<html>
<head>
<title>Gri: creating a complicated new command</title>
</head>
<body bgcolor="#FFFFFF" text="#000000" link="#0000EE" vlink="#551A8B" alink="FF0000">
<!-- newfile ComplicatedNewCommand.html "Gri: creating a complicated new command" "Programming Gri" -->
<!-- @node Complicated New Command, Changeable Command Arguments, Simple New Command, Adding New Commands -->
<a name="ComplicatedNewCommand" ></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="NewCommands.html#AddingNewCommands" shape="rect" coords="516,2,532,24" href="NewCommands.html#AddingNewCommands">
<area alt="Gri: creating a simple new command" shape="rect" coords="557,2,573,24" href="SimpleNewCommand.html">
<area alt="Gri: making a newcommand change its arguments" shape="rect" coords="581,2,599,24" href="ChangeableCommandArguments.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: making a newcommand change its arguments" shape="rect" coords="581,2,599,24" href="ChangeableCommandArguments.html"></map>
<h3>10.11.4: Complicated example of a new command</h3>
The following example from the global `<font color="#82140F"><samp>gri.cmd</samp></font>' file illustrates
how to parse/check the commandline (see <a href="Synonyms.html#LocalSynonyms">Local Synonyms</a>), which is a
good practice in any code you expect to re-use. The first `<font color="#82140F"><code>if</code></font>'
statement checks that the word `<font color="#82140F"><code>at</code></font>' is in the right place (this
would not have been checked by the syntax matcher, the word having
followed a string). The presence of the keyword `<font color="#82140F"><code>cm</code></font>' is checked
for, and user units or cm units are used accordingly. Local variables
are created (`<font color="#82140F"><code>new</code></font>') and then destroyed (`<font color="#82140F"><code>delete</code></font>') so that
this new command cannot affect outside code.
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%">
<TR>
<TD>
<PRE>
<font color="#82140F">
`draw label whiteunder "\string" at .ll_x. .ll_y. [cm]'
Draw label for plot, located with lower-left corner
at indicated (x,y) position (specified in user
units or in cm on the page). Whiteout is used
to clean up the area under the label. BUGS:
Cannot handle angled text; doesn't check for
super/subscripts.
{
if {rpn "\.word4." "at" !=}
show "ERROR: 5th word must be `at', not `\.word4.'"
show traceback
quit
end if
new .x. .y. .oldgray. .space.
if {rpn \.words. 7 ==}
.x. = {rpn \.word5. xusertocm}
.y. = {rpn \.word6. yusertocm}
else if {rpn \.words. 8 ==}
if {rpn "\.word7." "cm" !=}
show "ERROR: Require 8th word to be `cm'"
show traceback
quit
end if
.x. = \.word5.
.y. = \.word6.
else
show "ERROR: Require 7 or 8 words, not \.words."
show traceback
quit
end if
# Coordinates now in cm. Next, white out a box
# under the text (and .space. centimetres
# beyond text), then draw label.
.space. = 0.1 # Space of 1mm
.oldgray. = ..graylevel..
set graylevel white
draw box filled \
{rpn .x. .space. -} \
{rpn .y. .space. -} \
{rpn .x. "\.word3." width + .space. +} \
{rpn .y. "M" ascent + .space. + } cm
set graylevel .oldgray.
draw label "\.word3." at .x. .y. cm
delete .x. .y. .oldgray. .space.
}
</font></PRE>
</TD>
</TR>
</TABLE>
<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
>
33
