Artifact bd095fbd3946ecff96c97eee95a5b728527b0d3dfa05ebfa0e669972b05cef4e:

• Executable file r37/lisp/csl/html/r37_0039.html — part of check-in [f2fda60abd] at 2011-09-02 18:13:33 on branch master — Some historical releases purely for archival purposes

  git-svn-id: https://svn.code.sf.net/p/reduce-algebra/code/trunk/historical@1375 2bfe0521-f11c-4a00-b80e-6202646ff360 (user: arthurcnorman@users.sourceforge.net, size: 1224) [annotate] [blame] [check-ins using] [more...]

<A NAME=AND>

<TITLE>AND</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>AND</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
<P>
 
The <em>and</em> binary logical operator returns true if both of its 
arguments are true. 
<P>
<P>
 <P> <H3> 
syntax: </H3>
&lt;logical\_expression&gt; <em>and</em> &lt;logical\_expression&gt; 
<P>
<P>
<P>
&lt;logical\_expression&gt; must evaluate to true or nil. 
<P>
<P>
 <P> <H3> 
examples: </H3>
<P><PRE><TT>
a := 12; 

  A := 12 


if numberp a and a &lt; 15 then write a**2 else write &quot;no&quot;;
 


  144 


clear a; 

if numberp a and a &lt; 15 then write a**2 else write &quot;no&quot;;
 


  no

</TT></PRE><P>Logical operators can only be used inside conditional statements, 
such as 

<A HREF=r37_0228.html>while</A>...<em>do</em> or 

<A HREF=r37_0052.html>if</A>...<em>then</em>...<em>else</em>. <em>and</em> exami
nes each of 
its arguments in order, and quits, returning nil, on finding an 
argument that is not true. An error results if it is used in other 
contexts. 
<P>
<P>
<em>and</em>is left associative: <em>x and y and z</em> is equivalent to 
<em>(x and y) and z</em>. 
<P>
<P>
<P>