help/info/friend.html

   1 <!--
   2  Copyright (c) 2000-2015 Ericsson Telecom AB
   3
   4  All rights reserved. This program and the accompanying materials
   5  are made available under the terms of the Eclipse Public License v1.0
   6  which accompanies this distribution, and is available at
   7  http://www.eclipse.org/legal/epl-v10.html
   8  -->
   9 <html>
  10 <head>
  11 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  12 <meta http-equiv="Content-Language" content="en-us">
  13 <title>friend</title>
  14 </head>
  15 <body bgcolor="#DAD3C5" vlink="#0094D2" link="#003258">
  16 <table align="left" border="0" cellspacing="0" cellpadding="0" valign=top>
  17   <tr>
  18     <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>
  19   </tr>
  20 </table>
  21 <table border="0" align="right" cellpadding="0" cellspacing="0">
  22   <tr>
  23     <td><a href="../titan_main.html" alt="contents"><img border="0" src="../images/ao.jpg" width="53" height="40"></a></td>
  24     <td><a href="../titan_index.html" alt="index"><img border="0" src="../images/up.jpg" width="53" height="40"></a></td>
  25     <td><a href="for.html" alt="previous"><img border="0" src="../images/left.jpg" width="53" height="40"></a></td>
  26     <td><a href="from.html" alt="next"><img border="0" src="../images/right.jpg" width="53" height="40"></a></td>
  27   </tr>
  28 </table>
  29 <p><br clear="all">
  30 </p>
  31 <hr>
  32 <h1>friend</h1>
  33 <blockquote>
  34 <p>1. <a href="#1."> Declaring a definition with friend visibility</a></p>
  35 <p>2. <a href="#2."> Declaring a friend module</a></p>
  36 </blockquote>
  37 <hr align="left" width="75%">
  38 <h4><a name="1.">1. Declaring a definition with friend visibility</a></h4>
  39 <hr align="left" width="50%">
  40 <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.
  41 <div align="center">
  42 <center>
  43 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  44   <tr>
  45     <td width="100%">
  46     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>friend definition;</b></font></h3>
  47     </td>
  48   </tr>
  49 </table>
  50 </center>
  51 </div>
  52 <p><a href="#Ex1">Example</a></p>
  53 <hr align="left" width="75%">
  54 <h4><a name="1.">2. Declaring a friend module</a></h4>
  55 <hr align="left" width="50%">
  56 <p>A module can declare his friend modules, for which its friend definition will be visible.
  57 <div align="center">
  58 <center>
  59 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  60   <tr>
  61     <td width="100%">
  62     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>friend module identifier_list;</b></font></h3>
  63     </td>
  64   </tr>
  65 </table>
  66 </center>
  67 </div>
  68 <p><a href="#Ex1">Example</a></p>
  69 <hr align="left" width="75%">
  70 <p>Related keywords:</p>
  71 <ul>
  72   <li><a href="public.html"><b><font face="Courier New" color="#003258" size="4">public</font></b></a></li>
  73   <li><a href="private.html"><b><font face="Courier New" color="#003258" size="4">private</font></b></a></li>
  74 </ul>
  75 <p><a name="Ex1">Example 1</a>:
  76 <p><font face="Courier New">module module1 {<br>
  77 import from module2 all;<br>
  78 <br>
  79 const module2Type c_example1 := 4; //by default public, visible<br>
  80 const module2PublieType c_example2 := 4; //public, visible<br>
  81 const module2FriendType c_example3 := 4; //this is a friend module, visible<br>
  82 const module2PrivateType c_example4 := 4; //ERROR, not visible<br>
  83 }</font>
  84 <p><font face="Courier New">module module2 {<br>
  85 friend module1;<br>
  86 <br>
  87 type integer module2Type;//by default public, visible in every module<br>
  88 public type integer module2PublieType; //public, visible in every module<br>
  89 friend type integer module2FriendType; //friend, visible only in friend modules<br>
  90 private type module2PrivateType; //private, visible only in this module<br>
  91 }</font>
  92 <hr align="left" width="25%">
  93 <hr align="left" width="25%">
  94 </body>
  95 </html>