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<article id="visual-haskell">

  <articleinfo>

    <title>Visual Haskell User's Guide</title>
  <author>
    <firstname>Simon</firstname>
    <surname>Marlow</surname>
    <email>simonmar@microsoft.com</email>
  </author>
  <author>
    <firstname>Krasimir</firstname>
    <surname>Angelov</surname>
    <email>kr.angelov@gmail.com</email>
  </author>

  </articleinfo>

  <section id="sec-introduction">
    <title>Introduction</title>

    <para>Visual Haskell is a plugin for Microsoft's Visual Studio
      development environment to support development of Haskell software.
      Like the other Visual languages, Visual Haskell integrates with the
      Visual Studio editor to provide interactive features to aid Haskell
      development, and it enables the construction of projects consisting of
      multiple Haskell modules.</para>

    <section id="sec-obtaining">
      <title>Installing Visual Haskell</title>

      <para>In order to use Visual Haskell, you need <ulink url="http://msdn.microsoft.com/vstudio/productinfo/">Visual Studio .NET
        2003</ulink>.  Right now, this is the only supported version of Visual
        Studio - unfortunately we haven't yet added support for the 2005
        Beta.  The Express languages (Visual C++ Express etc.) also will not
        work, because they don't have support for plugins.</para>

      <para>You don't need to install GHC separately: Visual Haskell
        is bundled with a complete GHC distribution, and various other tools
        (Happy, Alex, Haddock).</para>

      <para>The latest Visual Haskell installer can be obtained from
        here:</para>

      <para><ulink
        url="http://www.haskell.org/visualhaskell/"><literal>http://www.haskell.org/visualhaskell/</literal></ulink></para>
    </section>

    <section id="release-notes">
      <title>Release Notes</title>

      <section>
        <title>Version 0.0, first release</title>

        <para>This release is a technology preview, and should be considered
          alpha quality.  It works for us, but you are fairly likely to
          encounter problems.  If you're willing to try it out and report
          bugs, we'd be grateful for the feedback.</para>

        <itemizedlist>
          <listitem>
            <para>This release of Visual Haskell is bundled with a
              development snapshot of GHC, version 6.5 from around 14
              September 2005.  This version of GHC is used to provide the
              interactive editing features, and will be used to compile all
              code inside Visual Haskell.  It is possible that in future
              releases we may be able to relax this tight coupling between
              Visual Haskell and the bundled GHC.</para>

            <para>Please note that future releases of Visual
              Haskell will update the compiler, and hence the
              packages, and so may break your code.  Also note that because
              the bundled GHC is not a released version, it may have bugs and
              quirks itself: please report them as usual to
              <email>glasgow-haskell-bugs@haskell.org</email>.</para>
        </listitem>

        <listitem>
          <para>We're not making source code for the plugin generally
            available at this time, due to licensing restrictions on the
            Visual Studio APIs that the plugin uses (for more
            information see <ulink
              url="http://msdn.microsoft.com/vstudio/extend/">Visual Studio
              Extensibility Center</ulink>).  If you're interested in
            contributing to Visual Haskell, please get in touch with the
            authors.</para>
        </listitem>
      </itemizedlist>
    </section>
  </section>

    <section id="sec-bugs">
      <title>Getting support, reporting bugs</title>
      <para>Please report bugs to
        <email>glasgow-haskell-bugs@haskell.org</email> (subscribe <ulink url="http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs">here</ulink>), clearly indicating
        that your bug report relates to Visual Haskell, and giving as much
        information as possible so that we can reproduce the bug.  Even if
        you can't reproduce the bug reliably, it is still useful to report
        what you've seen.</para>

      <para>For help and support, use the
        <email>glasgow-haskell-users@haskell.org</email> (subscribe <ulink
          url="http://www.haskell.org/mailman/listinfo/glasgow-haskell-users">here</ulink>) mailing list.</para>
    </section>

    <section id="sec-license">
      <title>License</title>

    <blockquote>
      <para>Copyright © Microsoft Corporation. All rights reserved.</para>
      <para>Copyright © The University of Glasgow. All rights reserved.</para>
      <para>Copyright © Krasimir Angelov. All rights reserved.</para>

      <para>Redistribution and use in source and binary forms, with or without
        modification,  are permitted provided that the following conditions
        are met:</para>

      <itemizedlist>
        <listitem>
          <para>Redistributions of source code must retain the above
            copyright notice, this list of conditions and the following
            disclaimer.</para>
        </listitem>

        <listitem>
          <para>Redistributions in binary form must reproduce the above
            copyright notice, this list of conditions and the following
            disclaimer in the documentation and/or other materials provided
            with the distribution.</para>
        </listitem>

        <listitem>
          <para>The names of the copyright holders may not be used to endorse
            or promote products derived from this software without specific
            prior written permission.</para>
        </listitem>
      </itemizedlist>

      <para>THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
        "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
        LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
        FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
        COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
        SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
        LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
        USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
        AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
        ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
        POSSIBILITY OF SUCH DAMAGE.</para>
    </blockquote>
  </section>

  </section>

  <section id="sec-using">
    <title>Using Visual Haskell</title>

    <section>
      <title>Overview of features</title>

      <para>The following features are provided in the Visual Studio editor
        when editing Haskell code:</para>

