1. 23 Jan, 2017 1 commit
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  3. 10 Jan, 2017 1 commit
  4. 04 Aug, 2016 1 commit
  5. 06 Jun, 2016 1 commit
  6. 23 Dec, 2015 1 commit
    • Eric Seidel's avatar
      Allow CallStacks to be frozen · 380b25ea
      Eric Seidel authored
      This introduces "freezing," an operation which prevents further
      locations from being appended to a CallStack.  Library authors may want
      to prevent CallStacks from exposing implementation details, as a matter
      of hygiene. For example, in
      head [] = error "head: empty list"
      ghci> head []
      *** Exception: head: empty list
      CallStack (from implicit params):
        error, called at ...
      including the call-site of `error` in `head` is not strictly necessary
      as the error message already specifies clearly where the error came
      So we add a function `freezeCallStack` that wraps an existing CallStack,
      preventing further call-sites from being pushed onto it. In other words,
      pushCallStack callSite (freezeCallStack callStack) = freezeCallStack callStack
      Now we can define `head` to not produce a CallStack at all
      head [] =
        let ?callStack = freezeCallStack emptyCallStack
        in error "head: empty list"
      ghci> head []
      *** Exception: head: empty list
      CallStack (from implicit params):
        error, called at ...
      1. We add the `freezeCallStack` and `emptyCallStack` and update the
         definition of `CallStack` to support this functionality.
      2. We add `errorWithoutStackTrace`, a variant of `error` that does not
         produce a stack trace, using this feature. I think this is a sensible
         wrapper function to provide in case users want it.
      3. We replace uses of `error` in base with `errorWithoutStackTrace`. The
         rationale is that base does not export any functions that use CallStacks
         (except for `error` and `undefined`) so there's no way for the stack
         traces (from Implicit CallStacks) to include user-defined functions.
         They'll only contain the call to `error` itself. As base already has a
         good habit of providing useful error messages that name the triggering
         function, the stack trace really just adds noise to the error. (I don't
         have a strong opinion on whether we should include this third commit,
         but the change was very mechanical so I thought I'd include it anyway in
         case there's interest)
      4. Updates tests in `array` and `stm` submodules
      Test Plan: ./validate, new test is T11049
      Reviewers: simonpj, nomeata, goldfire, austin, hvr, bgamari
      Reviewed By: simonpj
      Subscribers: thomie
      Projects: #ghc
      Differential Revision: https://phabricator.haskell.org/D1628
      GHC Trac Issues: #11049
  7. 25 Sep, 2015 1 commit
    • Ben Gamari's avatar
      Weak: Don't require wrapping/unwrapping of finalizers · fb409264
      Ben Gamari authored
      To quote Simon Marlow,
          We don't expect users to ever write code that uses mkWeak# or
          finalizeWeak#, we have safe interfaces to these. Let's document the type
          unsafety and fix the problem with () without introducing any overhead.
      Updates stm submodule.
  8. 24 Sep, 2015 1 commit
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  13. 27 May, 2014 1 commit
    • Herbert Valerio Riedel's avatar
      Replace DeriveDataTypeable by AutoDeriveTypeable · 6ed54303
      Herbert Valerio Riedel authored
      This is a first step towards addressing #9111
      This results in the following additional Typeable (exported) instances
      being generated (list was compiled by diff'ing hoogle txt output):
        instance Typeable CFile
        instance Typeable 'CFile
        instance Typeable CFpos
        instance Typeable 'CFpos
        instance Typeable CJmpBuf
        instance Typeable 'CJmpBuf
        instance Typeable ChItem
        instance Typeable QSem
        instance Typeable ID
        instance Typeable 'ID
        instance Typeable CONST
        instance Typeable Qi
        instance Typeable Qr
        instance Typeable Mp
        instance Typeable ConstrRep
        instance Typeable Fixity
        instance Typeable 'Prefix
        instance Typeable 'Infix
        instance Typeable Constr
        instance Typeable DataType
        instance Typeable DataRep
        instance Typeable Data
        instance Typeable HasResolution
        instance Typeable IsList
      Signed-off-by: Herbert Valerio Riedel's avatarHerbert Valerio Riedel <hvr@gnu.org>
  14. 22 Sep, 2013 1 commit
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  16. 15 Jun, 2013 1 commit
  17. 06 Jun, 2013 1 commit
    • Simon Peyton Jones's avatar
      Re-jig SOURCE imports · 8d87b5bf
      Simon Peyton Jones authored
      * Do not have have an hs-boot file for Data.Typeable
      * Instead make all the loops go through
           GHC.Err (just a couple of magic functions)
           GHC.Exception (some non-exceptional functions)
      The main idea is
        a) don't involve classes in the hs-boot world
        b) loop through error cases where performance doesn't matter
        c) be careful not to SOURCE import things that are bottom,
           unless MkCore knows about them in eRROR_IDS, so that we
           see their strictness
  18. 21 Aug, 2012 1 commit
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  30. 25 Nov, 2009 2 commits
  31. 06 Jul, 2009 1 commit
  32. 12 Jun, 2009 1 commit
    • Simon Marlow's avatar
      Rewrite of the IO library, including Unicode support · 7b067f2d
      Simon Marlow authored
      * Unicode support for Handle I/O:
        ** Automatic encoding and decoding using a per-Handle encoding.
        ** The encoding defaults to the locale encoding (only on Unix 
           so far, perhaps Windows later).
