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<title>Graphics/UI/GLUT/Menu.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# OPTIONS_GHC -fno-cse #-}</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-4"></a><span class='hs-comment'>-- |</span>
<a name="line-5"></a><span class='hs-comment'>-- Module : Graphics.UI.GLUT.Menu</span>
<a name="line-6"></a><span class='hs-comment'>-- Copyright : (c) Sven Panne 2002-2005</span>
<a name="line-7"></a><span class='hs-comment'>-- License : BSD-style (see the file libraries/GLUT/LICENSE)</span>
<a name="line-8"></a><span class='hs-comment'>--</span>
<a name="line-9"></a><span class='hs-comment'>-- Maintainer : sven.panne@aedion.de</span>
<a name="line-10"></a><span class='hs-comment'>-- Stability : stable</span>
<a name="line-11"></a><span class='hs-comment'>-- Portability : portable</span>
<a name="line-12"></a><span class='hs-comment'>--</span>
<a name="line-13"></a><span class='hs-comment'>-- GLUT supports simple cascading pop-up menus. They are designed to let a user</span>
<a name="line-14"></a><span class='hs-comment'>-- select various modes within a program. The functionality is simple and</span>
<a name="line-15"></a><span class='hs-comment'>-- minimalistic and is meant to be that way. Do not mistake GLUT\'s pop-up menu</span>
<a name="line-16"></a><span class='hs-comment'>-- facility with an attempt to create a full-featured user interface.</span>
<a name="line-17"></a><span class='hs-comment'>--</span>
<a name="line-18"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-19"></a>
<a name="line-20"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Menu</span> <span class='hs-layout'>(</span>
<a name="line-21"></a> <span class='hs-conid'>Menu</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>MenuItem</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>MenuCallback</span><span class='hs-layout'>,</span> <span class='hs-varid'>attachMenu</span><span class='hs-layout'>,</span>
<a name="line-22"></a> <span class='hs-varid'>numMenuItems</span>
<a name="line-23"></a><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-24"></a>
<a name="line-25"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Array</span> <span class='hs-layout'>(</span> <span class='hs-varid'>listArray</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'>!</span><span class='hs-layout'>)</span> <span class='hs-layout'>)</span>
<a name="line-26"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>IORef</span> <span class='hs-layout'>(</span> <span class='hs-conid'>IORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>newIORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>readIORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>modifyIORef</span> <span class='hs-layout'>)</span>
<a name="line-27"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>Map</span> <span class='hs-layout'>(</span> <span class='hs-varid'>empty</span><span class='hs-layout'>,</span> <span class='hs-varid'>lookup</span><span class='hs-layout'>,</span> <span class='hs-varid'>insert</span><span class='hs-layout'>,</span> <span class='hs-varid'>delete</span> <span class='hs-layout'>)</span>
<a name="line-28"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Map</span> <span class='hs-layout'>)</span>
<a name="line-29"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>C</span><span class='hs-varop'>.</span><span class='hs-conid'>String</span> <span class='hs-layout'>(</span> <span class='hs-conid'>CString</span><span class='hs-layout'>,</span> <span class='hs-varid'>withCString</span> <span class='hs-layout'>)</span>
<a name="line-30"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>C</span><span class='hs-varop'>.</span><span class='hs-conid'>Types</span> <span class='hs-layout'>(</span> <span class='hs-conid'>CInt</span> <span class='hs-layout'>)</span>
<a name="line-31"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Ptr</span> <span class='hs-layout'>(</span> <span class='hs-conid'>FunPtr</span><span class='hs-layout'>,</span> <span class='hs-varid'>freeHaskellFunPtr</span> <span class='hs-layout'>)</span>
<a name="line-32"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span> <span class='hs-varid'>unless</span><span class='hs-layout'>,</span> <span class='hs-varid'>zipWithM</span><span class='hs-layout'>,</span> <span class='hs-varid'>when</span> <span class='hs-layout'>)</span>
<a name="line-33"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span> <span class='hs-layout'>(</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-layout'>)</span>
<a name="line-34"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>Rendering</span><span class='hs-varop'>.</span><span class='hs-conid'>OpenGL</span><span class='hs-varop'>.</span><span class='hs-conid'>GL</span><span class='hs-varop'>.</span><span class='hs-conid'>StateVar</span> <span class='hs-layout'>(</span>
