Glimpsing through the source, it doesn't look as if it'd be too hard to patch it so that ignore_unknown could be a coderef instead of a boolean value. Then you could set it to a predicate which looks at the tag name and returns whether or not to ignore it. 

## ... circa line 152 of HTML/TreeBuilder.pm
$self->{'_ignore_unknown'}    = sub { 1 };


## ... circa line 660 in HTML/TreeBuilder.pm
if( $self->{ '_ignore_unknown' }->( $tag ) ) {
  print $indent, " * Ignoring unknown tag \U$tag\E\n" if DEBUG
  $self->warning("Skipping unknown tag $tag");
  return
}

## ... later in your code
$tree->ignore_unknown( sub { return 1 if $_[0] !~ /^mig:/ } );

[download]

As is you'd have to make your own copy and/or edit the installed version instead of overriding in a subclass. But still, easily do-able (and if you get it working right submit a patch :).

In reply to Re^3: Custom XML tags in HTML::TreeBuilder and HTML::Element by Fletch
in thread Custom XML tags in HTML::TreeBuilder and HTML::Element by slaniel

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