ross:
I propose adding the following functions to System.IO:
-- | @'withFile' name mode act@ opens a file using 'openFile' and passes -- the resulting handle to the computation @act@. The handle will be -- closed on exit from 'withFile', whether by normal termination or by -- raising an exception. withFile :: FilePath -> IOMode -> (Handle -> IO r) -> IO r withFile name mode = bracket (openFile name mode) hClose
-- | @'withBinaryFile' name mode act@ opens a file using 'openBinaryFile' -- and passes the resulting handle to the computation @act@. The handle -- will be closed on exit from 'withBinaryFile', whether by normal -- termination or by raising an exception. withBinaryFile :: FilePath -> IOMode -> (Handle -> IO r) -> IO r withBinaryFile name mode = bracket (openBinaryFile name mode) hClose
(bracket is the one from Control.Exception, if available, else the one from System.IO.Error)
These functions are close to the Fairbairn Threshold, but just above it, I think, and worth naming because they wrap up a pattern that should be encouraged.
Yes, I agree. We could do with these in Data.ByteString too. +1 -- Don