Perl time:

sub AUTOLOAD {
    our $AUTOLOAD=~s/.*:://;
    no strict;
    local $_=$_[0] and *STDOUT->$_($AUTOLOAD)
}

HelloWorld("print");

Pro: You can Give HelloWorld any (syntactically valid) name you like and (as long as the parameter is "print", anyway) its name will be printed, no pre-declaration required.

Con: The specified function inside the quotes has to be a method associated with a file descriptor.