<a name="line-35"></a> <span class='hs-conid'>HasGetter</span><span class='hs-layout'>(</span><span class='hs-varid'>get</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>HasSetter</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>$=</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-conid'>GettableStateVar</span><span class='hs-layout'>,</span> <span class='hs-varid'>makeGettableStateVar</span><span class='hs-layout'>,</span>
<a name="line-37"></a> <span class='hs-conid'>StateVar</span><span class='hs-layout'>,</span> <span class='hs-varid'>makeStateVar</span> <span class='hs-layout'>)</span>
<a name="line-38"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Constants</span> <span class='hs-layout'>(</span> <span class='hs-varid'>glut_MENU_NUM_ITEMS</span> <span class='hs-layout'>)</span>
<a name="line-39"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>QueryUtils</span> <span class='hs-layout'>(</span> <span class='hs-varid'>simpleGet</span> <span class='hs-layout'>)</span>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Types</span> <span class='hs-layout'>(</span> <span class='hs-varid'>marshalMouseButton</span> <span class='hs-layout'>)</span>
<a name="line-41"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Window</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Window</span> <span class='hs-layout'>)</span>
<a name="line-42"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Callbacks</span><span class='hs-varop'>.</span><span class='hs-conid'>Registration</span> <span class='hs-layout'>(</span> <span class='hs-varid'>getCurrentWindow</span> <span class='hs-layout'>)</span>
<a name="line-43"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Graphics</span><span class='hs-varop'>.</span><span class='hs-conid'>UI</span><span class='hs-varop'>.</span><span class='hs-conid'>GLUT</span><span class='hs-varop'>.</span><span class='hs-conid'>Callbacks</span><span class='hs-varop'>.</span><span class='hs-conid'>Window</span> <span class='hs-layout'>(</span> <span class='hs-conid'>MouseButton</span> <span class='hs-layout'>)</span>
<a name="line-44"></a>
<a name="line-45"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-46"></a>
<a name="line-47"></a><a name="Menu"></a><span class='hs-comment'>-- | A menu is simply a list of menu items.</span>
<a name="line-48"></a><a name="Menu"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Menu</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Menu</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>MenuItem</span><span class='hs-keyglyph'>]</span>
<a name="line-49"></a>
<a name="line-50"></a><a name="MenuItem"></a><span class='hs-comment'>-- | A single item within a menu can either be a plain menu entry or a sub-menu</span>
<a name="line-51"></a><a name="MenuItem"></a><span class='hs-comment'>-- entry, allowing for arbitrarily deep nested menus.</span>
<a name="line-52"></a><a name="MenuItem"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>MenuItem</span>
<a name="line-53"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>MenuEntry</span> <span class='hs-conid'>String</span> <span class='hs-conid'>MenuCallback</span> <span class='hs-comment'>-- ^ A plain menu entry with an associated</span>
<a name="line-54"></a> <span class='hs-comment'>-- callback, which is triggered when the</span>
<a name="line-55"></a> <span class='hs-comment'>-- user selects the entry</span>
<a name="line-56"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>SubMenu</span> <span class='hs-conid'>String</span> <span class='hs-conid'>Menu</span> <span class='hs-comment'>-- ^ A sub-menu, which is cascaded when the</span>
<a name="line-57"></a> <span class='hs-comment'>-- user selects the entry, allowing</span>
<a name="line-58"></a> <span class='hs-comment'>-- sub-menu entries to be selected</span>
<a name="line-59"></a>
<a name="line-60"></a><a name="MenuCallback"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>MenuCallback</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-61"></a>
<a name="line-62"></a><span class='hs-comment'>-- | Create a new pop-up menu for the /current window,/ attaching it to the</span>
<a name="line-63"></a><span class='hs-comment'>-- given mouse button. A previously attached menu (if any), is detached before</span>
<a name="line-64"></a><span class='hs-comment'>-- and won\'t receive callbacks anymore.</span>
<a name="line-65"></a><span class='hs-comment'>--</span>
<a name="line-66"></a><span class='hs-comment'>-- It is illegal to call 'attachMenu' while any (sub-)menu is in use, i.e.</span>
<a name="line-67"></a><span class='hs-comment'>-- popped up.</span>
<a name="line-68"></a><span class='hs-comment'>--</span>
<a name="line-69"></a><span class='hs-comment'>-- /X Implementation Notes:/ If available, GLUT for X will take advantage of</span>
<a name="line-70"></a><span class='hs-comment'>-- overlay planes for implementing pop-up menus. The use of overlay planes can</span>
