From 31ebedfd68116952a85477e36d107ed73c97bd9f Mon Sep 17 00:00:00 2001
From: Nicolas Wu <nicolas.wu@gmail.com>
Date: Sat, 3 Mar 2012 16:47:32 +0000
Subject: [PATCH] Fix discarded value warnings.

---
 Database/HDBC/PostgreSQL/Parser.hs     | 18 +++++++++---------
 Database/HDBC/PostgreSQL/Statement.hsc | 14 +++++++-------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/Database/HDBC/PostgreSQL/Parser.hs b/Database/HDBC/PostgreSQL/Parser.hs
index d5568ab..4c50d2e 100644
--- a/Database/HDBC/PostgreSQL/Parser.hs
+++ b/Database/HDBC/PostgreSQL/Parser.hs
@@ -13,43 +13,43 @@ escapeseq = (try $ string "''") <|>
             (try $ string "\\'")
 
 literal :: GenParser Char st [Char]
-literal = do char '\''
+literal = do _ <- char '\''
              s <- many (escapeseq <|> (noneOf "'" >>= (\x -> return [x])))
-             char '\''
+             _ <- char '\''
              return $ "'" ++ (concat s) ++ "'"
 
 qidentifier :: GenParser Char st [Char]
-qidentifier = do char '"'
+qidentifier = do _ <- char '"'
                  s <- many (noneOf "\"")
-                 char '"'
+                 _ <- char '"'
                  return $ "\"" ++ s ++ "\""
 
 comment :: GenParser Char st [Char]
 comment = ccomment <|> linecomment
 
 ccomment :: GenParser Char st [Char]
-ccomment = do string "/*"
+ccomment = do _ <- string "/*"
               c <- manyTill ((try ccomment) <|> 
                              (anyChar >>= (\x -> return [x])))
                    (try (string "*/"))
               return $ "/*" ++ concat c ++ "*/"
 
 linecomment :: GenParser Char st [Char]
-linecomment = do string "--"
+linecomment = do _ <- string "--"
                  c <- many (noneOf "\n")
-                 char '\n'
+                 _ <- char '\n'
                  return $ "--" ++ c ++ "\n"
 
 -- FIXME: handle pgsql dollar-quoted constants
 
 qmark :: (Num st, Show st) => GenParser Char st [Char]
-qmark = do char '?'
+qmark = do _ <- char '?'
            n <- getState
            updateState (+1)
            return $ "$" ++ show n
 
 escapedQmark :: GenParser Char st [Char]
-escapedQmark = do try (char '\\' >> char '?')
+escapedQmark = do _ <- try (char '\\' >> char '?')
                   return "?"
 
 statement :: (Num st, Show st) => GenParser Char st [Char]
diff --git a/Database/HDBC/PostgreSQL/Statement.hsc b/Database/HDBC/PostgreSQL/Statement.hsc
index 9f3f048..13c84bb 100644
--- a/Database/HDBC/PostgreSQL/Statement.hsc
+++ b/Database/HDBC/PostgreSQL/Statement.hsc
@@ -100,7 +100,7 @@ fexecuteRaw sstate =
             do l "in fexecute"
                public_ffinish sstate    -- Sets nextrowmv to -1
                resptr <- pqexec cconn cquery
-               handleResultStatus cconn resptr sstate =<< pqresultStatus resptr
+               _ <- handleResultStatus cconn resptr sstate =<< pqresultStatus resptr
                return ()
 
 handleResultStatus :: (Num a, Read a) => Ptr CConn -> WrappedCStmt -> SState -> ResultStatus -> IO a
@@ -109,28 +109,28 @@ handleResultStatus cconn resptr sstate status =
       #{const PGRES_EMPTY_QUERY} ->
           do l $ "PGRES_EMPTY_QUERY: " ++ squery sstate
              pqclear_raw resptr
-             swapMVar (coldefmv sstate) []
+             _ <- swapMVar (coldefmv sstate) []
              return 0
       #{const PGRES_COMMAND_OK} ->
           do l $ "PGRES_COMMAND_OK: " ++ squery sstate
              rowscs <- pqcmdTuples resptr
              rows <- peekCString rowscs
              pqclear_raw resptr
-             swapMVar (coldefmv sstate) []
+             _ <- swapMVar (coldefmv sstate) []
              return $ case rows of
                         "" -> 0
                         x -> read x
       #{const PGRES_TUPLES_OK} ->
           do l $ "PGRES_TUPLES_OK: " ++ squery sstate
-             fgetcoldef resptr >>= swapMVar (coldefmv sstate)
+             _ <- fgetcoldef resptr >>= swapMVar (coldefmv sstate)
              numrows <- pqntuples resptr
              if numrows < 1 then (pqclear_raw resptr >> return 0) else
                  do
                    wrappedptr <- withRawConn (dbo sstate)
                                  (\rawconn -> wrapstmt resptr rawconn)
                    fresptr <- newForeignPtr pqclearptr wrappedptr
-                   swapMVar (nextrowmv sstate) 0
-                   swapMVar (stomv sstate) (Just fresptr)
+                   _ <- swapMVar (nextrowmv sstate) 0
+                   _ <- swapMVar (stomv sstate) (Just fresptr)
                    return 0
       _ | resptr == nullPtr -> do
               l $ "PGRES ERROR: " ++ squery sstate
@@ -218,7 +218,7 @@ fexecutemany sstate arglist =
 public_ffinish :: SState -> IO ()
 public_ffinish sstate =
     do l "public_ffinish"
-       swapMVar (nextrowmv sstate) (-1)
+       _ <- swapMVar (nextrowmv sstate) (-1)
        modifyMVar_ (stomv sstate) worker
     where worker Nothing = return Nothing
           worker (Just sth) = ffinish sth >> return Nothing