        ** Built-in UTF-8, UTF-16 (BE/LE), and UTF-32 (BE/LE) codecs.
        ** iconv-based codec for other encodings on Unix
      * Modularity: the low-level IO interface is exposed as a type class
        (GHC.IO.IODevice) so you can build your own low-level IO providers and
        make Handles from them.
      * Newline translation: instead of being Windows-specific wired-in
        magic, the translation from \r\n -> \n and back again is available
        on all platforms and is configurable for reading/writing
      Unicode-aware Handles
      This is a significant restructuring of the Handle implementation with
      the primary goal of supporting Unicode character encodings.
      The only change to the existing behaviour is that by default, text IO
      is done in the prevailing locale encoding of the system (except on
      Windows [1]).  
      Handles created by openBinaryFile use the Latin-1 encoding, as do
      Handles placed in binary mode using hSetBinaryMode.
      We provide a way to change the encoding for an existing Handle:
         GHC.IO.Handle.hSetEncoding :: Handle -> TextEncoding -> IO ()
      and various encodings (from GHC.IO.Encoding):
         utf16, utf16le, utf16be,
         utf32, utf32le, utf32be,
      and a way to lookup other encodings:
         GHC.IO.Encoding.mkTextEncoding :: String -> IO TextEncoding
      (it's system-dependent whether the requested encoding will be
      We may want to export these from somewhere more permanent; that's a
      topic for a future library proposal.
      Thanks to suggestions from Duncan Coutts, it's possible to call
      hSetEncoding even on buffered read Handles, and the right thing
      happens.  So we can read from text streams that include multiple
      encodings, such as an HTTP response or email message, without having
      to turn buffering off (though there is a penalty for switching
      encodings on a buffered Handle, as the IO system has to do some
      re-decoding to figure out where it should start reading from again).
      If there is a decoding error, it is reported when an attempt is made
      to read the offending character from the Handle, as you would expect.
      Performance varies.  For "hGetContents >>= putStr" I found the new
      library was faster on my x86_64 machine, but slower on an x86.  On the
      whole I'd expect things to be a bit slower due to the extra
      decoding/encoding, but probabaly not noticeably.  If performance is
      critical for your app, then you should be using bytestring and text
      [1] Note: locale encoding is not currently implemented on Windows due
      to the built-in Win32 APIs for encoding/decoding not being sufficient
      for our purposes.  Ask me for details.  Offers of help gratefully
      Newline Translation
      In the old IO library, text-mode Handles on Windows had automatic
      translation from \r\n -> \n on input, and the opposite on output.  It
      was implemented using the underlying CRT functions, which meant that
      there were certain odd restrictions, such as read/write text handles
      needing to be unbuffered, and seeking not working at all on text
      In the rewrite, newline translation is now implemented in the upper
      layers, as it needs to be since we have to perform Unicode decoding
      before newline translation.  This means that it is now available on
      all platforms, which can be quite handy for writing portable code.
      For now, I have left the behaviour as it was, namely \r\n -> \n on
      Windows, and no translation on Unix.  However, another reasonable
      default (similar to what Python does) would be to do \r\n -> \n on
      input, and convert to the platform-native representation (either \r\n
      or \n) on output.  This is called universalNewlineMode (below).
      The API is as follows.  (available from GHC.IO.Handle for now, again
      this is something we will probably want to try to get into System.IO
      at some point):
      -- | The representation of a newline in the external file or stream.
      data Newline = LF    -- ^ "\n"
                   | CRLF  -- ^ "\r\n"
                   deriving Eq
      -- | Specifies the translation, if any, of newline characters between
      -- internal Strings and the external file or stream.  Haskell Strings
      -- are assumed to represent newlines with the '\n' character; the
      -- newline mode specifies how to translate '\n' on output, and what to
      -- translate into '\n' on input.
      data NewlineMode 
        = NewlineMode { inputNL :: Newline,
                          -- ^ the representation of newlines on input
                        outputNL :: Newline
                          -- ^ the representation of newlines on output
                   deriving Eq
      -- | The native newline representation for the current platform
      nativeNewline :: Newline
      -- | Map "\r\n" into "\n" on input, and "\n" to the native newline
      -- represetnation on output.  This mode can be used on any platform, and
      -- works with text files using any newline convention.  The downside is
      -- that @readFile a >>= writeFile b@ might yield a different file.
