<html>
<head>
<title>Gri: `while' command</title>
</head>
<body bgcolor="#FFFFFF" text="#000000" link="#0000EE" vlink="#551A8B" alink="FF0000">
<!-- newfile While.html "Gri: `while' command" "Gri Commands" -->
<!-- @node While, Write, Unlink, List Of Gri Commands -->
<a name="While" ></a>
<img src="./resources/top_banner.gif" usemap="#navigate_top" border="0">
<table summary="top banner" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="150" valign="top">
<font size=-1>
<br>
Chapters:
</br>
<a href="Introduction.html">1: Introduction</a><br>
<a href="SimpleExample.html">2: Simple example</a><br>
<a href="InvokingGri.html">3: Invocation</a><br>
<a href="GettingMoreControl.html">4: Finer Control</a><br>
<a href="X-Y.html">5: X-Y Plots</a><br>
<a href="ContourPlots.html">6: Contour Plots</a><br>
<a href="Images.html">7: Image Plots</a><br>
<a href="Examples.html">8: Examples</a><br>
<a href="Commands.html">9: Gri Commands</a><br>
<a href="Programming.html">10: Programming</a><br>
<a href="Environment.html">11: Environment</a><br>
<a href="Emacs.html">12: Emacs Mode</a><br>
<a href="History.html">13: History</a><br>
<a href="Installation.html">14: Installation</a><br>
<a href="Bugs.html">15: Gri Bugs</a><br>
<a href="TestSuite.html">16: Test Suite</a><br>
<a href="Acknowledgments.html">17: Acknowledgments</a><br>
<a href="License.html">18: License</a><br>
<br>
Indices:</br>
<a href="ConceptIndex.html"><i>Concepts</i></a><br>
<a href="CommandIndex.html"><i>Commands</i></a><br>
<a href="BuiltinIndex.html"><i>Variables</i></a><br>
</font>
<td width="500" valign="top">
<map name="navigate_top">
<area alt="index.html#Top" shape="rect" coords="5,2,218,24" href="index.html#Top">
<area alt="ListOfGriCommands.html#ListOfGriCommands" shape="rect" coords="516,2,532,24" href="ListOfGriCommands.html#ListOfGriCommands">
<area alt="Gri: `unlink' command" shape="rect" coords="557,2,573,24" href="Unlink.html">
<area alt="Gri: Write commands" shape="rect" coords="581,2,599,24" href="Write.html">
</map>
<map name="navigate_bottom">
<area alt="index.html#Top" shape="rect" coords="5,2,218,24" href="index.html#Top">
<area alt="Gri: Write commands" shape="rect" coords="581,2,599,24" href="Write.html"></map>
<h3>9.3.51: `<font color="#82140F"><code>while</code></font>'</h3>
<!-- latex: \index{while} -->
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<font color="#82140F">
`while .test.|{rpn ...}'
</font></PRE>
</TD>
</TR>
</TABLE>
<p>
Perform statements in loop while the value of `<font color="#82140F"><code>.test.</code></font>' or the RPN
expression is nonzero. The end of the loop designated by a line
containing the words `<font color="#82140F"><code>end while</code></font>'. The value `<font color="#82140F"><code>.test.</code></font>' may be
an rpn expression. To leave the loop prematurely, use a `<font color="#82140F"><code>break</code></font>'
statement. Upon encountering a `<font color="#82140F"><code>break</code></font>' statement, Gri jumps to the
line immediately following the loop. If the `<font color="#82140F"><code>-chatty</code></font>' option is
nonzero, a notification is printed every 1000 passes through the loop,
as a debugging measure to catch unintended infinite loops.
<p>
<b>Examples</b>:
<p>
<ul>
<li>
Loop forever, printing a message over and over.
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<font color="#82140F">
while 1
show "This loops forever. Need to 'break'"
end while
</font></PRE>
</TD>
</TR>
</TABLE>
<p>
<li>
Repeatedly read two numbers, and plot a bullet at the indicated
location. If (or, hopefully, ``when'') the end of the file is
encountered, break out of the loop; otherwise continue plotting forever.
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<font color="#82140F">
while 1
read .x. .y.
if ..eof..
break
end if
draw symbol bullet at .x. .y.
end while
<p>
</font></PRE>
</TD>
</TR>
</TABLE>
<li>
Loop 10 times, printing the values of `<font color="#82140F"><code>.i.</code></font>' as they range 0, 1,
..., 9. After exiting from the loop, `<font color="#82140F"><code>.i.</code></font>' will equal 10. Be
<b>careful</b> to use the correct rpn greater-than test to avoid an
infinite loop.
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<font color="#82140F">
.i. = 0
while {rpn .i. 10 >}
show .i.
.i. += 1
end while
</font></PRE>
</TD>
</TR>
</TABLE>
<p>
</ul>
<p>
</table>
<img src="./resources/bottom_banner.gif" usemap="#navigate_bottom" border="0">
</body>
</html>
distrib
>
Mandriva
>
8.2
>
i586
>
media
>
contrib
>
by-pkgid
>
8b2b1fb157760a0d31e072e140388824
>
files
>
181
