System.Posix.IO.ByteString types?
Recently, I spent a fair amount of time tracking down an encoding issue[1] in the `serialport` package. As is often the case, `serialport` used Strings, which blew up quite nicely when working with a binary protocol. Delving into the code it eventually became fairly obvious that the problem was due to encoding and could be fixed by completely moving to ByteStrings. Unfortunately, while the unix package contains a System.Posix.IO.ByteString module, all of the functions within still appear to work with Strings[2]. While it appears that paths are handled a bit differently in the ByteString variant, but it seems like this is a fairly small consideration compared to the data itself. Have I stumbled across a bug? Is there anyway short of the non-Haskell Platform unix-bytestring package to get ByteStrings out of fds? If not, it seems this is a large hole in the interfaces exposed by unix. Is there any plan to remedy this? Cheers, - Ben [1] https://github.com/jputcu/serialport/issues/12 [2] http://hackage.haskell.org/packages/archive/unix/2.5.1.1/doc/html/System-Pos...
On 05/07/2012 09:57, Ben Gamari wrote:
Recently, I spent a fair amount of time tracking down an encoding issue[1] in the `serialport` package. As is often the case, `serialport` used Strings, which blew up quite nicely when working with a binary protocol. Delving into the code it eventually became fairly obvious that the problem was due to encoding and could be fixed by completely moving to ByteStrings.
Unfortunately, while the unix package contains a System.Posix.IO.ByteString module, all of the functions within still appear to work with Strings[2]. While it appears that paths are handled a bit differently in the ByteString variant, but it seems like this is a fairly small consideration compared to the data itself.
Have I stumbled across a bug? Is there anyway short of the non-Haskell Platform unix-bytestring package to get ByteStrings out of fds? If not, it seems this is a large hole in the interfaces exposed by unix. Is there any plan to remedy this?
The .ByteString variants of the modules in System.Posix were added primarily to address the problem that FilePath was represented as String in the existing System.Posix APIs, but POSIX file paths are really sequences of bytes. Making ByteString versions of fdRead and fdWrite is a separate issue; but an important one undoubtedly. If there's general agreement on what the API should be, and if someone writes a patch, I'd be happy to apply it. Cheers, Simon
On 7/5/12 4:57 AM, Ben Gamari wrote:
Recently, I spent a fair amount of time tracking down an encoding issue[1] in the `serialport` package. As is often the case, `serialport` used Strings, which blew up quite nicely when working with a binary protocol. Delving into the code it eventually became fairly obvious that the problem was due to encoding and could be fixed by completely moving to ByteStrings.
Unfortunately, while the unix package contains a System.Posix.IO.ByteString module, all of the functions within still appear to work with Strings[2]. While it appears that paths are handled a bit differently in the ByteString variant, but it seems like this is a fairly small consideration compared to the data itself.
It is indeed a small consideration, IMO. In order to use ByteStrings as the medium of the data being exchanged, you want to use the unix-bytestring library[1]. Unfortunately that may be taxing on newer GHCs since the new version of unix stole the namespaces from unix-bytestring. I had tried to get unix-bytestring incorporated into unix previously (before unix's .ByteString modules existed), but made the unfortunate decision to emulate the String-based API--- and noone liked the old API to begin with, so the proposal was rejected. I've since modified the API to what I think is a nice design. It closely mirrors the official POSIX and XPG standards, and has been battle-tested by myself and other folks who were eschewing the unix package and doing their own ByteString-based operations. I'd love for unix-bytestring to be folded into unix itself, but have no time to make another proposal. If you'd like to do so on my behalf, feel free. [1] http://hackage.haskell.org/package/unix-bytestring -- Live well, ~wren
participants (4)
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Bas van Dijk -
Ben Gamari -
Simon Marlow -
wren ng thornton