View source for $ChkPat

<p>
The <var>$ChkPat</var> function verifies the syntax of a pattern. If the pattern is valid, a null string is returned; otherwise, an error message string is returned.</p>

==Syntax==
<p class="syntax">$ChkPat(<span class="term">pattern</span>[,<span class="term">language</span>])
</p>
<p>
Where:</p>
<ul>
<li>The required <var class="term">pattern</var> argument is the string of characters to verify, which can be a literal enclosed in quotation marks or a %variable.
<!-- This is not really required and probably we should change the doc to say that it defaults to the null string, which is a valid pattern. That example is used in QASHR tests SOUL.DME.263.QAR: -->
<p>See the [[Like clause|description of SOUL patterns]].</p></li>

<li>The optional <var class="term">language</var> argument specifies the language to use. The language argument is handled as follows:
<ul>
<li>If <var class="term">language</var> is omitted, <var class="product">Model&nbsp;204</var> performs the validation in U.S. English (even if the value of the <var>LANGUSER</var> parameter is not US) and lowercase characters are not recognized.</li>

<li>An asterisk enclosed in quotation marks (<tt>'*'</tt>) instructs <var class="product">Model&nbsp;204</var> to use the value of the <var>LANGUSER</var> parameter.</li>

<li>You can enter the name of a valid language enclosed in quotation marks or a %variable containing a valid language. If the value you enter is not supported, the request is canceled with an error message. See the <var>[[LANGUSER parameter|LANGUSER]]</var> parameter for the valid values.</li>
</ul></li>
</ul>
<p>
Without <var>$ChkPat</var>, pattern syntax errors can cause cancellation of the request or require the coding of complex <var>ON</var> units.</p>

==Examples==
<p>
For U.S. English:</p>
<!-- The following example is used in QASHR tests SOUL.DME.263.QAR: -->
<p class="code">%PAT='ABC*'

%X=$chkpat(%PAT)
IF %X NE <nowiki>''</nowiki> THEN
 PRINT %X
 JUMP TO ERROR.RETURN
END IF
</p>
<p>
For French Canadian:</p>
<p class="code">%PAT='p&#234;ch&#233;'

%X=$chkpat(%PAT,'FRENCHC')
IF %X NE <nowiki>''</nowiki> THEN
 PRINT %X
 JUMP TO ERROR.RETURN
END IF
</p>

==Usage notes==
<p>
<var>$ChkPat</var> supports language-sensitive specification of patterns through an optional second parameter (such as <var>[[$Alpha]]</var> and <var>[[$AlphNum]]</var>).</p>
<p>
All characters X'00' through X'FF' are valid in a pattern presented to the SOUL pattern matcher. The <var>$ChkPat</var> function no longer invokes either of the following messages when it encounters these characters.</p>
<p class="code">M204.1688: errortype IN PATTERN 'pattern' AT CHARACTER char

M204.1689: errortype IN PATTERN 'pattern' AT CHARACTER char
</p>

[[Category:SOUL $functions]]