For me, objects are state-keepers. Methods may cause the object to change state, or they may be used to interrogate the object about its state (or both). How to object keeps its state however, is something only known the the class(es) of which the object is an instance.

Abigail

Granted, a.b = 12; is much nicer looking than a.set_b(12); or a.set_b = 12

Granted, a.b = 12; is much nicer looking than a.set_b(12); or a.set_b = 12
(Other post: If it's supposed to be an assignment it should look like an assignment, and setting a property or attribute is an assignment no matter how it's mediated under the hood.)

FYI, in case you didn't know about it already, Attribute::Property makes a->b = 12 work in Perl 5. From its synopsis:

my $object = SomeClass->new(digits => '123');

$object->nondigits = "abc";
$object->digits    = "123";
$object->anyvalue  = "abc123\n";

$object->anyvalue('archaic style still works');

my $john = Person->new(name => 'John Doe', age => 19);

$john->age++;
printf "%s is now %d years old", $john->name, $john->age;
[download]

When modifying a value using an accessor method (which we dubbed 'archaic style'), things get ugly:

Old:
$john->age($john->age + 1);
$john->name->(do { (my $n = $john->name) =~ s/Doe/Smith/; $n });

New:
$john->age++;
$john->name =~ s/Doe/Smith/;
[download]

Having these things¹ built-in in Perl 6 will make me happy.

Juerd # { site => 'juerd.nl', plp_site => 'plp.juerd.nl', do_not_use => 'spamtrap' }

¹ The things that are called 'properties' in Perl 5 jargon², but 'attributes' in Perl 6 jargon. Perl 5's 'attributes' are 'traits' in Perl 6. (IIRC)
² But not officially. They're often called 'attributes', but we should discourage that, because 'attributes' are already something else. Attributes are relatively new, though, so we can't blame writers of older documentation.

...but not as nice as a->set_b(12). :-)
...I know, I know arrow notaion is going away in Perl6. :-(

You seem disappointed that the arrow notation is going away. Personally, I think this is a Good Thing. Aside from the fact that it will mean less typing for common things, it's a holdover from the old days of C. In C, a struct's members could be accessed with dot notation:

  typedef struct {
      double x
      double y;
  } POINT;

  POINT some_point;

  /* and later in the code */

  some_point.x = 1.02;
[download]

However, if you later had passed a pointer to a struct, you would access the struct members with arrow notation:

  some_point->x = 1.02

Since Perl was largely designed to be familiar to C programmers, having an arrow to dereference things seemed fine. However, Perl 6 seemingly is intended to be familiar to a larger audience (in some ways), it makes sense to drop the C style arrow notation in favor of the dot notation that popular languages use.

And just to keep things topical, by using the arrow notation, we may be encouraging C programmers to use objects like structs and that's just silly. Which is kind of the point of much of this thread :)

Cheers,
Ovid

New address of my CGI Course.

Nah. a[insert method call punctuation here]set_b(foo) is just nasty. If it's supposed to be an assignment it should look like an assignment, and setting a property or attribute is an assignment no matter how it's mediated under the hood.

One of the few places (well, OK, the only place so far, but I won't rule out others existing) that I like lvalue methods or subs.