OT: perl function call from a bash script.

[Strong <strong_yethumble pochta ru>]

I have an application that formerly was written in bash but latter got
many scripts being written both in bash and perl. Now I want to use a
function that is contained in a perl-script - that is used by other
perl scripts using 'require' - from a bash script. I need to call it
passing a string to it and get the result from it (a string also).

I've looked through several bash guides but did not find a solution.
So, my question is, How to do that?