-<?xml version="1.0" encoding="iso-8859-1"?>
-<sect1 id="release-5-04">
- <title>Release notes for version 5.04</title>
-
- <sect2>
- <title>User-visible compiler changes</title>
- <itemizedlist>
- <listitem>
- <para>Full support for MacOS X, including fully optimized compilation, has been added. Only a native
- code generator and support for <option>-split-objs</option> is still missing.
- Everything else needs more testing, but should work.</para>
- </listitem>
- <listitem>
- <para><literal>ghc-pkg</literal>: new options
- <option>--auto-ghci-libs</option>,
- <option>-u</option>/<option>--update-package</option>,
- <option>--force</option>, and
- <option>-i</option>/<option>--input-file</option>, and
- suppport for expanding environment variables in package
- descriptions. See <xref linkend="packages">).</para>
- </listitem>
- <listitem>
- <para>The latest version of the FFI spec is fully supported.
- The syntax of FFI declarations has changed accordingly. The
- old syntax is still accepted for the time being, but will
- elicit a warning from the compiler.</para>
- </listitem>
- <listitem>
- <para>New option: <option>-F</option> specifies a user-defined
- preprocessing phase (see <xref linkend="pre-processor">).</para>
- </listitem>
- <listitem>
- <para>Major overhaul of the heap profiling subsystem, with new
- facilities for retainer profiling and biographical profiling
- (ala nhc98, albeit with a couple of omissions). The syntax of
- the runtime heap-profiling options has changed. See <xref
- linkend="prof-heap">.</para>
- </listitem>
- <listitem>
- <para>The type system now supports full rank-N types
- (previously only limited rank-2 types were supported). See
- <xref linkend="universal-quantification">.</para>
- </listitem>
- <listitem>
- <para>Explicit kind annotations can now be given on any
- binding occurrence of a type variable. See <xref
- linkend="kinding">.</para>
- </listitem>
- <listitem>
- <para>The handling of type synonyms has been rationalised.
- See <xref linkend="type-synonyms">.</para>
- </listitem>
- <listitem>
- <para>Fixes for several space leaks in the compiler itself
- (these fixes were also merged into 5.02.3).</para>
- </listitem>
- <listitem>
- <para>It is now possible to derive arbitrary classes for
- newtypes. See <xref linkend="newtype-deriving">.</para>
- </listitem>
- <listitem>
- <para>Deadlock is now an exception, rather than a return
- status from the scheduler. See the module
- <literal>Control.Exception</literal> in the library
- documentation for more details.</para>
- </listitem>
- <listitem>
- <para>The syntax and behaviour of <literal>RULE</literal>
- pragmas has changed slightly. See <xref
- linkend="rewrite-rules">.</para>
- </listitem>
- <listitem>
- <para>Interface files are now in a binary format to reduce
- compilation times. To view an interface file in plain text,
- use the <option>--show-iface</option> flag.</para>
- </listitem>
- <listitem>
- <para>A restriction on the form of class declarations has been
- lifted. In Haskell 98, it is illegal for class method types
- to mention constraints on the class type variable. eg.</para>
-
-<programlisting>
- class Seq s a where
- elem :: Eq a => a -> s a -> Bool
-</programlisting>
-
- <para>This restriction has now been lifted in GHC.</para>
- </listitem>
- <listitem>
- <para>Main threads can now receive the
- <literal>BlockedOnDeadMVar</literal> exception in the same way
- as other threads.</para>
- </listitem>
- <listitem>
- <para>The <option>-fall-strict</option> flag never really
- worked, and has been removed.</para>
- </listitem>
- <listitem>
- <para>The syntax of <literal>.hi-boot</literal> files is now
- much clearer and Haskell-like. See <xref
- linkend="mutual-recursion">.</para>
- </listitem>
- <listitem>
- <para>There is a new flag <option>-fffi</option> which enables
- FFI support without turning on the rest of the GHC
- extensions.</para>
- </listitem>
- <listitem>
- <para>The syntax for implicit parameter bindings has changed.
