added API for reading a list of tuples in the SG module

2 files changed, 32 insertions, 1 deletions

diff --git a/src/runtime/haskell-bind/PGF2/FFI.hs b/src/runtime/haskell-bind/PGF2/FFI.hs
index ee26214c7..fc658d83d 100644
--- a/src/runtime/haskell-bind/PGF2/FFI.hs
+++ b/src/runtime/haskell-bind/PGF2/FFI.hs
@@ -237,6 +237,9 @@ foreign import ccall "pgf/expr.h pgf_read_expr"
 foreign import ccall "pgf/expr.h pgf_read_expr_tuple"
   pgf_read_expr_tuple :: Ptr GuIn -> CInt -> Ptr PgfExpr -> Ptr GuPool -> Ptr GuExn -> IO CInt
 
+foreign import ccall "pgf/expr.h pgf_read_expr_matrix"
+  pgf_read_expr_matrix :: Ptr GuIn -> CInt -> Ptr GuPool -> Ptr GuExn -> IO (Ptr GuSeq)
+
 foreign import ccall "pgf/graphviz.h pgf_graphviz_abstract_tree"
   pgf_graphviz_abstract_tree :: Ptr PgfPGF -> PgfExpr -> Ptr GuOut -> Ptr GuExn -> IO ()
 
diff --git a/src/runtime/haskell-bind/SG.hsc b/src/runtime/haskell-bind/SG.hsc
index 5ee02b8b2..b6707f031 100644
--- a/src/runtime/haskell-bind/SG.hsc
+++ b/src/runtime/haskell-bind/SG.hsc
@@ -11,6 +11,7 @@ module SG( SG, openSG, closeSG
          , updateFtsIndex
          , queryLinearization
          , readTriple, showTriple
+         , readTriples
          , insertTriple, getTriple
          , queryTriple
          ) where
@@ -147,7 +148,7 @@ readTriple str =
     do exprPl <- gu_new_pool
        withGuPool $ \tmpPl ->
          withCString str $ \c_str ->
-           withTriple $ \triple -> do
+           withTriple $ \triple ->
              do guin <- gu_string_in c_str tmpPl
                 exn <- gu_new_exn tmpPl
                 ok <- pgf_read_expr_tuple guin 3 triple exprPl exn
@@ -176,6 +177,33 @@ showTriple (Expr expr1 _) (Expr expr2 _) (Expr expr3 _) =
          s <- gu_string_buf_freeze sb tmpPl
          peekCString s
 
+readTriples :: String -> Maybe [(Expr,Expr,Expr)]
+readTriples str =
+  unsafePerformIO $
+    do exprPl <- gu_new_pool
+       withGuPool $ \tmpPl ->
+         withCString str $ \c_str ->
+             do guin <- gu_string_in c_str tmpPl
+                exn <- gu_new_exn tmpPl
+                seq <- pgf_read_expr_matrix guin 3 exprPl exn
+                status <- gu_exn_is_raised exn
+                if (seq /= nullPtr && not status)
+                  then do exprFPl <- newForeignPtr gu_pool_finalizer exprPl
+                          count <- (#peek GuSeq, len) seq
+                          ts <- peekTriples exprFPl (fromIntegral (count :: CInt)) (seq `plusPtr` (#offset GuSeq, data))
+                          return (Just ts)
+                  else do gu_pool_free exprPl
+                          return Nothing
+  where
+    peekTriples exprFPl count triple
+      | count == 0 = return []
+      | otherwise  = do c_expr1 <- peekElemOff triple 0
+                        c_expr2 <- peekElemOff triple 1
+                        c_expr3 <- peekElemOff triple 2
+                        let t = (Expr c_expr1 exprFPl,Expr c_expr2 exprFPl,Expr c_expr3 exprFPl)
+                        ts <- peekTriples exprFPl (count-3) (triple `plusPtr` (3*sizeOf c_expr1))
+                        return (t:ts)
+
 insertTriple :: SG -> Expr -> Expr -> Expr -> IO SgId
 insertTriple (SG sg) (Expr expr1 _) (Expr expr2 _) (Expr expr3 _) =
   withGuPool $ \tmpPl ->