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What is the semantics of del_attr('font') on a start tag when the attr is missing? Does it croak or "fail" silently?
I.e. does del_attr() guarantee that an attr will be deleted (i.e. the tag modified), or does it guarantee that the attr 'font' will not be in the tag after being run?
If the semantics is focused on the deletion, it's not appropriate to modify a closing tag if a closing tag can't be modified (by removing attributes).
If the semantics is focused on the absence of the attribute after running the method, it's appropriate to leave it to the object to know that "hey, there can't be any attributes here anyway, so I'll let it slide".
Personally, I'd go with the second alternative, since it lays down fewer rules about how to use the class (this method must only be called in this state!) while (meththinks) providing the same functionality.
From the user's perspective, the important thing is probably that the attribute is gone, not that it was deleted.
Now, I don't know anything about HTML::TokeParser::Simple, but is it really impossible for closing tags to have attributes? If passed invalid HTML? If so, is it the responsibility of the class to do anything about it?
In reply to Re: OO style question: how much information to hide?