How to implement Variable variable names?

[Christodoulou Demetris]

Hi,
I am writing an application where i have to read from a file variable names and 
variable values.
Is there is a way to use Variable Variables  with the same way used in php?
For example:
$a = "hello";
$$a = "world";
where echo "$a ${$a}";  and  echo "$a $hello";  would output the same.
Thanks in advance,
    Demetris.