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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/users_guide/6.14.1-notes.xml | 467 |
1 files changed, 461 insertions, 6 deletions
diff --git a/docs/users_guide/6.14.1-notes.xml b/docs/users_guide/6.14.1-notes.xml index e98970f193..5bb63d158a 100644 --- a/docs/users_guide/6.14.1-notes.xml +++ b/docs/users_guide/6.14.1-notes.xml @@ -29,58 +29,513 @@ </itemizedlist> </sect2> -<!-- <sect2> <title>Language changes</title> <itemizedlist> + <listitem> + <para> + GHC now understands the <literal>Haskell98</literal> and + <literal>Haskell2010</literal> languages. + </para> + + <para> + These get processed before the language extension pragmas, + and define the default sets of extensions that are enabled. + If neither is specified, then the default is + <literal>Haskell2010</literal> plus the + <literal>MonoPatBinds</literal> extension. + </para> + </listitem> + + <listitem> + <para> + GHC now supports the <literal>DoAndIfThenElse</literal> + extension, which is part of the Haskell 2010 standard. + </para> + </listitem> + + <listitem> + <para> + Datatype contexts, such as the <literal>Eq a</literal> in + </para> +<programlisting> +data Eq a => Set a = NilSet | ConsSet a (Set a) +</programlisting> + <para> + are now treated as an extension + <literal>DatatypeContexts</literal> (on by default) by GHC. + </para> + </listitem> + + <listitem> + <para> + GHC's support for unicode source has been improved, including + removing support for U+22EF for the <literal>..</literal> + symbol. See <xref linkend="unicode-syntax" /> for more details. + </para> + </listitem> + + <listitem> + <para> + Pragmas are now reread after preprocessing. In particular, + this means that if a pragma is used to turn CPP on, then other + pragmas can be put in CPP conditionals. + </para> + </listitem> + + <listitem> + <para> + The <literal>TypeOperators</literal> extension now allows + instance heads to use infix syntax. + </para> + </listitem> + + <listitem> + <para> + The <literal>PackageImports</literal> extension now understands + <literal>this</literal> to mean the current package. + </para> + </listitem> + + <listitem> + <para> + The <literal>INLINE</literal> and <literal>NOINLINE</literal> + pragmas can now take a <literal>CONLIKE</literal> modifier, + which indicates that the right hand side is cheap to compute, + and can thus be duplicated more freely. + See <xref linkend="conlike" /> for more details. + </para> + </listitem> + + <listitem> + <para> + A <literal>ForceSpecConstr</literal> annotation on a type, e.g. + </para> +<programlisting> +import SpecConstr +{-# ANN type SPEC ForceSpecConstr #-} +</programlisting> + <para> + can be used to force GHC to fully specialise argument of that + type. + </para> + </listitem> + + <listitem> + <para> + A <literal>NoSpecConstr</literal> annotation on a type, e.g. + </para> +<programlisting> +import SpecConstr +{-# ANN type T NoSpecConstr #-} +</programlisting> + <para> + can be used to prevent SpecConstr from specialising on + arguments of that type. + </para> + </listitem> + + <listitem> + <para> + There is are two experimental new extensions + <literal>AlternativeLayoutRule</literal> and + <literal>AlternativeLayoutRuleTransitional</literal>, + which are for exploring alternative layout rules in Haskell'. + The details are subject to change, so we advise against using + them in real code for now. + </para> + </listitem> + + <listitem> + <para> + The <literal>NewQualifiedOperators</literal> extension has + been deprecated, as it was rejected by the Haskell' committee. + </para> + </listitem> </itemizedlist> </sect2> <sect2> <title>Warnings</title> <itemizedlist> + <listitem> + <para> + There is now a warning for missing import lists, controlled + by the new <literal>-fwarn-missing-import-lists</literal> flag. + </para> + </listitem> + + <listitem> + <para> + GHC will now warn about <literal>SPECIALISE</literal> and + <literal>UNPACK</literal> pragmas that have no effect. + </para> + </listitem> </itemizedlist> </sect2> <sect2> - <title>Runtime system</title> - + <title>DLLs</title> <itemizedlist> + <listitem> + <para> + Shared libraries are once again supported on Windows. + </para> + </listitem> + + <listitem> + <para> + Shared