      <itemizedlist>
        <listitem>
          <para>Automatic checking of code as you type, and visual indication
            of parse errors, scoping errors and type errors.</para>
        </listitem>

        <listitem>
        <para>Quick info: hovering the mouse over an identifier pops up
          an information box, including the type of the identifier.</para>
        </listitem>

        <listitem>
        <para>A drop-down bar at the top of the editing window lists the
          top-level declarations in the module, and allows quick navigation
          to a declaration.</para>
        </listitem>

        <listitem>
        <para>Name completion for identifiers in scope: press Ctrl+Space
          after a partial identifier to see the completions.</para>
        </listitem>

        <listitem>
        <para>Go to declaration: right clicking on an identifier and
          selecting "Go to declaration" will jump the cursor to the
          declaration of the identifier.  This works for locally-defined
          identifiers and those defined in another module of the project; it
          does not work for library functions currently.</para>
        </listitem>
      </itemizedlist>

    <para>The following features are provided by the project system for
      constructing Haskell projects:</para>

    <itemizedlist>
      <listitem>
        <para>Multi-module Haskell projects are fully supported, based on the
          <ulink url="http://www.haskell.org/cabal">Cabal</ulink>
          infrastructure.  A project in Visual Haskell <emphasis>is</emphasis>
          a Cabal package, and vice-versa.  A Visual Studio project can be
          taken to a machine without Visual Haskell and built/installed as a
          normal Cabal package, and an existing Cabal package can be edited
          directly in Visual Haskell<footnote><para>This works as long as the
              Cabal package is using Cabal's simple build system; Cabal
              packages using their own build systems cannot be edited in Visual
              Haskell.</para>
          </footnote>.</para>
      </listitem>

      <listitem>
        <para>Editing of most of the package meta-data is supported through
          the project property pages.</para>
      </listitem>

      <listitem>
        <para>The interactive editing features work across multiple modules in
          a project.  When one module is edited, changes are automatically
          propagated to dependent modules, even if the edited module has not yet
          been saved.</para>
      </listitem>

      <listitem>
        <para>Building is supported through the Cabal build system, and build
          errors are communicated back to the editor and placed in the task
          list.  Use any of the Visual Studio build commands (e.g. Build
          Project from the context menu on the project, or Ctrl-Shift-B to
          build the whole solution).</para>
      </listitem>

    </itemizedlist>

  <para>Additionally, Visual Haskell is bundled with a large collection of
    documentation: the GHC manual, the hierarchical libraries reference, and
    other material all of which can be browsed within Visual Studio
    itself.</para>
  </section>

  <section>
    <title>Getting Started</title>

    <para>After installing Visual Haskell, start up Visual Studio as you
      would normally, and observe that on the splash screen where it lists
      the supported languages you should now see an icon for Visual
      Haskell (if you don't see this, something has gone wrong... please let
      us know).</para>

    <para>Firstly, take a look at the bundled documentation.  Go to
      Help-&gt;Contents, and you should see the &ldquo;Visual Haskell Help
      Collection&rdquo;, which contains a large collection of GHC and
      Haskell-related documentaiton, including this document.</para>

    <para>To start using Visual Haskell right away, create a new
      project (File-&gt;New-&gt;Project...).  Select one of the Haskell
      project types (Console Application or Library Package), and hit Ok.
      The project will be created for you, and an example module
      added: <literal>Main.hs</literal> for an application, or
      <literal>Module1.hs</literal> for a library.</para>

    <para>You can now start adding code to
      <literal>Main.hs</literal>, or adding new modules.  To add a new
      module, right-click on the <literal>src</literal> directory, and
      select Add-&gt;New Item.  Visual Haskell supports hierarchical
      modules too: you can add new folders using the same Add menu to
      create new nodes in the hierarchy.</para>

    <para>If you have any errors in your code, they will be underlined with
      a red squiggly line.  Select the Tasks window (usually a tab near the
      bottom of the Visual Studio window) to see the error messages, and
      click on an error message to jump to it in the editor.</para>

    <para>To build the program, hit Ctrl-Shift-B, or select one of the
      options from the Build menu.</para>
  </section>

  <section>
    <title>Editing Haskell code</title>

      <para>(ToDo: more detail here)</para>

      <para>Your module must be plain Haskell (<literal>.hs</literal>) for
        the interactive features to fully work.  If your module is
        pre-processed with CPP or Literate Haskell, then Visual Haskell will
        only check the module when it is saved; between saves the source will
        not be checked for errors and the type information will not be
        updated.  If the source file is
        pre-processed with Happy or another pre-processor, then you may have
        to build the project before the type information will be updated
        (because the pre-processor is only run as part of the build process).
        Pre-processed source files work fine in a multi-module setting; you
        can have modules which depend on a pre-processed module and full
        interactive checking will still be available in those modules.</para>

      <para>Because Visual Haskell is using GHC as a backend for its
        interactive editing features, it supports the full GHC language,
        including all extensions.</para>
    </section>

    <section>
      <title>Using Projects</title>
      <para>(ToDo: more detail here)</para>
    </section>

  </section>
</article>