<a name="line-71"></a><span class='hs-comment'>-- eliminate display callbacks when pop-up menus are deactivated. The</span>
<a name="line-72"></a><span class='hs-comment'>-- @SERVER_OVERLAY_VISUALS@ convention is used to determine if overlay visuals</span>
<a name="line-73"></a><span class='hs-comment'>-- are available.</span>
<a name="line-74"></a>
<a name="line-75"></a><a name="attachMenu"></a><span class='hs-definition'>attachMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MouseButton</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Menu</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-76"></a><span class='hs-definition'>attachMenu</span> <span class='hs-varid'>mouseButton</span> <span class='hs-varid'>menu</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Menu</span> <span class='hs-varid'>items</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-77"></a> <span class='hs-varid'>win</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getCurrentWindow</span> <span class='hs-str'>"attachMenu"</span>
<a name="line-78"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>hook</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>MenuHook</span> <span class='hs-varid'>win</span> <span class='hs-varid'>mouseButton</span>
<a name="line-79"></a> <span class='hs-varid'>detachMenu</span> <span class='hs-varid'>hook</span>
<a name="line-80"></a> <span class='hs-varid'>unless</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-varid'>items</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-81"></a> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>destructor</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>traverseMenu</span> <span class='hs-varid'>menu</span>
<a name="line-82"></a> <span class='hs-varid'>addToMenuTable</span> <span class='hs-varid'>hook</span> <span class='hs-varid'>destructor</span>
<a name="line-83"></a> <span class='hs-varid'>attachMenu_</span> <span class='hs-varid'>mouseButton</span>
<a name="line-84"></a>
<a name="line-85"></a><a name="detachMenu"></a><span class='hs-definition'>detachMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuHook</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-86"></a><span class='hs-definition'>detachMenu</span> <span class='hs-varid'>hook</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>MenuHook</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>mouseButton</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-87"></a> <span class='hs-varid'>maybeDestructor</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>lookupInMenuTable</span> <span class='hs-varid'>hook</span>
<a name="line-88"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>maybeDestructor</span> <span class='hs-keyword'>of</span>
<a name="line-89"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-90"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>destructor</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-varid'>detachMenu_</span> <span class='hs-varid'>mouseButton</span>
<a name="line-91"></a> <span class='hs-varid'>destructor</span>
<a name="line-92"></a> <span class='hs-varid'>deleteFromMenuTable</span> <span class='hs-varid'>hook</span>
<a name="line-93"></a>
<a name="line-94"></a><a name="traverseMenu"></a><span class='hs-definition'>traverseMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Menu</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>MenuID</span><span class='hs-layout'>,</span> <span class='hs-conid'>Destructor</span><span class='hs-layout'>)</span>
<a name="line-95"></a><span class='hs-definition'>traverseMenu</span> <span class='hs-layout'>(</span><span class='hs-conid'>Menu</span> <span class='hs-varid'>items</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-96"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>callbackArray</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>listArray</span> <span class='hs-layout'>(</span><span class='hs-num'>1</span><span class='hs-layout'>,</span> <span class='hs-varid'>length</span> <span class='hs-varid'>items</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>makeCallback</span> <span class='hs-varid'>items</span><span class='hs-layout'>)</span>
<a name="line-97"></a> <span class='hs-varid'>cb</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>makeMenuFunc</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>i</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>callbackArray</span> <span class='hs-varop'>!</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromIntegral</span> <span class='hs-varid'>i</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-98"></a> <span class='hs-varid'>menuID</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>glutCreateMenu</span> <span class='hs-varid'>cb</span>
<a name="line-99"></a> <span class='hs-varid'>destructors</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zipWithM</span> <span class='hs-varid'>addMenuItem</span> <span class='hs-varid'>items</span> <span class='hs-keyglyph'>[</span><span class='hs-num'>1</span><span class='hs-keyglyph'>..</span><span class='hs-keyglyph'>]</span>
