-- GENERATED by C->Haskell Compiler, version 0.16.4 Crystal Seed, 24 Jan 2009 (Haskell) -- Edit the ORIGNAL .chs file instead! {-# LINE 1 "lib/CPython/Protocols/Iterator.chs" #-}{-# LANGUAGE ForeignFunctionInterface #-} -- Copyright (C) 2009 John Millikin <jmillikin@gmail.com> -- -- This program is free software: you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation, either version 3 of the License, or -- any later version. -- -- This program is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with this program. If not, see <http://www.gnu.org/licenses/>. module CPython.Protocols.Iterator ( Iterator (..) , SomeIterator , castToIterator , next ) where import CPython.Internal -- | Attempt to convert an object to a generic 'Iterator'. If the object does -- not implement the iterator protocol, returns 'Nothing'. castToIterator :: Object a => a -> IO (Maybe SomeIterator) castToIterator obj = withObject obj $ \objPtr -> do isIter <- fmap cToBool $ hscpythonPyIterCheck objPtr return $ if isIter then Just $ unsafeCastToIterator obj else Nothing -- | Return the next value from the iteration, or 'Nothing' if there are no -- remaining items. next :: Iterator iter => iter -> IO (Maybe SomeObject) next iter = withObject iter $ \iterPtr -> do raw <- pyIterNext iterPtr if raw == nullPtr then do err <- pyErrOccurred {-# LINE 47 "lib/CPython/Protocols/Iterator.chs" #-} exceptionIf $ err /= nullPtr return Nothing else fmap Just $ stealObject raw foreign import ccall safe "CPython/Protocols/Iterator.chs.h hscpython_PyIter_Check" hscpythonPyIterCheck :: ((Ptr ()) -> (IO CInt)) foreign import ccall safe "CPython/Protocols/Iterator.chs.h PyIter_Next" pyIterNext :: ((Ptr ()) -> (IO (Ptr ()))) foreign import ccall safe "CPython/Protocols/Iterator.chs.h PyErr_Occurred" pyErrOccurred :: (IO (Ptr ()))