ghc/docs/users_guide/4-07-notes.sgml

   1 <sect1 id="release-4-07">
   2   <title>Release notes for version 4.07 (May 2000)</title>
   3
   4   <sect2>
   5     <title>User-visible compiler changes</title>
   6
   7     <itemizedlist>
   8       <listitem>
   9         <para>New profiling subsystem, based on cost-centre stacks.
  10         See <xref linkend="profiling">.</para>
  11       </listitem>
  12
  13       <listitem>
  14         <para>The x86 native code generator has been reworked
  15         considerably, and now works reliably.  Using the NCG rather
  16         than compiling via C reduces compilation times by roughly a
  17         half while having minimal effect on the run-time of the
  18         compiled program (about 2-4% slower, worse for floating-point
  19         intensive programs).</para>
  20
  21         <para>Add the <option>-fasm-x86</option> flag to GHC's command
  22         line to enable it.</para>
  23       </listitem>
  24
  25       <listitem>
  26         <para>Implicit parameters.  This Haskell extension gives a
  27         statically-typed version of dynamic scoping that avoids the
  28         worst problems of dynamic scoping in lisp.  See the
  29         <ulink url="http://www.cse.ogi.ed/~jlewis/implicit.ps.gz">POPL paper</ulink>
  30         for more details.  It is enabled by <option>-fglasgow-exts</option>.
  31         </para>
  32       </listitem>
  33
  34       <listitem>
  35         <para>New <literal>DEPRECATED</literal> pragma for marking
  36         outdated interfaces as deprecated.</para>
  37       </listitem>
  38
  39       <listitem>
  40         <para>New flag: <option>-fdump-minimal-imports</option>, which
  41         dumps a file <literal>M.imports</literal> that contains the
  42         (allegedly) minimal bunch of imports needed by the current
  43         module.</para>
  44       </listitem>
  45
  46       <listitem>
  47         <para>New &ldquo;package&rdquo; system for libraries.  See
  48         <xref linkend="packages"> for the details.</para>
  49       </listitem>
  50
  51       <listitem>
  52         <para>The long-standing bug that caused some programs which
  53         used <link linkend="trace"><literal>trace</literal></link> to
  54         exit with a deadlock error has been fixed.</para>
  55       </listitem>
  56
  57       <listitem>
  58         <para>Trying to put into a full <link
  59         linkend="sec-MVars"><literal>MVar</literal></link> will now
  60         raise a <link
  61         linkend="PutFullMVar"><literal>PutFullMVar</literal></link>
  62         exception.</para>
  63       </listitem>
  64
  65       <listitem>
  66         <para>If a thread is about to be garbage collected, because it
  67         is waiting on an <literal>MVar</literal> that no other thread
  68         has access to, then it will now be sent the <link
  69         linkend="BlockedOnDeadMVar"><literal>BlockedOnDeadMVar</literal></link>
  70         exception.</para>
  71       </listitem>
  72
  73       <listitem>
  74         <para>A thread that is found to be blocked against itself
  75         (i.e. is black holed) is now sent a
  76         <literal>NonTermination</literal> exception.</para>
  77       </listitem>
  78
  79       <listitem>
  80         <para>Operations which may <emphasis>block</emphasis>, such as
  81         <literal>takeMVar</literal>, <literal>raiseInThread</literal>,
  82         and several I/O operations, may now receive asynchronous
  83         exceptions even in the scope of a
  84         <literal>blockAsyncExceptions</literal>.  These are called
  85         <firstterm>interruptible</firstterm> operations.  See <xref
  86         linkend="interruptible-operations"> for more details.</para>
  87       </listitem>
  88
  89       <listitem>
  90         <para>Result type signatures now work.</para>
  91       </listitem>
  92
  93       <listitem>
  94         <para>A truckload of bugfixes.</para>
  95       </listitem>
  96
  97     </itemizedlist>
  98   </sect2>
  99
 100   <sect2>
 101     <title>User-visible library changes</title>
 102
 103     <itemizedlist>
 104       <listitem>
 105         <para>The FFI has been revised and expanded; see <xref
 106         linkend="sec-Foreign"> and <xref linkend="sec-CTypes">.</para>
 107       </listitem>
 108
 109       <listitem>
 110         <para>HaXml, a library for parsing and generating XML, has
 111         been added to the <literal>text</literal> package (<xref
 112         linkend="sec-haxml">).</para>
 113       </listitem>
 114
 115       <listitem>
 116         <para>The <literal>QuickCheck</literal> library for performing
 117         functional testing has been added to the
 118         <literal>util</literal> package.</para>
 119       </listitem>
 120
 121       <listitem>
 122         <para>Two new experimental interfaces to arrays:
 123         <literal>IArray</literal> for immutable arrays (<xref
 124         linkend="sec-iarray">), and <literal>MArray</literal> for
 125         mutable arrays (<xref linkend="sec-marray">).</para>
 126
 127         <para>Comments on these interfaces are welcome; eventually
 128         we'd like them to replace <literal>ByteArray</literal>,
 129         <literal>STArray</literal> and
 130         <literal>IOArray</literal>.</para>
 131       </listitem>
 132
 133       <listitem>
 134         <para>New function: <link
 135         linkend="tryTakeMVar"><literal>tryTakeMVar</literal></link>.</para>
 136       </listitem>
 137
 138       <listitem>
 139         <para><literal>MutableArray</literal> has gone away, use
 140         <literal>STArray</literal> (see <xref linkend="sec-ST">)
 141         instead.</para>
 142       </listitem>
 143
 144       <listitem>
 145         <para><literal>hPutBuf</literal>,
 146         <literal>hPutBufBA</literal>, <literal>hGetBuf</literal>, and
 147         <literal>hGetBufBA</literal>, have been renamed to
 148         <literal>hPutBufFull</literal>,
 149         <literal>hPutBufBAFull</literal>,
 150         <literal>hGetBufFull</literal>, and
 151         <literal>hGetBufBAFull</literal>.  Functions with the old
 152         names still exist, but have slightly different semantics.  See
 153         <xref linkend="sec-bulk-transfers"> for more details.</para>
 154       </listitem>
 155     </itemizedlist>
 156   </sect2>
 157
 158   <sect2>
 159     <title>Internal changes</title>
 160
 161     <itemizedlist>
 162       <listitem>
 163         <para><literal>Con</literal> is gone; the
 164         <literal>CoreExpr</literal> type is simpler.</para>
 165       </listitem>
 166
 167       <listitem>
 168         <para><literal>NoRepLits</literal> have gone.</para>
 169       </listitem>
 170
 171       <listitem>
 172         <para>Better usage info in interface files, which means less
 173         recompilation.</para>
 174       </listitem>
 175
 176       <listitem>
 177         <para>CCall primop is tidied up.</para>
 178       </listitem>
 179
 180       <listitem>
 181         <para>Constant folding now done by Rules.</para>
 182       </listitem>
 183
 184       <listitem>
 185         <para>Lots of hackery in the simplifier.</para>
 186       </listitem>
 187
 188       <listitem>
 189         <para>Improvements in CPR and strictness analysis.</para>
 190       </listitem>
 191
 192     </itemizedlist>
 193
 194   </sect2>
 195
 196 </sect1>
 197
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