On Thu, Sep 25, 2008 at 12:08:31AM -0700, Christopher Brown wrote:
> For instance, I can use *has "+..."* to change the properties of
> attributes. I can use *traits* to change the properties. And I can use
> roles to make reusable attributes. But there does not seem to handle
> generic attributes. And rename_attribute (and other functions) seems like
> one allow generics and seems like missing functionality.
Er. rename_attributes as you described it is completely irrelevant to this
problem. You'd've done better to start with the -actual- problem, which I'll
speak to below.
> I am pretty tired of writing attribute specifications. All my attributes
> are essentially the same. They are dates, they are filenames, they are
> strings, they are names, they are directories. My perl programs are
> littered with *has* *=>* definitions. That are often repeated.
Moose does already support
has [ qw(...) ] => (...);
as an alias for
has $_ => (...) for qw(...);
> The good
> programmer in me says that I should put these reusable codes in modules and
> release them on CPAN. My hopes is to put these common attributes into a
> Moose Role and use them with some construct like:
>
> with Attributes( date, name );
>
> The catch is that the attributes, though providing the same functionality
> based on the Type, do not always have the same name. I often want an API to
> have attributes with different names. "Date" might be "begin_date" or
> "name" might be "last_name" for instance.
So what you want is for the method aliasing stuff that already exists in
roles to be extended so you can alias attributes on application as well?
Now -that- seems like a useful feature, though I don't think it's actually
what you want. Stevan, Dave, thoughts?
> But I much rather say something like
>
> with Attributes( infile => "file", outfile=> "file" )
This smells like either the above, or parameterised roles. However ...
> I suppose one solution would be to create a module that returns the
> definition of the attribute rather than the attribute itself
>
> use MooseX::Common::Attributes;
> my $mca = MooseX::Common::Attributes->new;
> has qw(infile, outfile) => $mcs->file;
>
> But that gets uglier.
Well, only because you intentionally made it ugly.
Instead, I think what you really want it one of
(1) export attribute declarators, so -
use MooseX::Attributes::File qw(has_file);
has_file 'infile';
has_file 'outfile';
(2) an attribute metaclass that provides what you want as defaults
has 'infile' => (metaclass => 'File');
has 'outfile' => (metaclass => 'File');
--
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