Simple Subroutine Question

walkingthecow has asked for the wisdom of the Perl Monks concerning the following question:

I have a subroutine that has two parameters: username and password. I would like to setup that subroutine so that it accepts both methods of parameters, meaning foo(user=>$user, pass=>$pass) AND it could also accept foo($user,$pass)... Here is what I have (it accepts user=> and pass=> args:

sub ssh_connect {
    my ($self,%args) = @_;
    my $user = $args{user};
    my $pass = $args{pass};
      
    print "$user and $pass\n";
}
[download]

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Re: Simple Subroutine Question by tilly (Archbishop) on Aug 01, 2009 at 00:53 UTC
I would strongly recommend only accepting one form. If you want to accept both, have 2 different functions. That way if you ever want to add a third argument or fourth argument (such as, oh, a machine to connect to, a port, options for an SSH tunnel, etc) you'll be in good shape. If you disregard said advice, you could do it as follows: `sub ssh_connect { my ($self, $user, $pass) = @_; if (3 < @_) { (undef, my %args) = @_; $user = $args{user} or confess("No user"); $pass = $args{pass} or confess("No pass"); } print "$user and $pass\n"; }` [download] Alternately you could make the two forms be `$foo->ssh_connect($user, $password); $foo->ssh_connect({user => $user, pass => $password});` [download] and dispatch on whether there are fewer than 3 arguments. This is actually a saner way to go, but it does require {}.	[reply] [d/l] [select]
Re^2: Simple Subroutine Question by walkingthecow (Friar) on Aug 01, 2009 at 01:00 UTC
If choosing between the two, what do the PerlMonks suggest is a better way of doing this? I'd like it to be EASY to write and EASY to read... So, I was thinking the user=> would be good, but there are MANY functions in this bad boy and not sure if I should have them all use that method... An example of a lot of arguments is below: foo->adduser(id=>$id, uid=>$uid, prgrp=>$pgrp, sgrps=>$sgrps, gcos=>$gcos, expire=>$expire)... I mean, is that ridiculous??	[reply]
Re^3: Simple Subroutine Question by tilly (Archbishop) on Aug 01, 2009 at 01:13 UTC
The more arguments there are, the better the argument gets for passing a hash and getting named arguments. Because readability matters. For processing those arguments I'm still happy with the method I gave at Re (tilly) 2: passing subroutine arguments directly into a hash.	[reply]
Re: Simple Subroutine Question by AnomalousMonk (Archbishop) on Aug 01, 2009 at 02:13 UTC
See also the extensive discussions of Preferred technique for named subroutine parameters? and Named Subroutine Parameters: Compile-time errors vs. Run-time warnings. My own strong preference is for the `function({ foo => 42, bar => 'baz' });` form. Others will disagree.	[reply] [d/l]