<?
$a['a']=1;
$a['b']=1;
$a['c']=1;
$str="function a(){global \$a;if(\$a['a']==1 && \$a['b']==1 && \$a['c']==1){return 'OK';}else{return 'ERR';}}";
eval($str);
if(a()=="OK"){
 echo "GOOD";
}else{
 echo "OH NO";
}