If you want named parameters, I'd suggest using the first method. If you want to operate on data stored in a hash, pass a hash ref. I don't like the idea of using a hash reference to pass in named parameters because the calls will mostly have those ugly additional braces.

I think a better question might be, "when should I use named parameters?"

My thoughts on that are that they should only be used where the parameters in question set features of a fairly complex datatype. Some examples:

my $shape  = Box->new(length=>10, width=>5, height=>3); # might make s
+ense.
my $string = SuperString->new(text=>"foobar");          # probably doe
+sn't.
my $substr = mysubstr(Search=>"bigbigstring",For=>"big", Occurence=>2)
+; # UGLY!
[download]

I've actually seen interns, apparently far too impressed with CGI.pm, write code like the third example. Please don't.

-sauoq
"My two cents aren't worth a dime.";

my @people = People->search( position=>'manager', last_name=>'Smith' )
+;
[download]

my @people = People->search('position', 'manager', 'last_name', 'Smith
+');
# or 
my @people = People->search({ position=>'manager', last_name=>'Smith' 
+});
[download]

I like the first way for a few reasons: first, when using a hash as opposed to an array, the relationship between the pairs of parameters is very clear. Clearly position and 'manager' are related items in this method call. This is less clear in the array version. Also, I like being able to have barewords with the hash version -- less quotes I have to type. And no curly braces like in the hashref 3rd version.

This method makes more logical sense to me, and is easiest to type. However, I would probably use a hashref if the named parameters were combined with unnamed parameters, such as:

$x->text('hello world', { font=>'arial', size=>'12px' });
[download]

... just so I could visually separate the "important" data from the less-important formatting arguments.

All in all, it's probably more important to stive for consistency than which specific style you choose. Having said that, most of the methods I encounter are not good candidates for named parameters, as in the above substr() example by sauoq

But I never use the hashref method to pass in parameters. It's ugly, pointless and just adds punctuation without any gain.

I also like to use local %_ = @_ to put the named parameters in a hash.

Abigail

It's ugly, pointless and just adds punctuation without any gain.

I think I mostly agree with that statement. However, I would also tend to think that passing in 1 hashref vs. 2*n parameters would be more efficient in some situations...mainly if the hashref of opts you pass in will also get forwarded into an internal serializer class method(s) or some such foo.

Now granted, you could just pass \%args, and the performance difference is probably not measureable so it's all a matter of taste again I guess.

I agree, it's ugly and pointless on a ->new( {option1=>'on'} ) call, where there is no strict set of parameters, just 'options', but on a class method, I would think it more desireable ->dostuff('param1', {option1=>'on', option2=>'0'}).

-=Chris

I think I mostly agree with that statement. However, I would also tend to think that passing in 1 hashref vs. 2*n parameters would be more efficient in some situations...mainly if the hashref of opts you pass in will also get forwarded into an internal serializer class method(s) or some such foo.

You mean, compared to the overhead of actually calling a sub? You'll have to create a far fetched example to make a significant difference. And there's of course always &func;.

I agree, it's ugly and pointless on a ->new( {option1=>'on'} ) call, where there is no strict set of parameters, just 'options', but on a class method, I would think it more desireable ->dostuff('param1', {option1=>'on', option2=>'0'}).

This confuses me. The first one suggests it's a constructor, and constructors often are class methods as well. So why is a hashref ugly in the first example, but more desireble in the second? (For me, they all subs - whether they are used as methods (either class or object) or not).

Abigail

edited: Mon Aug 19 23:26:50 2002 by jeffa - closed ul tag

Damn disgraceful. I be a webb devloper n stufs.
Sorry about that.

-=Chris