<a name="line-100"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>destructor</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>sequence_</span> <span class='hs-varid'>destructors</span>
<a name="line-101"></a> <span class='hs-varid'>glutDestroyMenu</span> <span class='hs-varid'>menuID</span>
<a name="line-102"></a> <span class='hs-varid'>freeHaskellFunPtr</span> <span class='hs-varid'>cb</span>
<a name="line-103"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>menuID</span><span class='hs-layout'>,</span> <span class='hs-varid'>destructor</span><span class='hs-layout'>)</span>
<a name="line-104"></a>
<a name="line-105"></a><a name="makeCallback"></a><span class='hs-definition'>makeCallback</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuItem</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>MenuCallback</span>
<a name="line-106"></a><span class='hs-definition'>makeCallback</span> <span class='hs-layout'>(</span><span class='hs-conid'>MenuEntry</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>cb</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cb</span>
<a name="line-107"></a><span class='hs-definition'>makeCallback</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"shouldn't receive a callback for submenus"</span>
<a name="line-108"></a>
<a name="line-109"></a><a name="addMenuItem"></a><span class='hs-definition'>addMenuItem</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuItem</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Value</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Destructor</span>
<a name="line-110"></a><span class='hs-definition'>addMenuItem</span> <span class='hs-layout'>(</span><span class='hs-conid'>MenuEntry</span> <span class='hs-varid'>s</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-111"></a> <span class='hs-varid'>addMenuEntry</span> <span class='hs-varid'>s</span> <span class='hs-varid'>v</span>
<a name="line-112"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>glutRemoveMenuItem</span> <span class='hs-num'>1</span>
<a name="line-113"></a><span class='hs-definition'>addMenuItem</span> <span class='hs-layout'>(</span><span class='hs-conid'>SubMenu</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-114"></a> <span class='hs-layout'>(</span><span class='hs-varid'>menuID</span><span class='hs-layout'>,</span> <span class='hs-varid'>destructor</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>saveExcursion</span> <span class='hs-layout'>(</span><span class='hs-varid'>traverseMenu</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-115"></a> <span class='hs-varid'>addSubMenu</span> <span class='hs-varid'>s</span> <span class='hs-varid'>menuID</span>
<a name="line-116"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>glutRemoveMenuItem</span> <span class='hs-num'>1</span>
<a name="line-117"></a> <span class='hs-varid'>destructor</span>
<a name="line-118"></a>
<a name="line-119"></a><a name="saveExcursion"></a><span class='hs-comment'>-- Perform an action, saving/restoring the current menu around it</span>
<a name="line-120"></a><span class='hs-definition'>saveExcursion</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span>
<a name="line-121"></a><span class='hs-definition'>saveExcursion</span> <span class='hs-varid'>act</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-122"></a> <span class='hs-varid'>menuID</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get</span> <span class='hs-varid'>currentMenu</span>
<a name="line-123"></a> <span class='hs-varid'>returnValue</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>act</span>
<a name="line-124"></a> <span class='hs-varid'>when</span> <span class='hs-layout'>(</span><span class='hs-varid'>isRealMenu</span> <span class='hs-varid'>menuID</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-125"></a> <span class='hs-varid'>currentMenu</span> <span class='hs-varop'>$=</span> <span class='hs-varid'>menuID</span>
<a name="line-126"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>returnValue</span>
<a name="line-127"></a>
<a name="line-128"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-129"></a><span class='hs-comment'>-- This seems to be a common Haskell hack nowadays: A plain old global variable</span>
<a name="line-130"></a><span class='hs-comment'>-- with an associated mutator. Perhaps some language/library support is needed?</span>
<a name="line-131"></a>
<a name="line-132"></a><a name="theMenuTable"></a><span class='hs-comment'>{-# NOINLINE theMenuTable #-}</span>
<a name="line-133"></a><span class='hs-definition'>theMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IORef</span> <span class='hs-conid'>MenuTable</span>
