookup cattr itemdatas
                        else M.lookup attribute itemdatas
                , rIncludeAttribute = includeAttrib
+               , rWeakDeliminators = weakDelim
                , rDynamic = dynamic
                , rCaseSensitive = not insensitive
                , rChildren = children
diff --git a/skylighting-core/src/Skylighting/Tokenizer.hs b/skylighting-core/src/Skylighting/Tokenizer.hs
index 50a8ddc0..f21376f0 100644
--- a/skylighting-core/src/Skylighting/Tokenizer.hs
+++ b/skylighting-core/src/Skylighting/Tokenizer.hs
@@ -334,7 +334,8 @@ tryRule rule inp = do
                                     stringDetect (rDynamic rule) (rCaseSensitive rule)
                                                  s inp
                 WordDetect s -> withAttr attr $
-                                    wordDetect (rCaseSensitive rule) s inp
+                                    wordDetect (rCaseSensitive rule)
+                                      (rWeakDeliminators rule) s inp
                 LineContinue -> withAttr attr $ lineContinue inp
                 DetectSpaces -> withAttr attr $ detectSpaces inp
                 DetectIdentifier -> withAttr attr $ detectIdentifier inp
@@ -380,9 +381,9 @@ withAttr tt p = do
      then return Nothing
      else return $ Just (tt, res)
 
-wordDetect :: Bool -> Text -> ByteString -> TokenizerM Text
-wordDetect caseSensitive s inp = do
-  wordBoundary inp
+wordDetect :: Bool -> Set.Set Char -> Text -> ByteString -> TokenizerM Text
+wordDetect caseSensitive weakDelims s inp = do
+  wordBoundary weakDelims inp
   t <- decodeBS $ UTF8.take (Text.length s) inp
   -- we assume here that the case fold will not change length,
   -- which is safe for ASCII keywords and the like...
@@ -395,7 +396,7 @@ wordDetect caseSensitive s inp = do
   let d = case UTF8.uncons rest of
                Nothing    -> '\n'
                Just (x,_) -> x
-  guard $ isWordBoundary c d
+  guard $ isWordBoundary weakDelims c d
   takeChars (Text.length t)
 
 stringDetect :: Bool -> Bool -> Text -> ByteString -> TokenizerM Text
@@ -549,7 +550,7 @@ regExpr :: Bool -> RE -> ByteString -> TokenizerM Text
 regExpr dynamic re inp = do
   -- return $! traceShowId $! (reStr, inp)
   let reStr = reString re
-  when (BS.take 2 reStr == "\\b") $ wordBoundary inp
+  when (BS.take 2 reStr == "\\b") $ wordBoundary mempty inp
   regex <- case compileRE re of
             Right r  -> return r
             Left e   -> throwError $
@@ -569,16 +570,18 @@ regExpr dynamic re inp = do
 toSlice :: ByteString -> (Int, Int) -> ByteString
 toSlice bs (off, len) = BS.take len $ BS.drop off bs
 
-wordBoundary :: ByteString -> TokenizerM ()
-wordBoundary inp = do
+wordBoundary :: Set.Set Char -> ByteString -> TokenizerM ()
+wordBoundary weakDelims inp = do
   case UTF8.uncons inp of
        Nothing -> return ()
        Just (d, _) -> do
          c <- gets prevChar
-         guard $ isWordBoundary c d
+         guard $ isWordBoundary weakDelims c d
 
-isWordBoundary :: Char -> Char -> Bool
-isWordBoundary c d = isWordChar c /= isWordChar d
+isWordBoundary :: Set.Set Char -> Char -> Char -> Bool
+isWordBoundary weakDelims c d =
+  (isWordChar c || c `Set.member` weakDelims) /=
+  (isWordChar d || d `Set.member` weakDelims)
 
 decodeBS :: ByteString -> TokenizerM Text
 decodeBS bs = case decodeUtf8' bs of
@@ -658,7 +661,7 @@ pCChar = do
 
 parseInt :: ByteString -> TokenizerM Text
 parseInt inp = do
-  wordBoundary inp
+  wordBoundary mempty inp
   case A.parseOnly (A.match (pHex <|> pOct <|> pDec)) inp of
        Left _      -> mzero
        Right (r,_) -> takeChars (BS.length r) -- assumes ascii
@@ -670,7 +673,7 @@ pDec = do
 
 parseOct :: ByteString -> TokenizerM Text
 parseOct inp = do
-  wordBoundary inp
+  wordBoundary mempty inp
   case A.parseOnly (A.match pHex) inp of
        Left _      -> mzero
        Right (r,_) -> takeChars (BS.length r) -- assumes ascii
@@ -685,7 +688,7 @@ pOct = do
 
 parseHex :: ByteString -> TokenizerM Text
 parseHex inp = do
-  wordBoundary inp
+  wordBoundary mempty inp
   case A.parseOnly (A.match pHex) inp of
        Left _      -> mzero
        Right (r,_) -> takeChars (BS.length r) -- assumes ascii
@@ -706,7 +709,7 @@ mbPlusMinus = () <$ A.satisfy (A.inClass "+-") <|> return ()
 
 parseFloat :: ByteString -> TokenizerM Text
 parseFloat inp = do
-  wordBoundary inp
+  wordBoundary mempty inp
   case A.parseOnly (A.match pFloat) inp of
        Left _      -> mzero
        Right (r,_) -> takeChars (BS.length r)  -- assumes all ascii
diff --git a/skylighting-core/src/Skylighting/Types.hs b/skylighting-core/src/Skylighting/Types.hs
index 9d20b473..47d056f7 100644
--- a/skylighting-core/src/Skylighting/Types.hs
+++ b/skylighting-core/src/Skylighting/Types.hs
@@ -130,6 +130,7 @@ data Rule = Rule{
     rMatcher          :: !Matcher
   , rAttribute        :: !TokenType
   , rIncludeAttribute :: !Bool
+  , rWeakDeliminators :: Set.Set Char
   , rDynamic          :: !Bool
   , rCaseSensitive    :: !Bool
   , rChildren         :: ![Rule]
diff --git a/skylighting-core/test/test-skylighting.hs b/skylighting-core/test/test-skylighting.hs
index a4f00c6e..b4923629 100644
--- a/skylighting-core/test/test-skylighting.hs
+++ b/skylighting-core/test/test-skylighting.hs
@@ -195,6 +195,16 @@ main = do
              @=? tokenize defConfig bash
                      "f() {\n    echo > f\n}\n"
 
+      , testCase "C floating-point literal (#174)" $ Right
+          [ [ ( DataTypeTok , "double")
+            , ( NormalTok , " x " )
+            , ( OperatorTok , "=" )
+            , ( NormalTok , " " )
+            , ( FloatTok , "0.5")
+            , ( OperatorTok , ";" ) ] ]
+             @=? tokenize defConfig c
+                     "double x = 0.5;\n"
+
       ]
     ]