--- Dave Whipp <[EMAIL PROTECTED]> wrote:
> "Damian Conway" <[EMAIL PROTECTED]> wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> >Anything that "holds" anything is a variable, not a value.
> > [...]
> > I'm saying that only scalar *values* can have C<but> properties.
> > And yes, that includes Array references, but not arrays.
> >
> > > My mental image is of variables
> > > that provide access to values: variables are compile-time, and
> lexically
> > > scoped: values are run-time, and (can be) dynamically scoped.
> >
> > Not quite. Variables are containers, values are the data they
> contain.
> > Compile-time/run-time and scoping are orthogonal to that.
>
> OK, I've assimilated all that (though it still feels wrong). I think
> you are
> saying that of the following, the 4th is an error.
>
> my @a is Foo = @x;
> my $b = [@x] but Foo;
> my $c = @x but Foo; # ArrayRef automagically created
> my @d = @x but Foo; # error: no values involved in this assignment
> my @e is Foo := @x;
>
> I think that the thing that confused is that C<is> Vs C<but>
> distinction was
> introduced as compile-time vs run-time. It seems that this
> distinction is
> not relevant.
>
> Lets see if I apply this to objects. Objects are variables (they
> contain
> attributes). All access to objects is via (scalar) references: these
> references, being values, can have C<but> properties. When a method
> is
> invoked on an object, that method has an invocant, which enables the
> method
> to see the C<but> properties on that reference. If an object wants to
> have
> properties that apply to all references (to a given instance), then
> that
> property must be defined as an attribute of the object. An instance,
> itself,
> doesn't have postIt style properties.
I'll ask, since I don't know: What's the access syntax for these
things?
my $i is wooly;
How do I test for wooliness? if ($i.wooly) { print "Booly!"; }
my $i = 6 but wooly;
How do I test for wooliness? if ($i.wooly) { print "Booly!"; }
class Mammoth {
member Boolean wooly;
};
my Mammoth $i;
if ($i.wooly) { print "Booly!!"; }
Is this right?
I ask this because I can easily see wanting a class behavior that
attaches value properties, such as "but true". This might almost become
a standard idiom, as:
my HideousDatabaseConnection $hdc = new HideousDatabaseConnection(...);
die "Hideous Death"
unless $hdc;
Where the ctor would ensure that but true/but false was set.
(Welcome to 1977. K&R, anyone?)
=Austin
=Austin