<a name="line-134"></a><span class='hs-definition'>theMenuTable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-layout'>(</span><span class='hs-varid'>newIORef</span> <span class='hs-varid'>emptyMenuTable</span><span class='hs-layout'>)</span>
<a name="line-135"></a>
<a name="line-136"></a><a name="getMenuTable"></a><span class='hs-definition'>getMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>MenuTable</span>
<a name="line-137"></a><span class='hs-definition'>getMenuTable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>readIORef</span> <span class='hs-varid'>theMenuTable</span>
<a name="line-138"></a>
<a name="line-139"></a><a name="modifyMenuTable"></a><span class='hs-definition'>modifyMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>MenuTable</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>MenuTable</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-140"></a><span class='hs-definition'>modifyMenuTable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>modifyIORef</span> <span class='hs-varid'>theMenuTable</span>
<a name="line-141"></a>
<a name="line-142"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-143"></a><span class='hs-comment'>-- To facilitate cleanup, we have to keep track how to destroy menus which are</span>
<a name="line-144"></a><span class='hs-comment'>-- currently attached in a window to a mouse button.</span>
<a name="line-145"></a>
<a name="line-146"></a><a name="MenuHook"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>MenuHook</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>MenuHook</span> <span class='hs-conid'>Window</span> <span class='hs-conid'>MouseButton</span>
<a name="line-147"></a> <span class='hs-keyword'>deriving</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Eq</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-layout'>)</span>
<a name="line-148"></a>
<a name="line-149"></a><a name="Destructor"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Destructor</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-150"></a>
<a name="line-151"></a><a name="MenuTable"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>MenuTable</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span> <span class='hs-conid'>MenuHook</span> <span class='hs-conid'>Destructor</span>
<a name="line-152"></a>
<a name="line-153"></a><a name="emptyMenuTable"></a><span class='hs-definition'>emptyMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuTable</span>
<a name="line-154"></a><span class='hs-definition'>emptyMenuTable</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-155"></a>
<a name="line-156"></a><a name="lookupInMenuTable"></a><span class='hs-definition'>lookupInMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuHook</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-conid'>Destructor</span><span class='hs-layout'>)</span>
<a name="line-157"></a><span class='hs-definition'>lookupInMenuTable</span> <span class='hs-varid'>callbackID</span> <span class='hs-keyglyph'>=</span>
<a name="line-158"></a> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>callbackID</span><span class='hs-layout'>)</span> <span class='hs-varid'>getMenuTable</span>
<a name="line-159"></a>
<a name="line-160"></a><a name="deleteFromMenuTable"></a><span class='hs-definition'>deleteFromMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuHook</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-161"></a><span class='hs-definition'>deleteFromMenuTable</span> <span class='hs-varid'>callbackID</span> <span class='hs-keyglyph'>=</span>
<a name="line-162"></a> <span class='hs-varid'>modifyMenuTable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>delete</span> <span class='hs-varid'>callbackID</span><span class='hs-layout'>)</span>
<a name="line-163"></a>
<a name="line-164"></a><a name="addToMenuTable"></a><span class='hs-definition'>addToMenuTable</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuHook</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Destructor</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-165"></a><span class='hs-definition'>addToMenuTable</span> <span class='hs-varid'>callbackID</span> <span class='hs-varid'>funPtr</span> <span class='hs-keyglyph'>=</span>
<a name="line-166"></a> <span class='hs-varid'>modifyMenuTable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-varid'>callbackID</span> <span class='hs-varid'>funPtr</span><span class='hs-layout'>)</span>
<a name="line-167"></a>
<a name="line-168"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-169"></a>
<a name="line-170"></a><a name="MenuID"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CInt</span>
<a name="line-171"></a><a name="Value"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Value</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CInt</span>
<a name="line-172"></a><a name="Item"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Item</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CInt</span>
<a name="line-173"></a>
