[css] css3-selectors to XPath

[Bjoern H. <der...@gm...>]

Hi,

  The attached file is an extension for CSS::SAC to convert selectors to
XPath predicates. For example,

  span[title="a"]

would be converted to

  local-name() = 'span' and @*[local-name() = 'title'
    and namespace-uri() = ''][. = 'a']

The XPath expression is not meant to be readable, e.g. in order to help
people to map one syntax to another but rather to implement
css3-selectors on top of an XPath implementations. It implements all
structural selectors but :nth-last-... pseudo-classes as they are broken
by CSS::SAC (see my earlier bug report). It has some limitations:

  * classes are considered equivalent to [class~=...]
  * no support for *:...-of-type, e.g. :nth-of-type(2n+1) as I think
    there is no equivalent for this functionality in XPath
  * ' is not allowed within arguments as the character is used to
    delimit strings
  * there might be issues with the an+b syntax,
    e.g., :nth-child(n-2) is considered invalid

There is a workaround for the :not argument bug reported earlier, it
assumes that the CSS::SAC namespace bugs are fixed (as currently in
CVS). The code requires the GetElement extension (see previous message).

Could we maintain this in CVS? Where?

regards.