Here's another technique which is kind of like a combination of both the dispatch table, as presented elsewhere in this thread, and interpreting the 'ABC' string directly as code. I think it's generally better, especially in an application architecture which is already object oriented.

{
    package Funcs;
    use Carp;

    sub A { print "A!\n" }
    sub B { print "B!\n" }
    sub C { print "C!\n" }
    sub D { print "D!\n" }
    sub E { print "E!\n" }

    sub AUTOLOAD
    {
        our $AUTOLOAD;
        carp "no $AUTOLOAD";
    }
}

# now, wherever $func_com comes from...

Funcs->$_() for split //, $func_com;
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Of course, you may have other ways of parsing $func_com, rather than just by single characters; and other ways of validating it in addition to making the calls and barfing on non-existent methods.