- </term>
- <listitem>
- <para>This simultaneously enables all of the extensions to
- Haskell 98 described in <xref
- linkend="ghc-language-features"/>, except where otherwise
- noted. We are trying to move away from this portmanteau flag,
- and towards enabling features individaully.</para>
-
- <para>New reserved words: <literal>forall</literal> (only in
- types), <literal>mdo</literal>.</para>
-
- <para>Other syntax stolen:
- <replaceable>varid</replaceable>{<literal>#</literal>},
- <replaceable>char</replaceable><literal>#</literal>,
- <replaceable>string</replaceable><literal>#</literal>,
- <replaceable>integer</replaceable><literal>#</literal>,
- <replaceable>float</replaceable><literal>#</literal>,
- <replaceable>float</replaceable><literal>##</literal>,
- <literal>(#</literal>, <literal>#)</literal>,
- <literal>|)</literal>, <literal>{|</literal>.</para>
-
- <para>Implies these specific language options:
- <option>-XForeignFunctionInterface</option>,
- <option>-XImplicitParams</option>,
- <option>-XScopedTypeVariables</option>,
- <option>-XGADTs</option>,
- <option>-XTypeFamilies</option>. </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XForeignFunctionInterface</option>:
- <indexterm><primary><option>-XForeignFunctionInterface</option></primary></indexterm>
- </term>
- <listitem>
- <para>This option enables the language extension defined in the
- Haskell 98 Foreign Function Interface Addendum.</para>
-
- <para>New reserved words: <literal>foreign</literal>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XMonomorphismRestriction</option>,<option>-XMonoPatBinds</option>:
- </term>
- <listitem>
- <para> These two flags control how generalisation is done.
- See <xref linkend="monomorphism"/>.
- </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XExtendedDefaultRules</option>:
- <indexterm><primary><option>-XExtendedDefaultRules</option></primary></indexterm>
- </term>
- <listitem>
- <para> Use GHCi's extended default rules in a regular module (<xref linkend="extended-default-rules"/>).
- Independent of the <option>-fglasgow-exts</option>
- flag. </para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XOverlappingInstances</option>
- <indexterm><primary><option>-XOverlappingInstances</option></primary></indexterm>
- </term>
- <term>
- <option>-XUndecidableInstances</option>
- <indexterm><primary><option>-XUndecidableInstances</option></primary></indexterm>
- </term>
- <term>
- <option>-XIncoherentInstances</option>
- <indexterm><primary><option>-XIncoherentInstances</option></primary></indexterm>
- </term>
- <term>
- <option>-fcontext-stack=N</option>
- <indexterm><primary><option>-fcontext-stack</option></primary></indexterm>
- </term>
- <listitem>
- <para> See <xref linkend="instance-decls"/>. Only relevant
- if you also use <option>-fglasgow-exts</option>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-finline-phase</option>
- <indexterm><primary><option>-finline-phase</option></primary></indexterm>
- </term>
- <listitem>
- <para>See <xref linkend="rewrite-rules"/>. Only relevant if
- you also use <option>-fglasgow-exts</option>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XArrows</option>
- <indexterm><primary><option>-XArrows</option></primary></indexterm>
- </term>
- <listitem>
- <para>See <xref linkend="arrow-notation"/>. Independent of
- <option>-fglasgow-exts</option>.</para>
-
- <para>New reserved words/symbols: <literal>rec</literal>,
- <literal>proc</literal>, <literal>-<</literal>,
- <literal>>-</literal>, <literal>-<<</literal>,
- <literal>>>-</literal>.</para>
-
- <para>Other syntax stolen: <literal>(|</literal>,
- <literal>|)</literal>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term>
- <option>-XGenerics</option>
- <indexterm><primary><option>-XGenerics</option></primary></indexterm>
- </term>
- <listitem>
- <para>See <xref linkend="generic-classes"/>. Independent of
- <option>-fglasgow-exts</option>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>-XNoImplicitPrelude</option></term>
- <listitem>
- <para><indexterm><primary>-XNoImplicitPrelude
- option</primary></indexterm> GHC normally imports
- <filename>Prelude.hi</filename> files for you. If you'd
- rather it didn't, then give it a
- <option>-XNoImplicitPrelude</option> option. The idea is
- that you can then import a Prelude of your own. (But don't
- call it <literal>Prelude</literal>; the Haskell module
- namespace is flat, and you must not conflict with any
- Prelude module.)</para>
-
- <para>Even though you have not imported the Prelude, most of
- the built-in syntax still refers to the built-in Haskell
- Prelude types and values, as specified by the Haskell
- Report. For example, the type <literal>[Int]</literal>
- still means <literal>Prelude.[] Int</literal>; tuples
- continue to refer to the standard Prelude tuples; the
- translation for list comprehensions continues to use
- <literal>Prelude.map</literal> etc.</para>
-
- <para>However, <option>-XNoImplicitPrelude</option> does
- change the handling of certain built-in syntax: see <xref
- linkend="rebindable-syntax"/>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>-XImplicitParams</option></term>
- <listitem>
- <para>Enables implicit parameters (see <xref
- linkend="implicit-parameters"/>). Currently also implied by
- <option>-fglasgow-exts</option>.</para>
-
- <para>Syntax stolen:
- <literal>?<replaceable>varid</replaceable></literal>,
- <literal>%<replaceable>varid</replaceable></literal>.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><option>-XOverloadedStrings</option></term>
- <listitem>
- <para>Enables overloaded string literals (see <xref
- linkend="overloaded-strings"/>).</para>
- </listitem>
- </varlistentry>
+ is equivalent to enabling the following extensions:
+ <option>-XPrintExplicitForalls</option>,
+ <option>-XForeignFunctionInterface</option>,
+ <option>-XUnliftedFFITypes</option>,
+ <option>-XGADTs</option>,
+ <option>-XImplicitParams</option>,
+ <option>-XScopedTypeVariables</option>,
+ <option>-XUnboxedTuples</option>,
+ <option>-XTypeSynonymInstances</option>,
+ <option>-XStandaloneDeriving</option>,
+ <option>-XDeriveDataTypeable</option>,
+ <option>-XFlexibleContexts</option>,
+ <option>-XFlexibleInstances</option>,
+ <option>-XConstrainedClassMethods</option>,
+ <option>-XMultiParamTypeClasses</option>,
+ <option>-XFunctionalDependencies</option>,
+ <option>-XMagicHash</option>,
+ <option>-XPolymorphicComponents</option>,
+ <option>-XExistentialQuantification</option>,
+ <option>-XUnicodeSyntax</option>,
+ <option>-XPostfixOperators</option>,
+ <option>-XPatternGuards</option>,
+ <option>-XLiberalTypeSynonyms</option>,
+ <option>-XRankNTypes</option>,
+ <option>-XImpredicativeTypes</option>,
+ <option>-XTypeOperators</option>,
+ <option>-XRecursiveDo</option>,
+ <option>-XParallelListComp</option>,
+ <option>-XEmptyDataDecls</option>,
+ <option>-XKindSignatures</option>,
+ <option>-XGeneralizedNewtypeDeriving</option>,
+ <option>-XTypeFamilies</option>.
+ Enabling these options is the <emphasis>only</emphasis>
+ effect of <option>-fglasgow-exts</option>.
+ We are trying to move away from this portmanteau flag,
+ and towards enabling features individually.</para>