[Catalyst] Re: How to access current MyApp instance ?

[Bill Moseley]

On Thu, Jul 05, 2007 at 11:15:57AM -0400, Perrin Harkins wrote:
> For those out there who like TT2's mini-language, I've been using it
> for many years without ever encountering any of the problems described
> in this thread.  I never add any variables to the stash from inside my
> templates (temporary loop variables excluded), avoid MACRO (I only use
> PROCESS), and generally keep the templates  very, very simple.  And I
> have documentation that describes the data structure that will be in
> the stash for each page.

Do you avoid macros because the localization hit or because of the
namespace issues?  I don't normally have that many items in the stash
(or macros) so namespace collision is not a concern.

> Templates aren't normal code (even with in-line perl) and they don't
> handle complexity like real code does, so you have to control your
> impulse to turn them into thousands of little components.  It just
> gets too confusing.

Thousands, for sure.  A small handful can really help.  It's not so
much to do something better done in Perl, but as a way to avoid
writing the same markup over and over.  A real plus when you want to
change a common page element on the entire site sometime down the
road.


WRAPPERs are the biggest gem for getting out of that top-down approach
to page design that lends itself to markup duplication.  WRAPPERs can be
confusing at first, but they are not that hard to get used to.

Likewise, a few macros can help.  Abstracting out common elements is
useful in Templates as it is elsewhere in the code you write.

Say you have a site with a large number of tables and they all should
look similar.

Each table has click-able headings and displays a page of rows with
alternating even/odd-style, and pager links (Previous 1 2 3 4 Next).

Those are all display items -- belongs in the View.

How would you generate the <th> links that show which is the currently
sorted column and an indicator if it's sorted ascending or descending?
Obviously, that code should only be done once.


I just want to be concerned with the data that's unique for the page
I'm generating.  So, for the <th> example, I set up a block like this
where the table_headings_link() macro adds in all the markup for
creating the click-able headings and creates the correct
self-reference URL (as the table might already be limited by, say, a
query string).


[% BLOCK table_headings %]
<tr>
    <th>
        [% table_heading_link( 'Name', 'name', ) %]<br />
        [% table_heading_link( 'Account', 'account', ) %]
    </th>
    <th>
        [% table_heading_link( 'Email', 'email', ) %]
    </th>

    <th>
        Status
        [% table_heading_link( 'Active', 'active' ) %] /
        [% table_heading_link( 'Admin', 'admin' ) %]
    </th>
</tr>
[% END %]

You could do this:

    <th>
        [%
            PROCESS table_heading_link
                label = 'Name',
                sortby = 'name';

            '<br />';

            PROCESS table_heading_link
                label = 'Account',
                sortby = 'account';
        %]
    </th>

But I think the macros help with readability.


In the past I've abstracted that out even more (since the <tr> and
<th> is common on every page -- but that's a bit overkill.

-- 
Bill Moseley
moseley at hank.org