Matt S Trout ha scritto:
Marcello Romani wrote:
I have written a small paragraph that clarifies (I hope :-) why DBIC has
no "stringify_self" method or "Stringify" column group.
This obviously intended for DBIC newcomers coming from CDBI...
------------------------------------------------------------------------
--- FAQ.pod 2006-08-18 13:00:27.000000000 +0200
+++ FAQ_modified.pod 2006-09-07 12:09:23.000000000 +0200
@@ -324,3 +324,43 @@
you ask the resultset for an actual row object.
=back
+
+=head2 Notes for CDBI users
+
+=over 4
+
+=item Is there a way to make an object auto-stringify itself as a particular
column or group of columns (a-la cdbi Stringfy column group, or stringify_self
method) ?
+
+Perl already offers a method to make an object stringify itself, through the
C<use overload> pragma.
+
+Therefore there is no need for a specialized stringification method like
C<stringify_self>.
+
+B<Quick example:>
+
+ use overload "" => sub { $_[0]->name . ", " . $_[0]->address }
+
+
+B<Scenario:>
+
+Suppose we have two tables: C<Product> and C<Category>. The table
specifications are:
+
+ Product(id, Description, category)
+ Category(id, Description)
+
+C<category> is a foreign key into the Category table.
+
+If you have a Product object C<$obj> and write something like
+
+ print $obj->category
+
+things will not work as expected.
+
+To obtain, for example, the category description, you should add this method to the
class mapping the Category table (tipically C<DB::Main::Category>):
+
+ use overload "" => sub {
+ my $self = shift;
+
+ return $self->Description;
+ }
+
+=back
There's already a rather more minimal entry at
http://search.cpan.org/dist/DBIx-Class/lib/DBIx/Class/Manual/Cookbook.pod#Stringification
Maybe merge the better description into the cookbook and create a simpler FAQ
entry that links to it?
Anybody got any better ideas?
I merged the two entries, expanding the cookbook entry and adding a
pointer in the FAQ.
--
Marcello Romani
Responsabile IT
Ottotecnica s.r.l.
http://www.ottotecnica.com
--- FAQ.pod 2006-08-18 13:00:27.000000000 +0200
+++ FAQ_modified.pod 2006-09-07 18:06:37.000000000 +0200
@@ -324,3 +324,13 @@
you ask the resultset for an actual row object.
=back
+
+=head2 Notes for CDBI users
+
+=over 4
+
+=item Is there a way to make an object auto-stringify itself as a particular
column or group of columns (a-la cdbi Stringfy column group, or stringify_self
method) ?
+
+See L<Cookbook/Stringification>
+
+=back
--- Cookbook.pod 2006-08-18 13:00:27.000000000 +0200
+++ Cookbook_modified.pod 2006-09-07 18:02:49.000000000 +0200
@@ -527,10 +527,39 @@
=head2 Stringification
Employ the standard stringification technique by using the C<overload>
-module. Replace C<foo> with the column/method of your choice.
+module.
+
+To make an object stringify itself as a single column, use something like this
(eplace C<foo> with the column/method of your choice):
use overload '""' => 'foo', fallback => 1;
+For more complex stringification, you can use an anonymous subroutine:
+
+ use overload '""' => sub { $_[0]->name . ", " . $_[0]->address }, fallback
=> 1;
+
+B<Example>
+
+Suppose we have two tables: C<Product> and C<Category>. The table
specifications are:
+
+ Product(id, Description, category)
+ Category(id, Description)
+
+C<category> is a foreign key into the Category table.
+
+If you have a Product object C<$obj> and write something like
+
+ print $obj->category
+
+things will not work as expected.
+
+To obtain, for example, the category description, you should add this method
to the class mapping the Category table (tipically C<DB::Main::Category>):
+
+ use overload "" => sub {
+ my $self = shift;
+
+ return $self->Description;
+ }
+
=head2 Disconnecting cleanly
If you find yourself quitting an app with Control-C a lot during
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