[Templates] How To Throw Exception on Missing Method

[Paul Seamons]

> Here is some quick untested pseudo code.

And here it is on Template::Alloy:

use Template::Alloy;
use Scalar::Util qw(blessed);

my $tt = Template::Alloy->new(UNDEFINED_ANY => sub {
    my ($self, $ident) = @_;
    return '' if ! ref $ident;
    my ($obj, $args, $dot, $meth) = @$ident;
    return '' if ! blessed($obj) || $obj->can($meth);

    $self->throw('invalid_method', "Bad method $meth on class ".ref($obj));
});