Well, you could reduce it to one line, and hide that line in another helper sub, I suppose. This method relies on the fact that if a sub is called with an '&' and without an explicit parameter list, it inherits @_ from its caller (see perlsub).

use strict;
use warnings;

package TestClass;

sub _has_params {
    return @_ > 1 ? scalar(@_) - 1 : 0;
}


sub mytest {
    die "@_\n" if &_has_params;
    print "We're ok.\n";
}

1;

package main;

print "Testing with no parameters.\n\t";
TestClass->mytest( );

print "Testing with one parameter.\n\t";
TestClass->mytest( "Hello" );
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There is one trick though, and I'm sure you're already dealing with it somehow: When a sub is called as a method (be it a class method or an object method) it will have one parameter passed into @_; either the class name or the self object ref. That's why in my "has_params()" subroutine, I only trigger a positive if there is more than one parameter.

When you run the snippet above you'll see that it passes the first test, and dies on the second one.