libraries are now supported on OS X, both on x86 and on + PowerPC. The new <literal>-dylib-install-name</literal> GHC + flag is used to set the location of the dynamic library. + See <xref linkend="finding-shared-libs" /> for more details. + </para> + </listitem> </itemizedlist> </sect2> <sect2> - <title>Build system</title> + <title>Runtime system</title> + <itemizedlist> + <listitem> + <para> + For security reasons, by default, the only RTS flag that + programs accept is <literal>+RTS --info</literal>. If you want + the full range of RTS flags then you need to link with the new + <literal>-rtsopts</literal> flag. See + <xref linkend="options-linker" /> for more details. + </para> + </listitem> + + <listitem> + <para> + The RTS now exports a function <literal>setKeepCAFs</literal> + which is important when loading Haskell DLLs dynamically, as + a DLL may refer to CAFs that hae already been GCed. + </para> + </listitem> + + <listitem> + <para> + The garbage collector no longer allows you to specify a number + of steps; there are now always 2. The <literal>-T</literal> + RTS flag has thus been removed. + </para> + </listitem> + + <listitem> + <para> + A new RTS flag <literal>-H</literal> causes the RTS to use a + larger nursery, but without exceeding the amount of memory + that the application is already using. It makes some programs + go slower, but others go faster. + </para> + </listitem> + + <listitem> + <para> + GHC now returns memory to the OS, if memory usage peaks and + then drops again. This is mainly useful for long running + processes which normally use very little memory, but + occasionally need a lot of memory for a short period of time. + </para> + </listitem> + + <listitem> + <para> + On OS X, eventLog events are now available as DTrace probes. + </para> + </listitem> + + <listitem> + <para> + The PAPI support has been improved. The new RTS flag + <literal>-a#0x40000000</literal> can be used to tell the RTS + to collect the native PAPI event <literal>0x40000000</literal>. + </para> + </listitem> </itemizedlist> </sect2> <sect2> <title>Compiler</title> <itemizedlist> + <listitem> + <para> + GHC now defaults to <literal>--make</literal> mode, i.e. GHC + will chase dependencies for you automatically by default. + </para> + </listitem> + + <listitem> + <para> + GHC now includes an LLVM code generator. + </para> + <para> + This includes a number of new flags: + a flag to tell GHC to use LLVM, <literal>-fllvm</literal>; + a flag to dump the LLVM input ,<literal>-ddump-llvm</literal>; + flags to keep the LLVM intermediate files, + <literal>-keep-llvm-file</literal> and + <literal>-keep-llvm-files</literal>; + flags to set the location and options for the LLVM assembler, + optimiser and compiler, + <literal>-pgmla</literal>, + <literal>-pgmlo</literal>, + <literal>-pgmlc</literal>, + <literal>-optla</literal>, + <literal>-optlo</literal> and + <literal>-optlc</literal>. + </para> + </listitem> + + <listitem> + <para> + It is now possible to use <literal>-fno-code</literal> with + <literal>--make</literal>. + </para> + </listitem> + + <listitem> + <para> + The new flag <literal>-dsuppress-coercions</literal> controls + whether GHC prints coercions in core dumps. + </para> + </listitem> + + <listitem> + <para> + The inliner has been overhauled. The most significant + user-visible change is that only saturated functions are + inlined, e.g. + </para> +<programlisting> +(.) f g x = f (g x) +</programlisting> + <para> + would only be inlined if <literal>(.)</literal> is applied to 3 + arguments, while + </para> +<programlisting> +(.) f g = \x -> f (g x) +</programlisting> + <para> + will be inlined if only aplpied to 2 arguments. + </para> + </listitem> + + <listitem> + <para> + The <literal>-finline-if-enough-args</literal> flag is no + longer supported. + </para> + </listitem> + + <listitem> + <para> + Column numbers in warnings and error messages now start at 1, + as is more standard, rather than 0. + </para> + </listitem> + + <listitem> + <para> + GHCi now understands most linker scripts. In particular, this + means that GHCi is able to load the C pthread library. + </para> + </listitem> + + <listitem> + <para> + The <literal>ghc --info</literal> output has been