help/info/break.html

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  18 <title>break</title>
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  34 <p><br clear="all">
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  36 <hr>
  37 <h1>break</h1>
  38 <hr align="left" width="75%">
  39 <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
  40   face="Courier New"><b>altstep</b></font> definitions.</p>
  41 <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>,
  42 <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
  43 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>
  44 <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>
  45 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>
  46 or <font face="Courier New"><b>call</b></font> statement is left. Execution continues with the statement following the construct which is left.</p>
  47 <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>
  48 or <font face="Courier New"><b>call</b></font> statement):<br>
  49 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
  50 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
  51   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
  52 block is skipped (and the <font face="Courier New"><b>alt</b></font> statement is left).</p>
  53 <hr align="left" width="50%">
  54 <p>Related keyword:</p>
  55 <ul>
  56   <li><a href="for.html"><b><font face="Courier New" color="#003258" size="4">for</font></b></a></li>
  57   <li><a href="while.html"><b><font face="Courier New" color="#003258" size="4">while</font></b></a></li>
  58   <li><a href="do.html"><b><font face="Courier New" color="#003258" size="4">do-while</font></b></a></li>
  59   <li><a href="alt.html"><b><font face="Courier New" color="#003258" size="4">alt</font></b></a></li>
  60   <li><a href="interleave.html"><b><font face="Courier New" color="#003258" size="4">interleave</font></b></a></li>
  61   <li><a href="call.html"><b><font face="Courier New" color="#003258" size="4">call</font></b></a></li>
  62   <li><a href="altstep.html"><b><font face="Courier New" color="#003258" size="4">altstep</font></b></a></li>
  63 </ul>
  64 <hr align="left" width="50%">
  65 <div align="center">
  66 <center>
  67 <table border="0" width="90%" bgcolor="#FFB599" cellpadding="4">
  68   <tr>
  69     <td width="100%">
  70     <h3 align="center"><font face="Courier New" color="#003258" size="5"><b>break;</b></font></h3>
  71     </td>
  72   </tr>
  73 </table>
  74 </center>
  75 </div>
  76 <hr align="left" width="25%">
  77 <P>Example 1:
  78 <p><code> do {<br>
  79 &nbsp;&nbsp;/* ... */<br>
  80 &nbsp;&nbsp;if (cond1) { break; /* the do-while loop is left */ }<br>
  81 &nbsp;&nbsp;/* ... */<br>
  82 &nbsp;&nbsp;for (var integer j:=1; j<=10; j:= j+1) {<br>
  83 &nbsp;&nbsp;&nbsp;&nbsp;/* ... */<br>
  84 &nbsp;&nbsp;&nbsp;&nbsp;if (cond2) { break; /* the for-loop is left but the do-while loop is continued */ }<br>
  85 &nbsp;&nbsp;&nbsp;&nbsp;/* ... */<br>
  86 &nbsp;&nbsp;}<br>
  87 &nbsp;&nbsp;/* ... */<br>
  88 }<br></p>
  89 </code>
  90 <hr align="left" width="25%">
  91 <P>Example 2:
  92 <p><code> interleave {<br>
  93 &nbsp;&nbsp;[] PCO1.receive(integer:?) { /* do something here */ }<br>
  94 &nbsp;&nbsp;[] PCO2.receive(integer:?) { /* do something here, too */ }<br>
  95 &nbsp;&nbsp;[] T.timeout { break; }<br>
  96 }<br>
  97 </code></p>
  98 <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>
  99 <hr align="left" width="25%">
 100 <p><a HREF="BNF.html#breakstatement">BNF definition</a> of <font face="Courier New">break</font></p>
 101 </body>
 102 </html>