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