Change 11976 by jhi@alpha on 2001/09/10 12:46:34
Further Class::Struct patching from Damian.
The new new semantics are:
* If you pass an initializer for a nested object, it has to be:
a) a reference to an object of that class, or
b) a reference to an object of a subclass of that class, or
c) a reference to a hash of arguments to be passed to the
class's constructor
* If you pass no initializer for a nested object, the attribute
is initialized to C<undef>
Affected files ...
... //depot/perl/lib/Class/Struct.pm#22 edit
Differences ...
==== //depot/perl/lib/Class/Struct.pm#22 (text) ====
Index: perl/lib/Class/Struct.pm
--- perl/lib/Class/Struct.pm.~1~ Mon Sep 10 07:00:06 2001
+++ perl/lib/Class/Struct.pm Mon Sep 10 07:00:06 2001
@@ -163,10 +163,13 @@
$out .= " \$r->$elem = $init undef;$cmt\n";
}
elsif( $type =~ /^\w+(?:::\w+)*$/ ){
- $init = "defined(\$init{'$name'}) ? \$init{'$name'} : undef";
- $out .= " croak 'Initializer for $name must be $type reference'\n";
- $out .= " if defined(\$init{'$name'}) &&
!UNIVERSAL::isa(\$init{'$name'}, '$type');\n";
- $out .= " \$r->$elem = $init;$cmt\n";
+ $out .= " if (defined(\$init{'$name'})) {\n";
+ $out .= " if (ref \$init{'$name'} eq 'HASH')\n";
+ $out .= " { \$r->$elem = $type->new(\%{\$init{'$name'}}) }
+$cmt\n";
+ $out .= " elsif (UNIVERSAL::isa(\$init{'$name'}, '$type'))\n";
+ $out .= " { \$r->$elem = \$init{'$name'} } $cmt\n";
+ $out .= " else { croak 'Initializer for $name must be hash or $type
+reference' }\n";
+ $out .= " }\n";
$classes{$name} = $type;
$got_class = 1;
}
@@ -416,8 +419,8 @@
=item Class (C<'Class_Name'> or C<'*Class_Name'>)
The element's value must be a reference blessed to the named
-class or to one of its subclasses. The element is initialized to
-the result of calling the C<new> constructor of the named class.
+class or to one of its subclasses. The element is not initialized
+by default.
The accessor's argument, if any, is assigned to the element. The
accessor will C<croak> if this is not an appropriate object
@@ -441,7 +444,8 @@
for a hash is a hash reference.
The initializer for a class element is an object of the corresponding class,
-(or of one of its subclasses).
+or of one of it's subclasses, or a reference to a hash containing named
+arguments to be passed to the element's constructor.
See Example 3 below for an example of initialization.
@@ -521,9 +525,9 @@
initialization is performed instead. Initializers for non-existent
elements are silently ignored.
-Note that the initializer for a nested struct is specified
-as an anonymous hash of initializers, which is passed on to the nested
-struct's constructor.
+Note that the initializer for a nested class may be specified as
+an object of that class, or as a reference to a hash of initializers
+that are passed on to the nested struct's constructor.
use Class::Struct;
@@ -546,6 +550,7 @@
kittens => ['Monica', 'Kenneth'],
markings => { socks=>1, blaze=>"white" },
breed => Breed->new(name=>'short-hair', cross=>1),
+ or: breed => {name=>'short-hair', cross=>1},
);
print "Once a cat called ", $cat->name, "\n";
@@ -556,17 +561,19 @@
=head1 Author and Modification History
-Modified by Damian Conway, 2001-09-04, v0.61.
+Modified by Damian Conway, 2001-09-10, v0.62.
- Removed implicit construction of nested objects.
- This helpfulness was fraught with problems:
+ Modified implicit construction of nested objects.
+ Now will also take an object ref instead of requiring a hash ref.
+ Also default initializes nested object attributes to undef, rather
+ than calling object constructor without args
+ Original over-helpfulness was fraught with problems:
* the class's constructor might not be called 'new'
+ * the class might not have a hash-like-arguments constructor
* the class might not have a no-argument constructor
- * "recursive" data structures don't work well:
+ * "recursive" data structures didn't work well:
package Person;
struct { mother => 'Person', father => 'Person'};
- It is now necessary to pass an object reference to initialize a
- nested object.
Modified by Casey West, 2000-11-08, v0.59.
End of Patch.