- Previously the keyword <literal>with</literal> was used to
- introduce implicit bindings, but now implicit bindings may be
- introduced using <literal>let</literal> (see <xref
- linkend="implicit-parameters">). As a result of this,
- <literal>with</literal> is no longer a keyword when
- <option>-fglasgow-exts</option> is turned on.</para>
-
- <para>The option <literal>-fwith</literal> may be used to
- restore the old behaviour.</para>
- </listitem>
- <listitem>
- <para>Infix type constructors are now allowed, and must begin
- with a colon (as with data constructors). See <xref
- linkend="infix-tycons">.</para>
- </listitem>
- <listitem>
- <para>The <literal>do</literal>-notation syntax is now
- rebindable in the same way as other built-in syntax. See
- <xref linkend="rebindable-syntax">.</para>
- </listitem>
- <listitem>
- <para>Support for using “frameworks” on
- Darwin/MacOS X has been added. See the
- <option>-framework</option> option in <xref
- linkend="options-linker">, and the
- <literal>framework_dirs</literal> field of a package spec in
- <xref linkend="package-management">.</para>
- </listitem>
- </itemizedlist>
- </sect2>
-
- <sect2>
- <title>User-visible interpreter (GHCi) changes</title>
- <itemizedlist>
- <listitem>
- <para>New commands: <literal>:browse</literal>, <literal>:set
- args</literal>, <literal>:set prog</literal>, <literal>:show
- bindings</literal>, and <literal>:show modules</literal> (see
- <xref linkend="ghci-commands">).</para>
- </listitem>
- <listitem>
- <para>There is a much more flexible mechanism for manipulating
- the scope for expressions typed at the prompt. For example,
- one can now have both the <literal>Prelude</literal> and the
- exports of several compiled modules in scope at the same
- time. See <xref linkend="ghci-scope">.</para>
- </listitem>
- <listitem>
- <para>GHCi now supports <literal>foreign import
- "wrapper"</literal> FFI declarations.</para>
- </listitem>
- </itemizedlist>
- </sect2>
-
- <sect2>
- <title>User-visible library changes</title>
- <itemizedlist>
- <listitem>
- <para>GHC is in the process of moving to a new hierarchical
- set of libraries. At the moment, we have two sets of
- libraries, both described in accompanying documents:</para>
- <itemizedlist>
- <listitem>
- <para>The “new libraries” which are
- hierarchical and consist of the following packages:
- <literal>base</literal>, <literal>haskell98</literal>,
- <literal>haskell-src</literal>, and
- <literal>network</literal>. Broadly speaking,
- <literal>base</literal> contains the
- <literal>Prelude</literal>, standard libraries and most of
- the contents of the old <literal>lang</literal>
- package. By default, the <literal>base</literal> and
- <literal>haskell98</literal> packages are enabled.</para>
- </listitem>
-
- <listitem>
- <para>The <literal>hslibs</literal>, most of which are now
- deprecated. Where possible, new code should be written to
- use the new libraries instead. </para>
-
- <para>The following libraries in <literal>hslibs</literal>
- have not moved yet:</para>
- <itemizedlist>
- <listitem>
- <para>The packages <literal>win32</literal>,
- <literal>xlib</literal>, <literal>graphics</literal>,
- and <literal>posix</literal>.</para>
- </listitem>
- <listitem>
- <para>The Edison libraries in the
- <literal>data</literal> package.</para>
- </listitem>
- <listitem>
- <para>In the <literal>lang</literal> package, the
- modules <literal>TimeExts</literal>,
- <literal>DirectoryExts</literal>,
- <literal>SystemExts</literal>, and
- <literal>NumExts</literal>.</para>
- </listitem>
- <listitem>
- <para>The HaXml libraries in the
- <literal>text</literal> package.</para>
- </listitem>
- <listitem>
- <para>In the <literal>util</literal> package, the
- modules <literal>MD5</literal>,
- <literal>Select</literal>, <literal>Memo</literal>,
- <literal>Observe</literal>, and
- <literal>Readline</literal>.</para>
- </listitem>
- </itemizedlist>
-
- <para>All other libraries from <literal>hslibs</literal>
- either have equivalents in the new libraries (see the
- <literal>hslibs</literal> docs for details), or were
- already deprecated and hence were not moved into the new
- hierarchy.</para>
- </listitem>
- </itemizedlist>
- </listitem>
-
- <listitem>
- <para>The <literal>Read</literal> class is now based on a
- parsing combinator library which is vastly more efficient than
- the previous one. See the modules
- <literal>Text.Read</literal>.
- <literal>Text.ParserCombinators.ReadP</literal>, and
- <literal>Text.ParserCombinators.ReadPrec</literal> in the
- library documentation.</para>
-
- <para>The code generated by the compiler for derived
- <literal>Read</literal> instances should be much shorter than
- before.</para>
- </listitem>
- </itemizedlist>
- </sect2>
-
- <sect2>
- <title>New experimental features</title>
- <itemizedlist>
- <listitem>
- <para>Linear implicit parameters. See <xref
- linkend="linear-implicit-parameters">.</para>
- </listitem>
- <listitem>
- <para>The RTS has support for running in a multi-threaded
- environment and making non-blocking (from Haskell's point of
- view) calls to foreign C functions which would normally block.
- To enable this behaviour, configure with the
- <option>--enable-threaded-rts</option> option.</para>
- </listitem>
- <listitem>
- <para>The compiler can now read in files containing Core
- syntax (such as those produced by the
- <option>-fext-core</option> option) and compile them. Input
- files with the <literal>.hcr</literal> file extension are
- assumed to contain Core syntax.</para>
- </listitem>
- </itemizedlist>
- </sect2>
-
- <sect2>
- <title>Internal changes</title>
- <itemizedlist>
- <listitem>
- <para>Happy 1.13 is now required to build GHC, because of the
- change in names of certain libraries.</para>
- </listitem>
- </itemizedlist>
- </sect2>
-
-</sect1>
-
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