sub x
{
    print "Starting with X\n";
    my $ret = _shared_code(@_);
    return "From X: $ret";
}

sub y
{
    print "Starting with Y\n";
    my $ret = _shared_code(@_);
    return "From Y: $ret";
}

sub _shared_code
{
    # Do stuff here
}

##</code><code>##

sub DoFoo { return do_stuff('Foo', @_) }
sub DoBar { return do_stuff('Bar', @_) }
sub DoBaz { return do_stuff('Baz', @_) }

sub do_stuff
{
    my ($name, ...) = @_;

    # Do stuff here
}