      universalNewlineMode :: NewlineMode
      universalNewlineMode  = NewlineMode { inputNL  = CRLF, 
                                            outputNL = nativeNewline }
      -- | Use the native newline representation on both input and output
      nativeNewlineMode    :: NewlineMode
      nativeNewlineMode     = NewlineMode { inputNL  = nativeNewline, 
                                            outputNL = nativeNewline }
      -- | Do no newline translation at all.
      noNewlineTranslation :: NewlineMode
      noNewlineTranslation  = NewlineMode { inputNL  = LF, outputNL = LF }
      -- | Change the newline translation mode on the Handle.
      hSetNewlineMode :: Handle -> NewlineMode -> IO ()
      IO Devices
      The major change here is that the implementation of the Handle
      operations is separated from the underlying IO device, using type
      classes.  File descriptors are just one IO provider; I have also
      implemented memory-mapped files (good for random-access read/write)
      and a Handle that pipes output to a Chan (useful for testing code that
      writes to a Handle).  New kinds of Handle can be implemented outside
      the base package, for instance someone could write bytestringToHandle.
      A Handle is made using mkFileHandle:
      -- | makes a new 'Handle'
      mkFileHandle :: (IODevice dev, BufferedIO dev, Typeable dev)
                    => dev -- ^ the underlying IO device, which must support
                           -- 'IODevice', 'BufferedIO' and 'Typeable'
                    -> FilePath
                           -- ^ a string describing the 'Handle', e.g. the file
                           -- path for a file.  Used in error messages.
                    -> IOMode
                           -- ^ The mode in which the 'Handle' is to be used
                    -> Maybe TextEncoding
                           -- ^ text encoding to use, if any
                    -> NewlineMode
                           -- ^ newline translation mode
                    -> IO Handle
      This also means that someone can write a completely new IO
      implementation on Windows based on native Win32 HANDLEs, and
      distribute it as a separate package (I really hope somebody does
      This restructuring isn't as radical as previous designs.  I haven't
      made any attempt to make a separate binary I/O layer, for example
      (although hGetBuf/hPutBuf do bypass the text encoding and newline
      translation).  The main goal here was to get Unicode support in, and
      to allow others to experiment with making new kinds of Handle.  We
      could split up the layers further later.
      API changes and Module structure
      NB. GHC.IOBase and GHC.Handle are now DEPRECATED (they are still
      present, but are just re-exporting things from other modules now).
      For 6.12 we'll want to bump base to version 5 and add a base4-compat.
      For now I'm using #if __GLASGOW_HASKEL__ >= 611 to avoid deprecated
      I split modules into smaller parts in many places.  For example, we
      now have GHC.IORef, GHC.MVar and GHC.IOArray containing the
      implementations of IORef, MVar and IOArray respectively.  This was
      necessary for untangling dependencies, but it also makes things easier
      to follow.
      The new module structurue for the IO-relatied parts of the base
      package is:
         Implementation of the IO monad; unsafe*; throw/catch
         The IOMode type
         Buffers and operations on them
         The IODevice and RawIO classes.
         The BufferedIO class.
         The FD type, with instances of IODevice, RawIO and BufferedIO.
         IO-related Exceptions
         The TextEncoding type; built-in TextEncodings; mkTextEncoding
         Implementation internals for GHC.IO.Encoding
         The main API for GHC's Handle implementation, provides all the Handle
         operations + mkFileHandle + hSetEncoding.
         Implementation of Handles and operations.
         Parts of the Handle API implemented by file-descriptors: openFile,
         stdin, stdout, stderr, fdToHandle etc.
  33. 24 Apr, 2009 1 commit
  34. 05 Mar, 2009 1 commit
    • Simon Marlow's avatar
      Partial fix for #2917 · 7fc5bad1
      Simon Marlow authored
       - add newAlignedPinnedByteArray# for allocating pinned BAs with
         arbitrary alignment
       - the old newPinnedByteArray# now aligns to 16 bytes
      Foreign.alloca will use newAlignedPinnedByteArray#, and so might end
      up wasting less space than before (we used to align to 8 by default).
      Foreign.allocaBytes and Foreign.mallocForeignPtrBytes will get 16-byte
      aligned memory, which is enough to avoid problems with SSE
      instructions on x86, for example.
      There was a bug in the old newPinnedByteArray#: it aligned to 8 bytes,
      but would have failed if the header was not a multiple of 8
      (fortunately it always was, even with profiling).  Also we
      occasionally wasted some space unnecessarily due to alignment in
      I haven't done anything about Foreign.malloc/mallocBytes, which will
      give you the same alignment guarantees as malloc() (8 bytes on
      Linux/x86 here).
  35. 10 Dec, 2008 1 commit
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