Ed am Montag, 10. April 2006 20.56:
> I'm trying to use the Class::Struct to create some C-Like structs but
> I'm unable to dereference any array elements in the struct. I'm
> admittedly a Perl newbie trying to map my C programming experience
> into Perl so it's possible I'm "thinking in C" rathern than in Perl.
> I've referenced several texts and web references on the subject and
> get several ways to create a structure. In each case I'm unable to
> access any elements in the structures once they are initialized.
Hello Ed,
> Here is an example taken straight out of Programming Perl (3rd ed) :
# Always a good idea, even if it compiles without use strict:
use strict;
use warnings;
> use Class::Struct;
>
> struct Manager => { # Creates a Manager->new() constructor.
> name => '$', # Now name() method accesses a scalar value.
> salary => '$', # And so does salary().
> started => '$', # And so does started().
> };
>
> struct Shoppe => { # Creates a Shoppe->new() constructor.
> owner => '$', # Now owner() method accesses a scalar.
> addrs => '@', # And addrs() method accesses an array.
> stock => '%', # And stock() method accesses a hash.
> boss => 'Manager', # Initializes with Manager->new().
Above comment is misleading: The lines does not initialize a new object (you
have to instantiate an object yourself, see below); it installs a check that
the object's attribute is of the Manager class.
> };
>
> $store = Shoppe->new();
my $store = Shoppe->new();
> $store->owner('Abdul Alhazred');
> $store->addrs(0, 'Miskatonic University');
> $store->addrs(1, 'Innsmouth, Mass.');
> $store->stock("books", 208);
> $store->stock("charms", 3);
> $store->stock("potions", "none");
# add:
$store->boss(Manager->new);
> $store->boss->name('Prof L. P. Haitch');
> $store->boss->salary('madness');
> $store->boss->started(scalar localtime);
>
>
> print "owner: $store->owner";
This won't print what you want: $store is interpolated, and '->owner' is taken
literally.
print 'owner: ',$store->owner, "\n";
#or:
#print "owner: @{[ $store->owner ]}\n";
> $someowner = $store->owner;
my $someowner = $store->owner;
> print "owner: $owner";
>
> print "addrs: $store->addrs";
The same holds here, plus the method returns an arrayref, not an array
print 'addrs: ', (join ', ', @{$store->addrs}), "\n";
> @some_addrs = $store->addrs;
my @some_addrs = join ', ', @{$store->addrs};
> print "addrs: @some_addrs";
my @some_addrs = join ', ', @{$store->addrs};
# Output:
owner: Abdul Alhazred
owner: Abdul Alhazred
addrs: Miskatonic University, Innsmouth, Mass.
addrs: Miskatonic University, Innsmouth, Mass.
hth!
Dani
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