scilab/modules/string/help/en_US/evstr.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <!--
   3  * Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
   4  *
   5  * Copyright (C) 2012 - 2016 - Scilab Enterprises
   6  *
   7  * This file is hereby licensed under the terms of the GNU GPL v2.0,
   8  * pursuant to article 5.3.4 of the CeCILL v.2.1.
   9  * This file was originally licensed under the terms of the CeCILL v2.1,
  10  * and continues to be available under such terms.
  11  * For more information, see the COPYING file which you should have received
  12  * along with this program.
  13  *
  14  -->
  15 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink"
  16         xmlns:svg="http://www.w3.org/2000/svg" xmlns:ns5="http://www.w3.org/1999/xhtml"
  17         xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook"
  18         xmlns:scilab="http://www.scilab.org" xml:id="evstr" xml:lang="en">
  19     <refnamediv>
  20         <refname>evstr</refname>
  21         <refpurpose>evaluation of expressions</refpurpose>
  22     </refnamediv>
  23     <refsynopsisdiv>
  24         <title>Syntax</title>
  25         <synopsis>
  26             H = evstr(Z)
  27             [H, ierr] = evstr(Z)
  28         </synopsis>
  29     </refsynopsisdiv>
  30     <refsection>
  31         <title>Arguments</title>
  32         <variablelist>
  33             <varlistentry>
  34                 <term>Z</term>
  35                 <listitem>
  36                     <para>
  37                         a matrix of character strings <varname>M</varname> or
  38                         <code>list(M,Subexp)</code>
  39                     </para>
  40                     <variablelist>
  41                         <varlistentry>
  42                             <term>M</term>
  43                             <listitem>
  44                                 <para>a matrix of character strings.</para>
  45                             </listitem>
  46                         </varlistentry>
  47                         <varlistentry>
  48                             <term>Subexp</term>
  49                             <listitem>
  50                                 <para>a vector of character strings.</para>
  51                             </listitem>
  52                         </varlistentry>
  53                     </variablelist>
  54                 </listitem>
  55             </varlistentry>
  56             <varlistentry>
  57                 <term>H</term>
  58                 <listitem>
  59                     <para>a matrix.</para>
  60                 </listitem>
  61             </varlistentry>
  62             <varlistentry>
  63                 <term>ierr</term>
  64                 <listitem>
  65                     <para>an integer, error indicator.</para>
  66                 </listitem>
  67             </varlistentry>
  68         </variablelist>
  69     </refsection>
  70     <refsection>
  71         <title>Description</title>
  72         <para>
  73             Returns the result of the evaluation of the matrix of character
  74             strings <varname>M</varname>. Each element of the matrix must define a
  75             valid Scilab expression.
  76         </para>
  77         <para>
  78             If the evaluation of <varname>M</varname> expression leads to an
  79             error, the single return value version, <code>H = evstr(M)</code>,
  80             raises the error as usual. The two return values version,
  81             <code>[H,ierr] = evstr(M)</code>, on the other hand, produces no
  82             error, but returns the error number in <varname>ierr</varname>.
  83         </para>
  84         <para>
  85             If <varname>Z</varname> is a list, <varname>Subexp</varname> is a
  86             vector of character strings, that defines subexpressions which are
  87             evaluated before evaluating <varname>M</varname>. These subexpressions
  88             must be referred to as <literal>%(k)</literal> in <varname>M</varname>,
  89             where <literal>k</literal> is the subexpression's index in
  90             <varname>Subexp</varname>.
  91         </para>
  92         <para>
  93             <code>evstr('a = 1')</code> is not valid (use <function>execstr</function>
  94             instead).
  95         </para>
  96         <para>
  97             <literal>Nan</literal>, <literal>NaN</literal> will be interpreted as <constant>%nan</constant>.
  98         </para>
  99         <para>
 100             <literal>Inf</literal> will be interpreted as <constant>%inf</constant>.
 101         </para>
 102         <warning>
 103             <varname>Z</varname> should not include any continuation marks (..).
 104         </warning>
 105     </refsection>
 106     <refsection>
 107         <title>Examples</title>
 108         <programlisting role="example"><![CDATA[
 109 a = 1; b = 2;
 110 Z = ['a', 'b'] ;
 111 evstr(Z)
 112
 113 Z = list(['%(1)','%(1)-%(2)'],['a+1','b+1']);
 114 evstr(Z)
 115
 116 evstr('NaN'), evstr('Inf')
 117
 118 //The two return values version
 119 [H, ierr] = evstr(Z) // no error
 120 Z = ['a', 'b', 'c'] ;// the variable c is undefined
 121 [H, ierr] = evstr(Z) // error 4: Undefined variable: c
 122 ]]>    </programlisting>
 123     </refsection>
 124     <refsection role="see also">
 125         <title>See also</title>
 126         <simplelist type="inline">
 127             <member>
 128                 <link linkend="execstr">execstr</link>
 129             </member>
 130         </simplelist>
 131     </refsection>
 132 </refentry>