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educated_foo (3106)
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Journal of educated_foo (3106)
Defining "DSL", or eternal recurrence in software
I want a function to take the mean of some data:
$x = mean \@data;
Hm.... I want to ignore NaN and Inf sometimes; I'll add a flag for it:
$x = mean \@data, 1;
But I may also want to trim outliers; I'll use keyword arguments:
$x = mean \@data, skipinf => 1, trim => 0.1;
Whoa, this is getting complicated; I'll make it an Object:
$x = new Mean(@data);
$x->{skipinf}=1;
$x->{trim}=0.1;
$y = $x->value
OMG, no encapsulation, I'll make accessors:
$x = new Mean;
$x->setData(\@data);
$x->setSkipInf(1);
$x->setTrim(0.1);
$y = $x->value
But now I have to do this just to do a simple mean:
$x = new Mean;
$x->setData(\@data);
$y = $x->value
I know, I'll create a little language for means:
$x = mean \@data, trim => 0.1, skipinf => 1;
Then I can write in the domain terminology, and taking the mean is easy:
$x = mean \@data;
...and thus we see how "writing interfaces that don't suck" became "creating little languages."
help them think they understand.
--Larry Wall
I don't get the set_method things (Score:1)
But it seems to me that 90% of the time, you don't really NEED the ability to mutate the objects after creation time, especially with that sort of thing. You'd almost always set it at creation time.
Mutators just adds more (potentially illogical) states (and thus potential bugs).
$mean = Mean->new( skipinf => 1, trim => 1 )->on( @data );
package Mean;
use Object::Tiny qw{
skipinf
trim
};
sub o
Re: (Score:1)
Blah->new(@stuff)->doit. There's always at least one in the CPAN queue -- see Sudo this morning. Doing this is almost always a mistake indicative of someone having been told that "objRe: (Score:1)
Sometimes, yes. And it's true people get bitten by the object fad.
But as you scale is can be very advantageous to have the option of encapsulating a function and moving it around.
It's not really safe to do this with a raw code-ref, because a coderef could be anything at all and is tied to the Perl instance. A data structure is far more flexible.
"Process Objects" (objects that describe a computational process) allow you to do things that functions can not do.
For e
Re: (Score:1)
IMHO they get the defaults wrong most of the time. If you amortize over all the people using a module, it's less trouble for those who need them to go through the full pain of either serializing functions through e.g. Storable or doing a custom solution, than for everyone to use a ghastly "OO" interface, or roll their own. Distributing a module on CPAN is a real win when it will save time
Re: (Score:1)