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| 970ed795 | 1 | <!-- |
| 3abe9331 | 2 | Copyright (c) 2000-2015 Ericsson Telecom AB |
| 970ed795 EL |
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| 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>function</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="from.html" alt="previous"><img border="0" src="../images/left.jpg" width="53" height="40"></a></td> | |
| 26 | <td><a href="get_stringencoding.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>function</h1> | |
| 33 | <blockquote> | |
| 34 | <p>1. <a href="#4.">Declaring a function</a></p> | |
| 35 | <p>2. <a href="#5."> Declaring an external function</a></p> | |
| 36 | </blockquote> | |
| 37 | <p>Functions are used to determine test behavior, organize test execution and structure computation. They can be defined within a module or externally; restricted to a component or not. They may | |
| 38 | have parameters and return a single value.</p> | |
| 39 | <p>Related keywords:</p> | |
| 40 | <ul> | |
| 41 | <li><a href="in.html"><b><font face="Courier New" color="#003258" size="4">in</font></b></a></li> | |
| 42 | <li><a href="inout.html"><b><font face="Courier New" color="#003258" size="4">inout</font></b></a></li> | |
| 43 | <li><a href="out.html"><b><font face="Courier New" color="#003258" size="4">out</font></b></a></li> | |
| 44 | <li><a href="return.html"><b><font face="Courier New" color="#003258" size="4">return</font></b></a></li> | |
| 45 | <li><a href="runs.html"><b><font face="Courier New" color="#003258" size="4">runs</font></b></a> <a href="on.html"><b><font face="Courier New" color="#003258" size="4">on</font></b></a></li> | |
| 46 | <li><a href="template.html"><b><font face="Courier New" color="#003258" size="4">template</font></b></a></li> | |
| 47 | </ul> | |
| 48 | <hr align="left" width="75%"> | |
| 49 | <h4><a name="4.">1. Declaring a function</a></h4> | |
| 50 | <hr align="left" width="50%"> | |
| 51 | <div align="center"> | |
| 52 | <center> | |
| 53 | <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4"> | |
| 54 | <tr> | |
| 55 | <td width="100%"> | |
| 56 | <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>function</b></font><i> function_identifier </i> <font face="Courier New" color="#003258" size="5"><b>(</b></font> [<i> | |
| 57 | value </i>|<i>timer </i>|<i>template </i>|<i>port </i> ... ] <font face="Courier New" color="#003258" size="5"><b>)</b></font>[ <font face="Courier New" color="#003258" size="5"><b>runs | |
| 58 | on</b></font><i> component_reference </i>] [ <font face="Courier New" color="#003258" size="5"><b>return</b></font><i> returned_type </i>] <font face="Courier New" color="#003258" size="5"><b>{</b></font><i>statement_block</i><font | |
| 59 | face="Courier New" color="#003258" size="5"><b>};</b></font></h3> | |
| 60 | </td> | |
| 61 | </tr> | |
| 62 | </table> | |
| 63 | </center> | |
| 64 | </div> | |
| 65 | <ul> | |
| 66 | <li> | |
| 67 | <p>The <font face="Courier New" color="#003258" size="4"><b>function</b></font> keyword introduces the function definition.</p> | |
| 68 | </li> | |
| 69 | <li> | |
| 70 | <p><i>function_identifier</i> is the name used to refer to the function. Must begin with a letter, may contain letters, numbers and underscore characters. According to the <a | |
| 71 | href="../docs/naming.pdf" target="_blank">Naming convention</a>, the prefix <b> f_</b> is recommended.</p> | |
| 72 | </li> | |
| 73 | <li> | |
| 74 | <p><a name="inout"><i>value</i> </a> indicates a value parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="in.html"><font | |
| 75 | face="Courier New" size="4"><b>in</b></font></a>, <a href="out.html"><font face="Courier New" size="4"><b>out</b></font></a> or <a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 76 | continues with a reference to a built-in type (cf. <a href="const.html#par1">their list</a>) or a <a href="type.html"> referenced type</a> and ends by a parameter | |
| 77 | identifier.</p> | |
| 78 | </li> | |
| 79 | <li> | |
