[Fencommits] fenfire-hs: turtle serialization escaping

[Benja Fallenstein]

Wed Mar 14 20:17:28 EET 2007  Benja Fallenstein <benja.fallenstein at gmail.com>
  * turtle serialization escaping
diff -rN -u old-fenfire-hs-1/Fenfire/RDF.hs new-fenfire-hs-1/Fenfire/RDF.hs
--- old-fenfire-hs-1/Fenfire/RDF.hs	2007-03-14 20:17:49.000000000 +0200
+++ new-fenfire-hs-1/Fenfire/RDF.hs	2007-03-14 20:17:49.000000000 +0200
@@ -28,6 +28,7 @@
 import Data.Map (Map)
 import qualified Data.Map as Map
 import Data.Maybe (fromMaybe, isJust)
+import qualified Numeric
 import Data.Set (Set)
 import qualified Data.Set as Set
 
@@ -118,11 +119,24 @@
     f ((short, long):xs) | take (length long) uri == long =
                                short ++ ":" ++ drop (length long) uri
                          | otherwise = f xs
-    f [] = "<" ++ uri ++ ">"
+    f [] = "<" ++ turtle_escaped '>' uri ++ ">"
 showNode _  (BNode graph id') = "bnode[" ++ id' ++ " @ " ++ graph ++ "]"
-showNode _  (Literal lit Plain) = show lit
-showNode _  (Literal lit (Lang lang)) = show lit ++ "@" ++ lang
-showNode _  (Literal lit (Type type')) = show lit ++ "^^<" ++ type' ++ ">"
+showNode ns (Literal lit tag) = "\"" ++ turtle_escaped '"' lit ++ "\"" ++
+    case tag of Plain -> ""; Lang lang  -> "@" ++ lang;
+                             Type type' -> "^^" ++ showNode ns (IRI type')
+
+turtle_escaped :: Char -> String -> String
+turtle_escaped _        [] = []
+turtle_escaped c ('\\':xs) = '\\':'\\':turtle_escaped c xs
+turtle_escaped c    (x:xs) | c == x 
+                           = '\\':   c:turtle_escaped c xs
+turtle_escaped c ('\n':xs) = '\\': 'n':turtle_escaped c xs
+turtle_escaped c ('\r':xs) = '\\': 'r':turtle_escaped c xs
+turtle_escaped c ('\t':xs) = '\\': 't':turtle_escaped c xs
+turtle_escaped c    (x:xs) | i <- fromEnum x, i < 0x20 || i == 0x5C 
+                           = '\\':'u':((if i<16 then ('0':) else id) $
+                                       Numeric.showHex i (turtle_escaped c xs))
+turtle_escaped c (   x:xs) =         x:turtle_escaped c xs
 
 subject :: Triple -> Node
 subject (s,_,_) = s