Thank you Richard and Antoine. I think I see the pointlessness of my ask.
Regards, Kashyap On Mon, Jul 30, 2012 at 4:14 AM, Richard O'Keefe <o...@cs.otago.ac.nz> wrote: > > On 29/07/2012, at 6:21 PM, C K Kashyap wrote: > > I am struggling with an idea though - How can I capture the parent > element of each element as I parse? Is it possible or would I have to do a > second pass to do the fixup? > > Why do you *want* the parent element of each element? > One of the insanely horrible aspects of the Document Object Model is that > every > element is nailed in place by pointers everywhere, with the result that you > cannot share elements, and even moving an element was painful. > I still do a fair bit of SGML/XML process in C using a "Document Value > Model" > library that uses hash consing, and it's so much easier it isn't funny. > > While you are traversing a document tree it is useful to keep track of the > path from the root. Given > > data XML > = Element String [(String,String)] [XML] > | Text String > > you do something like > > traverse :: ([XML] -> [a] -> a) -> ([XML] -> String -> a) -> XML -> a > traverse f g xml = loop [] xml > where loop ancs (Text s) = g ancs s > loop ancs e@(Element _ _ ks) = f ancs' (map (loop ancs') ks) > where ancs' = e:ancs > > (This is yet another area where Haskell's non-strictness pays off.) > If you do that, then you have the parent information available without > it being stored in the tree. > > > > >
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