[Q] Parser behavior in a string

I noticed that PHP4 accepts and does not raise error (notice messages) for following code. $arr = array('first' => 'one'); $str = "This is first element of array: $arr[first]"; Question: Is this expected behavior that PHP parse w/o errors? If this is not a expected behavior and subject to change, I'm not going to use array w/o ' or " for assoc arrays. Because I log all error messages for production system including notice messages. Thank you. [Note for those who are not familiar with use of {} in PHP] {} can be used to resolve ambiguity not only for arrays, but also for variables in strings. $str = "This is first element of array: {$arr['first']}"; // works as it should. $str = "This is first element of array: $arr['first']"; // parse error. You can use {} for multi-dimensional array and nested objects properties in strings also. i.e. "Text {$obj->foo->var} Text" works like 'Text '. $obj->foo->var .' Text'. -- Yasuo Ohgaki