RE: [Xmlstar-devel] Great!

[<mgr...@co...>]

Here is what was my original thinking on using XPATH expressions in r-values 
for edit.

Right now to update attribute value you would do something like

xml ed -u //@id -v 2

//@id    - points to a node being updated
2        - specifies value (constant)


Here is how I would envision incremental update

xml ed -u //@id -x "@id+1"

//@id    - points to a node/nodes being updated
           and gives a context for xpath expressions

@id+1    - specifies xpath expression within the context
           defined in -u option. This expression evaluates
           and its value is assigned to a node selected
           in -u.

Something like that...

--Mikhail



> I did not put much thought yet but here is an idea...
> 
> With the xml ed, we are actually replacing something with something else. So
> the basic idea is xml ed -u "..." -x "..." where -u is the r-left and -x is
> the r-right values.
> 
> However, it is often difficult to construct an XPath for the r-value in one
> statement. I was rather thinking something in the line of :
> 
> xml ed -u "..." -r ...multiple statements...
> 
> In multiple statements we must be able to match (-m), copy (-c), add a tag
> (-e), get a value (-v), evaluate an XPath (-x), delete a tag (-d) and maybe
> more. Each of these actions are "piped" together as usual, and the result of
> the last command will be pasted in the l-value. I dont know what can happen
> if you try to replace an attribute with an XML node instead of a value?
> 
> Therefore we could do something like:
> 
> xml ed -u "..." -r -m "/Record/Number" -v "node()" -x "some XPath that adds
> 1 to the -v" ...
> 
> This example is obvisouly overkill for what it does.
> 
> Daniel Shane
> 
>