updated: + </para> + <para> + It now includes the + location of the global package database, in the + <literal>Global Package DB</literal> field. + </para> + <para> + It now includes the build, host and target platforms, in the + <literal>Build platform</literal>, + <literal>Host platform</literal> and + <literal>Target platform</literal> fields. + </para> + <para> + It now includes a <literal>Have llvm code generator</literal> + field. + </para> + <para> + The <literal>Win32 DLLs</literal> field has been removed. + </para> + </listitem> + + <listitem> + <para> + The registerised via-C backend, and the + <literal>-fvia-C</literal>, have been deprecated. The poor + floating-point performance in the x86 native code generator + has now been fixed, so we don't believe there is still any + reason to use the via-C backend. + </para> + </listitem> + + <listitem> + <para> + There is now a new flag <literal>--supported-extensions</literal>, + which currently behaves the same as + <literal>--supported-languages</literal>. + </para> + </listitem> + + <listitem> + <para> + GHC progress output such as + </para> +<programlisting> +[ 1 of 5] Compiling Foo ( Foo.hs, Foo.o ) +</programlisting> + <para> + is now sent to stdout rather than stderr. + </para> + </listitem> + + <listitem> + <para> + The new flag <literal>-fexpose-all-unfoldings</literal> + makes GHC put unfoldings for <emphasis>everything</emphasis> + in the interface file. + </para> + </listitem> + + <listitem> + <para> + There are two new flags, <literal>-fno-specialise</literal> + and <literal>-fno-float-in</literal>, for disabling the + specialise and float-in passes. + </para> + </listitem> + + <listitem> + <para> + The new flag <literal>-fstrictness-before=<replaceable>n</replaceable></literal> tells + GHC to run an additional strictness analysis pass + before simplifier phase <replaceable>n</replaceable>. + </para> + </listitem> + + <listitem> + <para> + There is a new flag + <literal>-funfolding-dict-discount</literal> + for tweaking the optimiser's behaviour. + </para> + </listitem> + + <listitem> + <para> + The <literal>-fspec-inline-join-points</literal> flag has been + removed. + </para> + </listitem> </itemizedlist> </sect2> <sect2> <title>GHCi</title> <itemizedlist> + <listitem> + <para> + GHCi now supports full import syntax, e.g. + </para> +<programlisting> +Prelude> import Data.List as L +Prelude Data.List> L.length "foo" +3 +</programlisting> + </listitem> + + <listitem> + <para> + GHCi now understands the layout of multiline-commands, so + this now works: + </para> +<programlisting> +Prelude> :{ +Prelude| let x = 1 +Prelude| y = 2 in x + y +Prelude| :} +3 +</programlisting> + </listitem> </itemizedlist> </sect2> <sect2> - <title>Template Haskell</title> + <title>Template Haskell and Quasi-Quoters</title> <itemizedlist> + <listitem> + <para> + It is now possible to quasi-quote patterns with + <literal>[p| ... |]</literal>. + </para> + </listitem> + + <listitem> + <para> + It is no longer to use a <literal>$</literal> before the + name of a quasi-quoter, e.g. one can now say + <literal>[expr| ... |]</literal> rather than + <literal>[$expr| ... |]</literal>. + </para> + </listitem> + + <listitem> + <para> + It is now possible to use a quasi-quoter for types, e.g. + <literal>f :: [$qq| ... |]</literal> + </para> + </listitem> + + <listitem> + <para> + It is now possible to quasi-quote existentials and GADTs. + </para> + </listitem> </itemizedlist> </sect2> <sect2> - <title>Package Handling</title> + <title>GHC API</title> <itemizedlist> + <listitem> + <para> + There are now <literal>Data</literal> and + <literal>Typeable</literal> instances for the + HsSyn typed. + </para> + </listitem> + + <listitem> + <para> + As language extensions are not applied until after the base + language (Haskell98, Haskell2010 or the default) has been + selected, it is now necessary to tell the GHC API the point + at which the extension flags should be processed. Normally + this is done by calling + <literal>DynFlags.flattenExtensionFlags</literal> once all + the flags and pragmas have been read. + </para> + </listitem> </itemizedlist> </sect2> +<!-- <sect2> <title>Libraries</title> + + <itemizedlist> + </itemizedlist> </sect2> --> </sect1> |