> On 18 Mar 2015, at 21:32, Tom Browder <tom.brow...@gmail.com> wrote:
> On Wed, Mar 18, 2015 at 11:32 AM, Tom Browder <tom.brow...@gmail.com> wrote:
>> On Wed, Mar 18, 2015 at 7:22 AM, Moritz Lenz <mor...@faui2k3.org> wrote:
>> ...
>>> http://doc.perl6.org/language/objects#Object_Construction lists at least two
>>> possible ways. Probably the most interesting one is BUILDALL with a
>>> callsame; see the last example (or example skeleton) in that section.
>
> For my purposes I think the BUILD is best. The BUILDALL method seems
> to put me in limbo as far as the constructed object and using self.
>
> I made a simple class and a driver Perl script:
>
> $ cat T.pm <<HERE_PM
> class T;
>
> has $.a is rw;
> has $.b is rw;
> has $.c is rw;
>
> submethod BUILD(
> # set defaults here
> :$!a = 15,
> :$!b,
Why not set the default here?
:$!b = $!a < 10 ?? 1 !! 0;
> :$!c,
> ) {
> self.set_b;
Then you won’t need this.
> }
>
> multi method set_b {
> if (self.a < 10) {
> self.b = 1;
> }
> else {
> self.b = 0;
> }
> }
Nor this.
> multi method set_b($x) {
> self.b = $x;
> }
Nor this.
> HERE_PM
>
> $ cat T.pl <<HERE_PL
> #!/usr/bin/env perl6
>
> use v6;
> use lib '.';
> use T;
> my $t = T.new;
> say "\$t.a = {$t.a}";
> say "\$t.b = {$t.b}";
> say "\$t.c = {$t.c.defined ?? $t.c !! 'undefined'}";
> $t.set_b(20);
This would then just be:
$t.set(20);
> $t.c = 'defined';
> say "\$t.a = {$t.a}";
> say "\$t.b = {$t.b}";
> say "\$t.c = {$t.c.defined ?? $t.c !! 'undefined'}";
> HERE_PM
>
> $ perl6 T.pl
> $t.a = 15
> $t.b = 0
> $t.c = undefined
> $t.a = 15
> $t.b = 20
> $t.c = defined
Liz
