Re: Saxonica Comments on XProc last-call draft, sections 1 and 2

/ Michael Kay <mike@saxonica.com> was heard to say:
|> For V1, the WG has decided that all parameters will be 
|> exclusively strings.
|
| Sounds to me like a simplification too far. Makes it quite hard to write a
| pipeline in which a transform step merges two input documents that are
| constructed by earlier stages.

Yes, I was personally quite surprised when consensus went that way, but
it did. I don't think it's really a very significant limitation because
XProc steps give you other ways of tackling the problem. The first
that occurs to me is:

  <p:wrap-sequence>
    <p:input port="source">
       <p:pipe ... gets the first of two documents ... /> 
       <p:pipe ... gets the second of two documents ... /> 
    </p:input>
    <p:option name="wrapper" value="wrapper"/>
  </p:wrap-sequence>

Send the output of that step on to your transformation and
grab the two documents from inside the "wrapper".

I'm sure that there are some things that could be done more
conveniently with structured parameter and option values, but I think
you'll need some pretty compelling use cases to persuade the WG to
undertake that large a change.

|> | 11. Technical 2.8.1. Making the default context node an "empty 
|> | document node" is probably a mistake; you would want to make the 
|> | decision differently with XPath 2.0, and it will be hard to 
|> change later.
|> 
|> What do you suggest?
|
| Well, firstly, I think you should allow XPath 1.0 or 2.0 at implementor
| discretion (with the user perhaps declaring what they are using). Then say
| that it's an error to refer to the context node if there isn't one, but an
| XPath 1.0 processor may use the fallback of returning an empty document.

We considered allowing either. We were dissuaded by interoperability
concerns. On the other hand, when we started it seemed possible that
we'd finish before XPath 2.0 :-).

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | Irrigation of the land with seawater
http://nwalsh.com/            | desalinated by fusion power is ancient.
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