| 80 | <p><i>timer</i> indicates a timer parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 81 | continues with the keyword <font face="Courier New"><b>timer</b></font> and ends by a parameter identifier.</p> | |
| 82 | </li> | |
| 83 | <li> | |
| 84 | <p><a name="template"><i>template</i> </a> indicates a template parameter. A template parameter may hold values defined for the value parameter and, in addition, the special value omit, | |
| 85 | matching symbols (?, * etc.) and templates. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 86 | continues with the keyword <font face="Courier New"><b>template</b></font>, a reference to a built-in type (cf. <a href="const.html#par1">their list</a>) or a <a href="type.html" | |
| 87 | target="_blank"> referenced type</a>and ends by a parameter identifier.</p> | |
| 88 | </li> | |
| 89 | <li> | |
| 90 | <p><i>port</i> indicates a port parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 91 | continues with the port type identifier and ends by a parameter identifier.</p> | |
| 92 | </li> | |
| 93 | <li> | |
| 94 | <p><b>...</b> indicates that all kind of parameters (<i>value</i>, <i>timer</i>, <i>template</i> and <i>port</i>) may be repeated. They are separated by comma.</p> | |
| 95 | </li> | |
| 96 | <li> | |
| 97 | <p><a name="The optional">The optional</a> keywords <font face="Courier New" color="#003258" size="4"><b>runs on</b></font> restrict the function to a component.</p> | |
| 98 | </li> | |
| 99 | <li> | |
| 100 | <p><i>component_reference</i> refers to the component the function is tied to. It is composed of two parts: the module identifier (may be omitted) and the component tpye identifier. The two | |
| 101 | parts are linked by a dot.</p> | |
| 102 | </li> | |
| 103 | <li> | |
| 104 | <p><a name="return">The</a> optional keyword <font face="Courier New" color="#003258" size="4"><b>return</b></font> indicates that the function returns a value</p> | |
| 105 | </li> | |
| 106 | <li> | |
| 107 | <p align="left"><i>returned_type</i> is one of the built-in types (cf. <a href="const.html#par1">their list</a>) or <a href="type.html"> referenced types</a> | |
| 108 | determining what kind of a value will be returned</p> | |
| 109 | </li> | |
| 110 | <li> | |
| 111 | <p align="left"><i><a name="statement_block">statement_block</a></i> may contain both local definitions (of constants, variables and timers) visible only in the defined function and the program | |
| 112 | part describing the program behavior.</p> | |
| 113 | </li> | |
| 114 | </ul> | |
| 115 | <p><a href="#Ex4">Example</a></p> | |
| 116 | <hr align="left" width="75%" color="#0094D2"> | |
| 117 | <h4><a name="5.">2. Declaring an external function</a></h4> | |
| 118 | <hr align="left" width="50%" color="#0094D2"> | |
| 119 | <div align="center"> | |
| 120 | <center> | |
| 121 | <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4"> | |
| 122 | <tr> | |
| 123 | <td width="100%"> | |
| 124 | <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>external function</b></font><i> function_identifier </i> <font face="Courier New" color="#003258" size="5"><b>(</b></font> | |
| 125 | [<i> value </i>|<i>timer </i>|<i>template </i>|<i>port </i> ... ] <font face="Courier New" color="#003258" size="5"><b>)</b></font> [ <font face="Courier New" color="#003258" size="5"><b>return</b></font><i> | |
| 126 | returned_type </i>] <font face="Courier New" color="#003258" size="5"><b>;</b></font></h3> | |
| 127 | </td> | |
| 128 | </tr> | |
| 129 | </table> | |
| 130 | </center> | |
| 131 | </div> | |
| 132 | <ul> | |
| 133 | <li> | |
| 134 | <p>The <font face="Courier New" color="#003258" size="4"><b>external function</b></font> keywords mean that the function is defined in a module other than TTCN-3 or ASN.1 (for example in a | |
| 135 | module written in C++).</p> | |
| 136 | </li> | |
| 137 | <li> | |
| 138 | <p><i>function_identifier</i> is the name used to refer to the function. Must begin with a letter, may contain letters, numbers and underscore characters.</p> | |
| 139 | </li> | |
| 140 | <li> | |
