Newbie question about string(passing by ref)

[lazy]

Hi,

I want to pass a string by reference. I understand that strings are
immutable, but Im not
going to change the string in the function, just to aviod the overhead
of copying(when pass-by-value) because the
strings are long and this function will be called over and over
again.
I initially thought of breaking the strings into list and passing the
list instead, but I think there should be an efficient way.

So is there a way to pass a const reference to a string?

Thanks