help/info/break.html

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  13 <title>break</title>
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  29 <p><br clear="all">
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  31 <hr>
  32 <h1>break</h1>
  33 <hr align="left" width="75%">
  34 <p>The keyword is used in loops and <font face="Courier New"><b>alt</b></font>, <font face="Courier New"><b>interleave</b></font> or <font face="Courier New"><b>call</b></font> statements and <font
  35   face="Courier New"><b>altstep</b></font> definitions.</p>
  36 <p>The <font face="Courier New"><b>break</b></font> statement may only be used inside the body of a loop (<font face="Courier New"><b>for</b></font>, <font face="Courier New"><b>while</b></font>,
  37 <font face="Courier New"><b>do-while</b></font>) or an alternative of an <font face="Courier New"><b>alt</b></font> or <font face="Courier New"><b>interleave</b></font> statement or response and
  38 exception handling parts of a <font face="Courier New"><b>call</b></font> statement or the statement block of an alternative of an <font face="Courier New"><b>altstep</b></font> definition.</p>
  39 <p>When used in loops or <font face="Courier New"><b>alt</b></font>, <font face="Courier New"><b>interleave</b></font> or <font face="Courier New"><b>call</b></font> statements:<br>
  40 On executing a <font face="Courier New"><b>break</b></font> statement the innermost, currently executed loop, <font face="Courier New"><b>alt</b></font>, <font face="Courier New"><b>interleave</b></font>
  41 or <font face="Courier New"><b>call</b></font> statement is left. Execution continues with the statement following the construct which is left.</p>
  42 <p>When used in <font face="Courier New"><b>altstep</b></font> definitions (but not inside a loop or an <font face="Courier New"><b>alt</b></font>, <font face="Courier New"><b>interleave</b></font>
  43 or <font face="Courier New"><b>call</b></font> statement):<br>
  44 On executing a <font face="Courier New"><b>break</b></font> statement the <font face="Courier New"><b>altstep</b></font> is left. If the <font face="Courier New"><b>altstep</b></font> was explicitly
  45 called as an alternative of an <font face="Courier New"><b>alt</b></font> statement or it was called as default for an <font face="Courier New"><b>alt</b></font> statement, then the <font
  46   face="Courier New"><b>alt</b></font> statement is also left. If the <font face="Courier New"><b>altstep</b></font> was explicitly called as an alternative with a statement block, then the statement
  47 block is skipped (and the <font face="Courier New"><b>alt</b></font> statement is left).</p>
  48 <hr align="left" width="50%">
  49 <p>Related keyword:</p>
  50 <ul>
  51   <li><a href="for.html"><b><font face="Courier New" color="#003258" size="4">for</font></b></a></li>
  52   <li><a href="while.html"><b><font face="Courier New" color="#003258" size="4">while</font></b></a></li>
  53   <li><a href="do.html"><b><font face="Courier New" color="#003258" size="4">do-while</font></b></a></li>
  54   <li><a href="alt.html"><b><font face="Courier New" color="#003258" size="4">alt</font></b></a></li>
  55   <li><a href="interleave.html"><b><font face="Courier New" color="#003258" size="4">interleave</font></b></a></li>
  56   <li><a href="call.html"><b><font face="Courier New" color="#003258" size="4">call</font></b></a></li>
  57   <li><a href="altstep.html"><b><font face="Courier New" color="#003258" size="4">altstep</font></b></a></li>
  58 </ul>
  59 <hr align="left" width="50%">
  60 <div align="center">
  61 <center>
  62 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  63   <tr>
  64     <td width="100%">
  65     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>break;</b></font></h3>
  66     </td>
  67   </tr>
  68 </table>
  69 </center>
  70 </div>
  71 <hr align="left" width="25%">
  72 <P>Example 1:
  73 <p><code> do {<br>
  74 &nbsp;&nbsp;/* ... */<br>
  75 &nbsp;&nbsp;if (cond1) { break; /* the do-while loop is left */ }<br>
  76 &nbsp;&nbsp;/* ... */<br>
  77 &nbsp;&nbsp;for (var integer j:=1; j<=10; j:= j+1) {<br>
  78 &nbsp;&nbsp;&nbsp;&nbsp;/* ... */<br>
  79 &nbsp;&nbsp;&nbsp;&nbsp;if (cond2) { break; /* the for-loop is left but the do-while loop is continued */ }<br>
  80 &nbsp;&nbsp;&nbsp;&nbsp;/* ... */<br>
  81 &nbsp;&nbsp;}<br>
  82 &nbsp;&nbsp;/* ... */<br>
  83 }<br></p>
  84 </code>
  85 <hr align="left" width="25%">
  86 <P>Example 2:
  87 <p><code> interleave {<br>
  88 &nbsp;&nbsp;[] PCO1.receive(integer:?) { /* do something here */ }<br>
  89 &nbsp;&nbsp;[] PCO2.receive(integer:?) { /* do something here, too */ }<br>
  90 &nbsp;&nbsp;[] T.timeout { break; }<br>
  91 }<br>
  92 </code></p>
  93 <p>With the usage of the <font face="Courier New"><b>break</b></font> statement a time limit for the execution of the <font face="Courier New"><b>interleave</b></font> statement is implemented.</p>
  94 <hr align="left" width="25%">
  95 <p><a HREF="BNF.html#breakstatement">BNF definition</a> of <font face="Courier New">break</font></p>
  96 </body>
  97 </html>