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Re: Defaulting pipeline inputs and outputs

From: Norman Walsh <ndw@nwalsh.com>
Date: Thu, 09 Aug 2007 16:49:05 -0400
To: public-xml-processing-model-wg@w3.org
Message-ID: <87lkckfn7i.fsf@nwalsh.com>
/ "Innovimax SARL" <innovimax@gmail.com> was heard to say:
| Let's give some troubling example
| <p:pipeline>
|   <p:xslt/>
| </p:pipeline>
| what is supposed this one to be equivalent to ?
| How many implicit inputs are generated ?

We've already answered these questions. That pipeline isn't valid.
Only the primary input port (or primary output port) is ever
implicitly created.

In the case of an input port, it's created so that it can be
implicitly connected to the primary input port of the first step if
and only if the first step has one.

In the case of an output port, it's created so that it can be
implicitly connected to the primary output port of the last step if
and only if the last step has one.

The p:xslt step has a second (non-primary) input. That input *has* to
be explicitly bound. Non-primary inputs are never implicitly bound,
either to implicitly created pipeline inputs or to the primary output
of preceding steps.

| Now that we have parameter ports it seems more and more unlikely to be
| fully manageable by users (may I recall than nothing forbid an input
| of kind="document" to be connected to an input of kind="parameter"

The vast majority of users are just going to ignore parameter inputs.
They're going to just work.

| And what about :
| <p:pipeline>
|   <p:xslt/>
|   <p:split-sequence test="position() mod 2 = 1"/>
| </p:pipeline>
| I think that such shortcut seem very appealing but are going to make
| verification very tortuous

I don't see that, at least not yet. The rules seem pretty
straightforward to me and the pipeline that you get from "expanding"
the syntactic shortcuts is completely deterministic.

(I'm not saying your wrong, I'm just saying, I don't see it.)

                                        Be seeing you,

Norman Walsh <ndw@nwalsh.com> | Few men are so sufficiently discerning
http://nwalsh.com/            | to appreciate all the evil that they
                              | do.--La Rochefoucauld

Received on Thursday, 9 August 2007 20:49:19 UTC

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