<a name="line-174"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-175"></a>
<a name="line-176"></a><span class='hs-comment'>-- | The type of a menu callback action that is called when a menu entry from a</span>
<a name="line-177"></a><span class='hs-comment'>-- menu is selected. The value passed to the callback is determined by the value</span>
<a name="line-178"></a><span class='hs-comment'>-- for the selected menu entry.</span>
<a name="line-179"></a>
<a name="line-180"></a><a name="MenuCB"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>MenuCB</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>CInt</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-181"></a>
<a name="line-182"></a><span class='hs-comment'>-- | Create a new pop-up menu and return a unique identifier for it, which can</span>
<a name="line-183"></a><span class='hs-comment'>-- be used when setting 'currentMenu'. Implicitly, the /current menu/ is set to</span>
<a name="line-184"></a><span class='hs-comment'>-- the newly created menu.</span>
<a name="line-185"></a><span class='hs-comment'>--</span>
<a name="line-186"></a><span class='hs-comment'>-- When the menu callback is called because a menu entry is selected for the</span>
<a name="line-187"></a><span class='hs-comment'>-- menu, the /current menu/ will be implicitly set to the menu with the selected</span>
<a name="line-188"></a><span class='hs-comment'>-- entry before the callback is made.</span>
<a name="line-189"></a><span class='hs-comment'>--</span>
<a name="line-190"></a><span class='hs-comment'>-- /X Implementation Notes:/ If available, GLUT for X will take advantage of</span>
<a name="line-191"></a><span class='hs-comment'>-- overlay planes for implementing pop-up menus. The use of overlay planes can</span>
<a name="line-192"></a><span class='hs-comment'>-- eliminate display callbacks when pop-up menus are deactivated. The</span>
<a name="line-193"></a><span class='hs-comment'>-- @SERVER_OVERLAY_VISUALS@ convention is used to determine if overlay visuals</span>
<a name="line-194"></a><span class='hs-comment'>-- are available.</span>
<a name="line-195"></a>
<a name="line-196"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutCreateMenu"</span> <span class='hs-varid'>glutCreateMenu</span> <span class='hs-keyglyph'>::</span>
<a name="line-197"></a> <span class='hs-conid'>FunPtr</span> <span class='hs-conid'>MenuCB</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>MenuID</span>
<a name="line-198"></a>
<a name="line-199"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-keyword'>ccall</span> <span class='hs-str'>"wrapper"</span> <span class='hs-varid'>makeMenuFunc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuCB</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>FunPtr</span> <span class='hs-conid'>MenuCB</span><span class='hs-layout'>)</span>
<a name="line-200"></a>
<a name="line-201"></a><span class='hs-comment'>-- | Destroy the specified menu. If it was the /current menu/, the /current</span>
<a name="line-202"></a><span class='hs-comment'>-- menu/ becomes invalid and 'currentMenu' will contain 'Nothing'.</span>
<a name="line-203"></a>
<a name="line-204"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutDestroyMenu"</span> <span class='hs-varid'>glutDestroyMenu</span> <span class='hs-keyglyph'>::</span>
<a name="line-205"></a> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-206"></a>
<a name="line-207"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-208"></a>
<a name="line-209"></a><span class='hs-comment'>-- | Controls the /current menu./ If no menus exist or the previous /current</span>
<a name="line-210"></a><span class='hs-comment'>-- menu/ was destroyed, a pseudo menu is returned, see 'isRealMenu'.</span>
<a name="line-211"></a>
<a name="line-212"></a><a name="currentMenu"></a><span class='hs-definition'>currentMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>StateVar</span> <span class='hs-conid'>MenuID</span>
<a name="line-213"></a><span class='hs-definition'>currentMenu</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeStateVar</span> <span class='hs-varid'>glutGetMenu</span> <span class='hs-varid'>glutSetMenu</span>
<a name="line-214"></a>
<a name="line-215"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutSetMenu"</span> <span class='hs-varid'>glutSetMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-216"></a>
<a name="line-217"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutGetMenu"</span> <span class='hs-varid'>glutGetMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>MenuID</span>
<a name="line-218"></a>
<a name="line-219"></a><span class='hs-comment'>-- | Returns 'True' if the given menu identifier refers to a real menu, not</span>
<a name="line-220"></a><span class='hs-comment'>-- a pseudo one.</span>
<a name="line-221"></a>