| 141 | <p><i>value</i> indicates a value parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="in.html"><font face="Courier New" size="4"><b>in</b></font></a>, | |
| 142 | <a href="out.html"><font face="Courier New" size="4"><b>out</b></font></a> or <a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), continues with a reference to a | |
| 143 | built-in type (cf. <a href="const.html#par1">their list</a>) or a <a href="type.html">referenced type</a> and ends by a parameter identifier.</p> | |
| 144 | </li> | |
| 145 | <li> | |
| 146 | <p><i>timer</i> indicates a timer parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 147 | continues with the keyword <font face="Courier New"><b>timer</b></font> and ends by a parameter identifier.</p> | |
| 148 | </li> | |
| 149 | <li> | |
| 150 | <p><i>template</i> indicates a template parameter. A template parameter may hold values defined for the value parameter and, in addition, the special value omit, matching symbols (?, * | |
| 151 | etc.) and templates. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 152 | continues with the keyword <font face="Courier New"><b>template</b></font>, a reference to a built-in type (cf. <a href="const.html#par1">their list</a>) or a <a href="type.html" | |
| 153 | target="_blank"> referenced type</a>and ends by a parameter identifier.</p> | |
| 154 | </li> | |
| 155 | <li> | |
| 156 | <p><i>port</i> indicates a port parameter. The expression begins with an optional keyword indicating the parameter passing method (<a href="inout.html"><font face="Courier New" size="4"><b>inout</b></font></a>), | |
| 157 | continues with the port type identifier and ends by a parameter identifier.</p> | |
| 158 | </li> | |
| 159 | <li> | |
| 160 | <p><b>...</b> indicates that all kind of parameters (<i>value</i>, <i>timer</i>, <i>template</i> and <i>port</i>) may be repeated. They are separated by comma.</p> | |
| 161 | </li> | |
| 162 | <li> | |
| 163 | <p>The optional keyword <font face="Courier New" color="#003258" size="4"><b>return</b></font> indicates that the function returns a value</p> | |
| 164 | </li> | |
| 165 | <li> | |
| 166 | <p align="left"><i>returned_type</i> is one of the built-in types (cf. <a href="const.html#par1">their list</a>) or <a href="type.html"> referenced types</a> | |
| 167 | determining what kind of a value will be returned</p> | |
| 168 | </li> | |
| 169 | </ul> | |
| 170 | <p><a href="#Ex5">Example</a></p> | |
| 171 | <hr align="left" width="50%"> | |
| 172 | <hr align="left" width="50%"> | |
| 173 | <p><a name="Ex4">Example 1a</a>: | |
| 174 | <p><font face="Courier New">function f_MyF_1 (integer pl_1, boolean pl_2) {};</font></p> | |
| 175 | <p>The function f_MyF_1 has two input parameters (the integer pl_1 and the Boolean pl_2). No value is returned and the function is not restricted to a given component. The statement block is | |
| 176 | empty.</p> | |
| 177 | <p>Example 1b: | |
| 178 | <p><font face="Courier New">function f_MyF_2() return integer { return 28 };</font></p> | |
| 179 | <p>The function f_MyF_2 has no input parameters but an integer value is returned. The function is not restricted to a given component. The statement block is always returns the integer value 28.</p> | |
| 180 | <p>Example 1c: | |
| 181 | <p><font face="Courier New">function f_MyF_3() runs on MyCompType_CT {};</font></p> | |
| 182 | <p>The function f_MyF_3 has neither input parameters nor returns any value. The function is not restricted to the component MyCompType_CT. The statement block is empty.</p> | |
| 183 | <p><a name="Ex5">Example 2</a>: | |
| 184 | <p><font face="Courier New">external function f_Utifraan() return float;</font></p> | |
| 185 | <p>The function called f_Utifraan MonConst is defined in an external module, e.g. in a module written in C++. It has no input parameters but returns a floating point value.</p> | |
| 186 | <hr align="left" width="25%"> | |
| 187 | <hr align="left" width="25%"> | |
| 188 | <p><a HREF="BNF.html#functiondef">BNF definition</a> of <font face="Courier New"> function</font></p> | |
| 189 | </body> | |
| 190 | </html> |