Larry Wall writes:
>
> I guess the real question would be, is it an overall simplification to
> allow "has" anywhere? There *is* an object out there representing each
> abstract closure (pre-instantiation), but it's a bit of a stretch from
> "Every block is a closure" to "Every block is a closure that is also
> an object except that the object in question doesn't participate in
> the closure's closure, as it were."
>
> On the other hand, it's the block itself that is that abstract
> pre-closure object, so running it the other way would mean stretching
> our minds into thinking "has" always sets block properties, and that
> every object is a funny kind of block.
>
after reading this I realize that current meaning of "has" is really
quite strange... I would rather call it "serve" ( see below )
one can think of class / object attributes in the following way (
soryy, may be its too handwaving, but I have in mind plan9 notion of
every process having its own vision of the namespace , ( and every
block / closure in perl is sort of process ) ) :
class attributes : persistent lexical variables .
Class serve the same copy of it to all its
subs/methods
object attributes : persistent lexical variables .
Class _multiplexes_ them to each
object and each object have its own private instance of it .
so class is in some sence a server of a ( lexical ) namespace .
Class Foo {
has $foo ; # persistent lexical variable -- class attribute
serve $bar; # every instance of Class Foo will have its own private
# version of $bar -- object attribute
# or may be this.
multiplex $bar; # but this is longer
...
}
so now it is clear _who_ "has" and "serve" : the surrounding block (
marked by "Class Foo" ) _has_ ( persistent ) $foo lexical and it _serve_
private $bar instance to each object .
since its all about ( lexical ) namespaces ...
method "new" return an object to which class serve a private
copy of all variable marked by "serve" ( or multiplex ??? )
I dont know how classes and objects work now inside , but probaly
in the spirit of "class is just ...." any block which have some sort
of label / mark ( and Class Foo is just one of that kind ) may have a
"new" method . in that case the thing returned have private copyes of
variables labeled by "serve" and access to all "has" variable and
methods/subs defined inside.
counter: {
has $a;
serve $.cnt;
my sub count(){ .cnt++ }
my sub new() {
$a++ ; # a counter of counters
ret new counter ; # this a default "new" method
}
}
$x = counter.new ;
$x.count ;
just ( veryy fuzzy ) thoughts ...
arcadi