<a name="line-222"></a><a name="isRealMenu"></a><span class='hs-definition'>isRealMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-223"></a><span class='hs-definition'>isRealMenu</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varop'>/=</span> <span class='hs-num'>0</span><span class='hs-layout'>)</span>
<a name="line-224"></a>
<a name="line-225"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-226"></a>
<a name="line-227"></a><span class='hs-comment'>-- | Add a menu entry to the bottom of the /current menu./ The given string will</span>
<a name="line-228"></a><span class='hs-comment'>-- be displayed for the newly added menu entry. If the menu entry is selected by</span>
<a name="line-229"></a><span class='hs-comment'>-- the user, the menu\'s callback will be called passing the given value as the</span>
<a name="line-230"></a><span class='hs-comment'>-- callback\'s parameter.</span>
<a name="line-231"></a>
<a name="line-232"></a><a name="addMenuEntry"></a><span class='hs-definition'>addMenuEntry</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Value</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-233"></a><span class='hs-definition'>addMenuEntry</span> <span class='hs-varid'>name</span> <span class='hs-varid'>value</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>withCString</span> <span class='hs-varid'>name</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>n</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>glutAddMenuEntry</span> <span class='hs-varid'>n</span> <span class='hs-varid'>value</span>
<a name="line-234"></a>
<a name="line-235"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutAddMenuEntry"</span> <span class='hs-varid'>glutAddMenuEntry</span> <span class='hs-keyglyph'>::</span>
<a name="line-236"></a> <span class='hs-conid'>CString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Value</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-237"></a>
<a name="line-238"></a><span class='hs-comment'>-- | Add a sub-menu trigger to the bottom of the /current menu./ The given</span>
<a name="line-239"></a><span class='hs-comment'>-- string will be displayed for the newly added sub-menu trigger. If the</span>
<a name="line-240"></a><span class='hs-comment'>-- sub-menu trigger is entered, the sub-menu specified by the given menu</span>
<a name="line-241"></a><span class='hs-comment'>-- identifier will be cascaded, allowing sub-menu menu items to be selected.</span>
<a name="line-242"></a>
<a name="line-243"></a><a name="addSubMenu"></a><span class='hs-definition'>addSubMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-244"></a><span class='hs-definition'>addSubMenu</span> <span class='hs-varid'>name</span> <span class='hs-varid'>menuID</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>withCString</span> <span class='hs-varid'>name</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>n</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>glutAddSubMenu</span> <span class='hs-varid'>n</span> <span class='hs-varid'>menuID</span>
<a name="line-245"></a>
<a name="line-246"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutAddSubMenu"</span> <span class='hs-varid'>glutAddSubMenu</span> <span class='hs-keyglyph'>::</span>
<a name="line-247"></a> <span class='hs-conid'>CString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>MenuID</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-248"></a>
<a name="line-249"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-250"></a>
<a name="line-251"></a><span class='hs-comment'>{- UNUSED
<a name="line-252"></a>-- | Change the specified menu entry in the /current menu/ into a menu entry.
<a name="line-253"></a>-- The given position determines which menu item should be changed and must be
<a name="line-254"></a>-- between 1 (the topmost menu item) and
<a name="line-255"></a>-- 'Graphics.UI.GLUT.State.getNumMenuItems' inclusive. The menu item to change
<a name="line-256"></a>-- does not have to be a menu entry already. The given string will be displayed
<a name="line-257"></a>-- for the newly changed menu entry. The given value will be returned to the
<a name="line-258"></a>-- menu\'s callback if this menu entry is selected.
<a name="line-259"></a>
<a name="line-260"></a>foreign import CALLCONV unsafe "glutChangeToMenuEntry" glutChangeToMenuEntry ::
<a name="line-261"></a> Item -> CString -> Value -> IO ()
<a name="line-262"></a>
<a name="line-263"></a>-- | Change the specified menu item in the /current menu/ into a sub-menu
<a name="line-264"></a>-- trigger. The given position determines which menu item should be changed and
<a name="line-265"></a>-- must be between 1 and 'Graphics.UI.GLUT.State.getNumMenuItems' inclusive. The
<a name="line-266"></a>-- menu item to change does not have to be a sub-menu trigger already. The
<a name="line-267"></a>-- given name will be displayed for the newly changed sub-menu trigger. The
<a name="line-268"></a>-- given menu identifier names the sub-menu to cascade from the newly added
<a name="line-269"></a>-- sub-menu trigger.
