<sect1>Release notes for version~2.02---3/97
<label id="release-2-02">
<p>

Release~2.02 is the first release of Glasgow Haskell for Haskell~1.4.

The announcement for this release is distributed as @ANNOUNCE-2.02@
in the top-level directory.  It contains very important caveats about
2.02, which we do not repeat here!

Information about ``what's ported to which machine'' is in the
Installation Guide.  Since 2.01, we've added support for Win32
(Windows NT and Windows 95).

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<sect1>New configuration things in 2.02
<label id="2-02-config">
<p>
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<sect1>User-visible changes in 2.02, including incompatibilities
<label id="2-02-user-visible">
<p>
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GHC~2.02 is a compiler for Haskell~1.4 and, as such, introduces a
bunch of user-visible changes.  The GHC user's guide has a section to
help you upgrade your programs to Haskell~1.4 from 1.2; all
user-visible changes are described there (and not repeated here).

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<sect1>New or changed GHC command-line options
<label id="2-02-options">
<p>
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<itemize>
<item> GHC now warns of possibly-incomplete patterns in case expressions
and function bindings.  You can suppress these warnings with @-fno-warn-incomplete-patterns@.

GHC also warns of completely overlapped patterns.  You can't switch this off.

<item> GHC can warn of shadowed names, though it does not do so by default.  
Just occasionally this shows up 
an otherwise hard-to-find bug.  To warn of shadowed names use @-fwarn-name-shadowing@

<item> You can now generate `make' dependencies via the compiler
driver, use the option @-M@ together with the list source files to compute
the dependencies for. By default, the dependencies will be appended to
the file @Makefile@ in the current directory.

<item> For hackers, the flag @-dshow-rn-trace@ shows what the renamer is up to.
Sit back and marvel.

</itemize>


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<sect1>New in the compiler proper
<label id="2-02-new-in-compiler">
<p>
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<itemize>
<item>
Completely new ``make-world'' system, properly documented (at last) in the
installation guide.  No Jmakefiles; but you *need* Gnu make
(gmake). The more recent the better (v 3.70+).

<item>
The ``renamer''---the part of the compiler that implements
the Haskell module system---has been completely rewritten, again.

The format of interface files has changed significantly.  Interface files
generated by 2.01 will not work with 2.02.

<item>
Even less special pleading for the Prelude than in 2.01.  If you wanted
to write your own Prelude and drop it in, you would have
a really good chance now.
</itemize>


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<sect1>In the libraries
<label id="2-02-new-in-libraries">
<p>
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The libraries have been completely reorganised.  There's a description
in Section <ref name="System Libraries" id="syslibs">.


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<sect1>In ``hslibs'' libraries
<label id="2-02-new-in-syslibs">
<p>
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<sect1>In the runtime system
<label id="2-02-new-in-rts">
<p>
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<itemize>
<item> @ForeignObjs@ are properly deallocated when execution halts, as well
as when the garbage collector spots the @ForeignObj@ as being unreferenced.
This is important if you are using a @ForeignObj@ to refer to
a @COM@ object or other remote resource. You want that resource to be relased
when the program terminates.

<item> Files handles in the IO prelude are implemented using
@ForeignObjs@, and closed when the file handle is unreferenced.  This
means that if you open zillions of files then just letting go of the
file handle is enough to close it. 
</itemize>

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<sect1>Other new stuff
<label id="2-02-new-elsewhere">
<p>
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2.02 is released together with Green Card, a foreign-language
interface generator for Haskell. More details elsewhere...


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<sect1>Known troublespots
<label id="2-02-troublespots">
<p>
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The 2.02 compiler has the following known deficiencies:

<descrip>
<tag>native code generator, x86:</tag>

The native code generator for x86 platforms is by default switched
off, as the code the compiler produces with it enabled was discovered
just before releaseing to be wonky. Rather than delay the release
further, GHC on x86 platforms rely on @GCC@ as their
backend for now. Hopefully fixed soon.

<tag>Simplifier looping:</tag>

The simplifier(Glasgow-speak for optimiser) has been observed to get
into a loop in one or two cases. If you should observe this, please
report it as a bug - the work around is to turn off optimisation.

<tag>Undefined @*_vap_info@ symbols:</tag>

If the linker complains about some undefined @*_vap_info@ symbols when
linking 2.02 compiled programs (very unlikely) - fix this by compiling
the module where the references are coming from with
@-fno-lambda-lifting@.

</descrip>