1<documentation title="Lowercase Built-In functions">
2    <standard>
3    <![CDATA[
4    All PHP built-in functions should be lowercased when called.
5    ]]>
6    </standard>
7    <code_comparison>
8        <code title="Valid: Lowercase function call.">
9        <![CDATA[
10if (<em>isset</em>($foo)) {
11    echo $foo;
12}
13]]>
14        </code>
15        <code title="Invalid: isset not called as lowercase.">
16        <![CDATA[
17if (<em>isSet</em>($foo)) {
18    echo $foo;
19}
20]]>
21        </code>
22    </code_comparison>
23</documentation>
24