Re: Help with xml & lua

[Hans Hagen <pragma@wxs.nl>]

On 8/2/2017 5:23 PM, Olivier Binda wrote:
> Hello
> 
> I have been trying for the past 3 days to process files with xml on the 
> lua side (with Context beta 0.70), but I'm at then end of my wits and 
> really need help.
> 
> On the lua side, I would really like to be able to :
> 
>   1) transform a tree : replace nodes with other nodes
> 
>   2) transform a tree : walk it and modify node attributes
> 
>   3) walk a modified tree and flush it with setups

what do you mean with 'walk with setups' ... at the lua end? setuips are 
something at the tex end

> Could someone give me hints or better yet a lua snipet that :
> 1) load a tree in lua
> 2) modify it
> 3) walk it
> 4) it can be done again

in some cases you need to apply setups after adaption, eg with

\xmlregistereddocumentsetups{...}{...}

> I have had some success with 1, but lost 2 days trying to make 2 & 3 
> work with setups
> 
> A) I managed to replace a node of an xml document with a subtree of 
> another xml document by doing :
> 
> -- load the main tree
>    local mainTree = lxml.load("mainTree", "mainFile.xml)
> 
>    local replacementNode = xml.first(lxml.load("replacement", 
> "replacementFile.xml), somePattern)
> 
> -- replace nodes
>    for node in xml.collected(tree, pattern) do
>          node.tg ="toBeReplaced"
>          xml.replace(tree, "toBeReplaced", replacementNode)
>    end
> 
> But then I failed to walk the modified tree with setups : my setups for 
> "mainTree" work, but not for the inserted subtrees

at the lua end there's lxm.include

(there's also some some indexing going on)

> B) So, to process my tree further, I need to first serialize it
> 
> -- save the modified tree
> 
>   xml.save(mainTree, "saved.xml")
> 
> And then, I can reload the modified tree and work further with it (but 
> it sucks to have to save to reload).

\xmlinclude should work ok (at least it does at our end) given that you 
do it before associating the setups

> C) "xml.replace" works in a weird way : it erases node (toBereplaced) 
> and inserts the children of replacementNode as children of the parent of 
> the node to be replaced...
> 
> D) I did not manage to walk a tree loaded with xml.load in lua. I know 
> that I have to register setups, I tried all sort of things, looked at 
> the Tex/Lua context source code but could not make it work. Also the xml 
> documentation for context on the net is really old, sparse and obsolete.
> 
> On the tex side, it works : \xmlprocessfile{mySetups}{saved.xml}{} works 
> like a charm
> But the TeX commands don't allow you to grab a modified xml tree, once 
> you have walked it
> 
> E) I tried
> 
> lxml.load(id, filename)
> context("\\xmlregistereddocumentsetups{" .. id .. "}{}")
you need to provide (small) working (valid) examples

Hans

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                                           Hans Hagen | PRAGMA ADE
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