Ok, I'll make up an example to explain why I'd like named parameters...pardon syntax errors, this is all untested. There *will* be syntax errors. Also, please don't study my problem space too much, as I'm just coding up a random example out of my head. I'm not actually coding a Chess program -- it's a generic question. You should see, though, from this example that I am not going after "HashesThatDoStuff", exactly, but rather something else stylistically.

Rationale for named parameters -- One of the things I often don't like about OO sometimes is that parameter order matters. When folks put more than a few methods in a constructor, it's rarely obvious which is which. So named parameters (as in, say, Python? Others?) allow the code to be a bit more readable. 

my $board = ChessBoard->new('start');
my $game = GameState->new(
   -white => ChessPlayer->new(
                 -board => $board,
                 -controller => Human->new(
                     -name => 'Larry',
                     -coffee => 1,
                 ),
             ),
   -black => ChessPlayer->new(
                 -board => $board,
                 -controller => Computer->new(
                      -level => 5,
                      -ply => 3,
                      -timecap => 60,
                      -style => 'Nimzovitch',
                 ),
             ),
   -board => $board,
   -rules => new ChessRules('suicide'),
);

[download]

In the above example, timecap, ply, and level are all numbers, but I can easily tell them apart by the names, without having to know the order of the parameters as required. If I get the order wrong, it won't matter.

I'll admit the example above is contrived (I wouldn't normally construct my entire object model in one statement), but it shows what I'm getting at.

My OP question was, essentially, what are better ways to implement the above goal in Perl? How can we do this without creating mammoth constructors, yet still support inheritance and so on? MethodMaker will go a ways to keeping from writing accessor boilerplate and variable declarations, but constructors...that's the hardest part to keep elegant.

Thanks to everyone for the help and insight though. This is very good help for someone who is experienced in OO but still not quite getting it to come out elegantly in Perl. Appreciate it.

In reply to Re: Re: Re: Re: Reducing Perl OO boilerplate by flyingmoose
in thread Reducing Perl OO boilerplate by flyingmoose

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