# from Adam Kennedy
# on Monday 05 March 2007 02:30 am:
>The problem is it's not self-contained, it requires much more
> additional state to be held, and far more additional checking.
True, it is not self-contained, but how would the nested approach go
core?
cc_author: 0
...
extensions:
cc_author: 'identify what you mean by it here'
The actual data of interest is simply:
$meta->{cc_author}
You have to look out for collisions, or at least go to the trouble to
overwrite it in both places. But, for promoting extensions to core
status, your code looks the same.
extensions:
'identify what you mean by it here':
cc_author: 0
that's
$meta->{extensions}{'identify what you mean by it here'}{cc_author}
And it means that code for cooperating/competing extensions is more
complicated:
my $ext = $meta->{extensions};
my $cc_author =
exists($ext->{"joe's implementation of cc_author"}) ?
$ext->{"joe's implementation of cc_author"} : (
exists($ext->{"jill's cc_author attempt"}) &&
$ext->{"jill's cc_author attempt"}
);
Ugh. Let's try it the other way while simultaneously adding features.
if($meta->{'meta-spec'}{version} > 1.5) {
# pretend all three are compatible as far as we're concerned
my %supported = map({$_ => 1}
"joe's implementation of cc_author",
"jill's cc_author attempt",
"http://www.nntp.perl.org/group/perl.qa/2007/03/msg8032.html',
);
my $type = $meta->{'meta-spec'}{extensions}{cc_author};
$supported{$type} or return;
}
my $cc_author = $meta->{cc_author};
>More things can go wrong and the implementation would thus be more
>complicated.
Some guy once said something about "as simple as possible, but no
simpler."
Again, the data of interest is a top-level key and the path to it
doesn't change when it goes core. Even the most naive of
implementations would do the right thing 95% of the time.
>And it's more wordy and more complicated that the other way
I think it is less wordy because the extension identifier is not the key
name. Also, when the extension goes core, all of the tools that are
using it are able to be automatically in sync with no added code.
# and on Monday 05 March 2007 06:28 am:
>And it creates a sort of DMZ and testing ground for features, before
>they most to the core.
What's the migration path for the
$meta->{extensions}{"my big long identifier"}{key_of_interest}
code? And how long will it take for tools to catch-up after this
mosting of which you speak?
I think it's better to just make sure that it has a hall pass than to
lock it in the closet.
--Eric
--
"Unthinking respect for authority is the greatest enemy of truth."
--Albert Einstein
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