Re: Set attribute using 'after'

On 05/11/2012 05:53 PM, Karen Etheridge wrote:
> On Fri, May 11, 2012 at 03:42:15PM +0200, Emmanuel Quevillon wrote:
>> package Myclass;
>>
>> use Moose;
>> extends 'SuperClass';
>> with 'MyRole';
>>
>> has 'file' =>  (is =>  'rw', isa =>  'Str', required =>  1);
>> has 'fh'   =>  (is =>  'rw', isa =>  'FileHandle');
>>
>> after 'new' =>  sub {
>>     my $self = shift;
>>     my $file = $self->file();
>>     $self->set_fh($self->open_file($file)); # Returns a FileHandle obj
>>     return 0;
>> };
>>
>> 1;
>
> Why not just create the filehandle when it's first needed, rather than at
> construction time?  (that is: let the attribute build itself, rather than
> explicitly calling a setter).
>
> has fh =>  (
>      is =>  'ro', isa =>  'FileHandle',
>      lazy =>  1,
>      default =>  sub {
>          my $self = shift;
>          $self->open_file($self->file);
>      },
> );
>
> or, you can skip the extra attribute entirely by using library code:
>
> use MooseX::Types::Path::Class qw(Dir File);
> has file =>  (
>      is =>  'ro', isa =>  File,
>      coerce =>  1,
> );
>
> # later, in other code...
> # $self->file isa Path::Class::File
> my $fh = $file->openr;
>
> # or skip using the fh directly...
> my $contents = $self->file->slurp;
>
> my $filename = $self->file->stringify;
>
> # etc etc...
>
>
Thanks Karen, I think I'll change for MooseX::Types::Path::Class

Thanks to all
Regards	

-- 
-------------------------
Emmanuel Quevillon
CIB, Centre Informatique pour la Biologie
Institut Pasteur
+33 1 44 38 95 98
tuco at_ pasteur dot fr
-------------------------