accessing a constant which name is stored in a variable

Would it make sense to add the ability to access constants through a function or syntax where the constant name is stored in a variable? I tried a few methods, but I think it isn´t possible: define('my_constant',TRUE); $c_name='my_constant'; echo $$my_constant; // sure, does not work echo {$my_constant}; // does not work either well, then I had in mind to add a statement/function that returns the value of a constant as follows: (mixed) get_constant( (string) constant_name ) I hope I did not miss a very simple way... andré