PHP 4 adds a new mechanism to variable substitution in
strings. You can now finally access object member variables
and elements from multidimensional arrays within strings.
To do so you have to enclose your variables with curly
braces with the dollar sign immediately following the opening
brace: {$...}
To embed the value of an object member variable into a
string you simply write "text
{$obj- member} text" while in PHP 3 you had to use
something like "text ".$obj- member."
text".
This should lead to more readable code, while it may
break existing scripts written for PHP 3. But you can easily
check for this kind of problem by checking for the character
combination {$ in your code and by
replacing it with \{$ with your
favorite search-and-replace tool.