<a name="line-270"></a>
<a name="line-271"></a>foreign import CALLCONV unsafe "glutChangeToSubMenu" glutChangeToSubMenu ::
<a name="line-272"></a> Item -> CString -> MenuID -> IO ()
<a name="line-273"></a>-}</span>
<a name="line-274"></a>
<a name="line-275"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-276"></a>
<a name="line-277"></a><span class='hs-comment'>-- | Remove the menu item at the given position, regardless of whether it is a</span>
<a name="line-278"></a><span class='hs-comment'>-- menu entry or sub-menu trigger. The position must be between 1 (the topmost</span>
<a name="line-279"></a><span class='hs-comment'>-- menu item) and 'Graphics.UI.GLUT.State.getNumMenuItems' inclusive. Menu items</span>
<a name="line-280"></a><span class='hs-comment'>-- below the removed menu item are renumbered.</span>
<a name="line-281"></a>
<a name="line-282"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutRemoveMenuItem"</span> <span class='hs-varid'>glutRemoveMenuItem</span> <span class='hs-keyglyph'>::</span>
<a name="line-283"></a> <span class='hs-conid'>Item</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-284"></a>
<a name="line-285"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-286"></a>
<a name="line-287"></a><span class='hs-comment'>-- | Attach a mouse button for the /current window/ to the identifier of the</span>
<a name="line-288"></a><span class='hs-comment'>-- /current menu./ By attaching a menu identifier to a button, the named menu</span>
<a name="line-289"></a><span class='hs-comment'>-- will be popped up when the user presses the specified button. Note that the</span>
<a name="line-290"></a><span class='hs-comment'>-- menu is attached to the button by identifier, not by reference.</span>
<a name="line-291"></a>
<a name="line-292"></a>
<a name="line-293"></a><a name="attachMenu_"></a><span class='hs-definition'>attachMenu_</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MouseButton</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-294"></a><span class='hs-definition'>attachMenu_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>glutAttachMenu</span> <span class='hs-varop'>.</span> <span class='hs-varid'>marshalMouseButton</span>
<a name="line-295"></a>
<a name="line-296"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutAttachMenu"</span> <span class='hs-varid'>glutAttachMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>CInt</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-297"></a>
<a name="line-298"></a><span class='hs-comment'>-- | Detach an attached mouse button from the /current window./</span>
<a name="line-299"></a>
<a name="line-300"></a><a name="detachMenu_"></a><span class='hs-definition'>detachMenu_</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MouseButton</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-301"></a><span class='hs-definition'>detachMenu_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>glutDetachMenu</span> <span class='hs-varop'>.</span> <span class='hs-varid'>marshalMouseButton</span>
<a name="line-302"></a>
<a name="line-303"></a><span class='hs-keyword'>foreign</span> <span class='hs-keyword'>import</span> <span class='hs-conid'>CALLCONV</span> <span class='hs-keyword'>unsafe</span> <span class='hs-str'>"glutDetachMenu"</span> <span class='hs-varid'>glutDetachMenu</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>CInt</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-304"></a>
<a name="line-305"></a><span class='hs-comment'>--------------------------------------------------------------------------------</span>
<a name="line-306"></a>
<a name="line-307"></a><span class='hs-comment'>-- | Contains the number of menu items in the /current menu./</span>
<a name="line-308"></a>
<a name="line-309"></a><a name="numMenuItems"></a><span class='hs-definition'>numMenuItems</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>GettableStateVar</span> <span class='hs-conid'>Int</span>
<a name="line-310"></a><span class='hs-definition'>numMenuItems</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>makeGettableStateVar</span> <span class='hs-varop'>$</span> <span class='hs-varid'>simpleGet</span> <span class='hs-varid'>fromIntegral</span> <span class='hs-varid'>glut_MENU_NUM_ITEMS</span>
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