Re: Access to has_a data from Template?

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On Thu, Sep 16, 2004 at 08:02:16PM +0100, Tony Bowden wrote:
> On Thu, Sep 16, 2004 at 01:39:47PM -0400, Jesse Sheidlower wrote:
> > On Thu, Sep 16, 2004 at 06:30:16PM +0100, Tony Bowden wrote:
> > > On Thu, Sep 16, 2004 at 07:28:52AM -0400, Jesse Sheidlower wrote:
> > > > Suppose I'm looking at a "book", each book being a
> > > > MyLibrary::Book, and each "book" has_a "format"
> > > > (hardcover, paperback, etc.). If I do:
> > > >   [% USE book = Class("MyLibrary::Book") %]
> > > > I still can't seem to get to at the format data:
> > > >   FOREACH format = book.format
> > > > bombs out with
> > > >   undef error - Can't fetch data as class method at
> > > 
> > > Well, of course it will. You're asking for the format of ALL books, which
> > > makes no sense. You presumably want the format of a particular book,
> > > which should be getting passed into the template somehow...
> > No, I want to access a "format" object, to call things on it.
> 
> Which format object? 

One that I will instantiate, if necessary, because it is related
to my book object.

> > The FOREACH was just an example, but in reality, I'd want to 
> > retrieve_all from format, so I can construct a select list
> > (or whatever) from the results.
> 
> Then why are you working with the Book class?

Because the main thing here is that I have a book object, with a
bunch of columns (some of which may belong to other classes
related to book).

> Instead of:
> > > >   [% USE book = Class("MyLibrary::Book") %]
> 
> You should be doing something like:
> 
>   [% USE bookformat = Class("MyLibrary::Book::Format") %]
>   [% SET formats = bookformat.retrieve_all %]
> 
> But really you'd be better off passing this sort of thing into the
> template in the first place.

I thought I was, via my book object. 

Let me put it another way: given that I have a book object,
and that I know book has_a format, is there any way I can get
a format object? Without necessarily knowing that my format
class is MyLibrary::Book::Format? Can I get there from a 
book object?

Thanks. Sorry to be dragging this out.

Jesse Sheidlower