Haha, that will teach me for trying to golf on public mailing lists.
It should actually read:
sub int2vec ($n) {
+<<(sprintf("%b",$n).split('')); # now I'm just golfing :-D
}
unless you only ever want to use it with the number 7.
-db.
----- Original Message ----
From: David Brunton <[EMAIL PROTECTED]>
To: perl6-users@perl.org
Sent: Thursday, October 5, 2006 4:01:34 PM
Subject: Re: Operator overloading/Inheritance from built-in types?
Hopefully the following will help. If I've missed the thrust of your
questions, feel free to disregard while someone else improves on my
answer :) I only overloaded the infix:<+> operator, but it should give
you an idea.
I would write the class comme ça:
use v6-alpha;
class Register {
has @.reg; # since it's list-ish anyhow
has $.dec;
submethod BUILD (:$.dec) {
@.reg = int2vec( $.dec ); # new() calculates reg
}
multi sub *infix:<+> (Register $self, Int $n) {
return $self.dec + $n;
}
sub int2vec ($n) {
+<<(sprintf("%b",7).split('')); # now I'm just golfing :-D
}
}
my Register $vec .= new(:dec(7));
say $vec.reg;
say $vec.dec;
say $vec + 2;
I don't think I get much extra credit, but this should give you the
infix operator and the new() behavior you're looking for.
Also, your int2vec is faster. I just wanted to use sprintf("%b",7) so
I could mention again how I wrote it.
hee hee.
-db.
--- Wim Vanderbauwhede <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I want to create a kind of bitvector object. Ideally, I'd like to
> inherit
> from Array and then overload [],=, +,- etc.
> I tried to overload the '+' operator, but I can't get it to work as a
> method. Also, I'd like to overload the assignment operator.
> Is that at all possible?
> Below is my attempt, with the ideal solution and the received errors
> in
> comments.
>
> Any suggestions?
>
> Thanks,
>
> Wim
>
> ------
> use v6;
>
> my $vec=Register.new(dec=>7);
> # my $vec=Register.new(7);
> # or even better:
> # my Register $vec=7;
>
> say $vec.reg;
> # say vec[]; # undefined!
> # new() should calculate reg. But how?
>
> say $vec.dec;
> # say $vec;
>
> $vec.write(29);
> # $vec=29;
>
> say $vec.read(2,4);
> # say $vec[2..4]
>
> say $vec.read(3);
> # say $vec[3]
>
> say $vec.add(5);
> # say $vec+=5; # *** Cannot cast from VObject (MkObject {objType =
> (mkType
> "Register") ... to Double (VNum)
>
> # say $vec + 5; # *** No compatible subroutine found: "&dec"
>
> #----
> class Register {
> has $.reg;
> has $.dec;
>
> method write ($self: $n) {
> $self.dec= $n;
> $self.reg= int2vec($n);
> }
>
> method read ($self: $i,$j=$i) {
> return $self.reg[$i..$j];
> }
>
> method add ($n) {
> $.dec+=$n;
> $.reg = int2vec($.dec)
> }
>
> # This doesn't work: *** Missing invocant parameters in '&infix:+': 0
> received, 1 missing
> # method infix:<+> ($self: Int $n) {
> # $self.add($n);
> # }
>
> sub int2vec ($n,$v=[]) {
> if ($n > 1) {
> if ($n % 2) {
> int2vec(($n-1)/2,[1,@$v]);
> } else {
> int2vec($n/2,[0,@$v]);
> }
> } else {
> return [$n,@$v];
> }
> }
> }
>
> #sub infix:<+> (Register $self, Int $n) {
> # return $n+$self.dec;
> #}
>
> #sub infix:<+=> (Register $self, Int $n) {
> # $self.add($n);
> #}
>
> --
> If it's pointless, what's the point?
> If there is a point to it, what's the point?
> (Tibor Fischer, "The Thought Gang")
>
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