[Bioperl-l] Bio::Root::RootI->throw($msg,$class) overloading?

[Chris Fields]

I suppose you could; Bio::Root::Root does that using Error.pm (if it  
is installed).  It almost sounds like what Bio::Root::Root does is  
what you want, but you want a little more information when exceptions  
are thrown maybe?

from perldoc Bio::Root::Root:

...
          # Alternatively, using the new typed exception syntax in  
the throw() call:

            $obj->throw( -class => 'Bio::Root::BadParameter',
                         -text  => "Can not open file $file",
                         -value  => $file);
...

        Typed Exception Syntax

        The typed exception syntax of throw() has the advantage of  
plainly
        indicating the nature of the trouble, since the name of the  
class is
        included in the title of the exception output.

        To take advantage of this capability, you must specify  
arguments as
        named parameters in the throw() call. Here are the parameters:

        -class
            name of the class of the exception.  This should be one  
of the
            classes defined in Bio::Root::Exception, or a custom  
error of yours
            that extends one of the exceptions defined in  
Bio::Root::Exception.

        -text
            a sensible message for the exception

        -value
            the value causing the exception or $!, if appropriate.

        Note that Bio::Root::Exception does not need to be imported  
into your
        module (or script) namespace in order to throw exceptions via
        Bio::Root::Root::throw(), since Bio::Root::Root imports it.


Chris

On Jul 11, 2006, at 3:58 AM, Rutger Vos wrote:

> Dear all,
>
> would it be possible to overload Bio::Root::RootI's 'throw' method to
> accept an additional, optional (positional) argument to define the
> exception class, e.g. using Exception::Class:
>
> # ...somewhere ...
>
> sub makefh {
>     my ( $self, $filename ) = @_;
>     open my $fh, '<' $filename or $self->throw("Can't open file: $!",
> 'Bio::Exceptions::FileIO'); # NOTE second argument
>     return $fh;
> }
>
> #.... somewhere else
> my $fh;
> eval {
>     $fh = $obj->makefh( 'data.txt');
> }
> if ( $@ and $@->isa('Bio::Exceptions::FileIO') ) {
>     # something's wrong with the file?
> }
>
> -- 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> Rutger Vos, PhD. candidate
> Department of Biological Sciences
> Simon Fraser University
> 8888 University Drive
> Burnaby, BC, V5A1S6
> Phone: 604-291-5625
> Fax: 604-291-3496
> Personal site: http://www.sfu.ca/~rvosa
> FAB* lab: http://www.sfu.ca/~fabstar
> Bio::Phylo: http://search.cpan.org/~rvosa/Bio-Phylo/
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>
>
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Christopher Fields
Postdoctoral Researcher
Lab of Dr. Robert Switzer
Dept of Biochemistry
University of Illinois Urbana-Champaign