From: Robert Klemme <shortcutter@...>
Date: 2006-07-08T19:50:05+09:00
Subject: Re: libhxml Node#remove! kills each loop and extension to #<<

2006/7/8, transfire@gmail.com <transfire@gmail.com>:
> hi,
>
> While using #each to loop thru the children of a Node, if I remove a
> node the loop breaks on it's own.
>
>   <root>
>     <a id="a"></a>
>     <b id="b"></b>
>     <c id="c"></c>
>   </root>
>
>   root.each { |node|
>     if XML::Node === node
>       node.content = "yep"
>       node.remove! if node['id'] = "b"
>     end
>   }
>
> The result is
>
>   <root>
>     <a id="a">yep</a>
>     <c id="c"></c>
>   </root>
>
> Would tha tbe a bug? Or something that simply can't be avoided?

It's usually a problem to change a container while iterating through
it. This can generate all sorts of weird effects. It's generally
better to rely on this *not* being possible unless explicitely stated
(e.g most of Java's iterators implement remove() which savely removes
an element while iterating).

In your case I'd either first remove the one you want to get rid of,
iterate using an index (if that's possible) or remember objects to
remove in some kind of container and do the removal after the
iteration (probably the most efficient solution).

Kind regards

robert

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