help/info/friend.html

   1 <!--
   2  Copyright (c) 2000-2016 Ericsson Telecom AB
   3  All rights reserved. This program and the accompanying materials
   4  are made available under the terms of the Eclipse Public License v1.0
   5  which accompanies this distribution, and is available at
   6  http://www.eclipse.org/legal/epl-v10.html
   7
   8  Contributors:
   9   Baji, Laszlo
  10   Balasko, Jeno
  11   Szabados, Kristof
  12 -->
  13 <html>
  14 <head>
  15 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  16 <meta http-equiv="Content-Language" content="en-us">
  17 <title>friend</title>
  18 </head>
  19 <body bgcolor="#DAD3C5" vlink="#0094D2" link="#003258">
  20 <table align="left" border="0" cellspacing="0" cellpadding="0" valign=top>
  21   <tr>
  22     <td width=105 height=40><a href="https://projects.eclipse.org/projects/tools.titan"><img src="../images/titan_transparent.gif" border=0 width=105 height=40 align="left" alt="Titan"></a></td>
  23   </tr>
  24 </table>
  25 <table border="0" align="right" cellpadding="0" cellspacing="0">
  26   <tr>
  27     <td><a href="../titan_main.html" alt="contents"><img border="0" src="../images/ao.jpg" width="53" height="40"></a></td>
  28     <td><a href="../titan_index.html" alt="index"><img border="0" src="../images/up.jpg" width="53" height="40"></a></td>
  29     <td><a href="for.html" alt="previous"><img border="0" src="../images/left.jpg" width="53" height="40"></a></td>
  30     <td><a href="from.html" alt="next"><img border="0" src="../images/right.jpg" width="53" height="40"></a></td>
  31   </tr>
  32 </table>
  33 <p><br clear="all">
  34 </p>
  35 <hr>
  36 <h1>friend</h1>
  37 <blockquote>
  38 <p>1. <a href="#1."> Declaring a definition with friend visibility</a></p>
  39 <p>2. <a href="#2."> Declaring a friend module</a></p>
  40 </blockquote>
  41 <hr align="left" width="75%">
  42 <h4><a name="1.">1. Declaring a definition with friend visibility</a></h4>
  43 <hr align="left" width="50%">
  44 <p>Friend is a visibility modifier, that can be atteched to definitions on module level. Where it means that the definition is visible in every friend module where it is imported to.
  45 <div align="center">
  46 <center>
  47 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  48   <tr>
  49     <td width="100%">
  50     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>friend definition;</b></font></h3>
  51     </td>
  52   </tr>
  53 </table>
  54 </center>
  55 </div>
  56 <p><a href="#Ex1">Example</a></p>
  57 <hr align="left" width="75%">
  58 <h4><a name="1.">2. Declaring a friend module</a></h4>
  59 <hr align="left" width="50%">
  60 <p>A module can declare his friend modules, for which its friend definition will be visible.
  61 <div align="center">
  62 <center>
  63 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  64   <tr>
  65     <td width="100%">
  66     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>friend module identifier_list;</b></font></h3>
  67     </td>
  68   </tr>
  69 </table>
  70 </center>
  71 </div>
  72 <p><a href="#Ex1">Example</a></p>
  73 <hr align="left" width="75%">
  74 <p>Related keywords:</p>
  75 <ul>
  76   <li><a href="public.html"><b><font face="Courier New" color="#003258" size="4">public</font></b></a></li>
  77   <li><a href="private.html"><b><font face="Courier New" color="#003258" size="4">private</font></b></a></li>
  78 </ul>
  79 <p><a name="Ex1">Example 1</a>:
  80 <p><font face="Courier New">module module1 {<br>
  81 import from module2 all;<br>
  82 <br>
  83 const module2Type c_example1 := 4; //by default public, visible<br>
  84 const module2PublieType c_example2 := 4; //public, visible<br>
  85 const module2FriendType c_example3 := 4; //this is a friend module, visible<br>
  86 const module2PrivateType c_example4 := 4; //ERROR, not visible<br>
  87 }</font>
  88 <p><font face="Courier New">module module2 {<br>
  89 friend module1;<br>
  90 <br>
  91 type integer module2Type;//by default public, visible in every module<br>
  92 public type integer module2PublieType; //public, visible in every module<br>
  93 friend type integer module2FriendType; //friend, visible only in friend modules<br>
  94 private type module2PrivateType; //private, visible only in this module<br>
  95 }</font>
  96 <hr align="left" width="25%">
  97 <hr align="left" width="25%">
  98 </body>
  99 </html>