W3C home > Mailing lists > Public > public-xml-processing-model-wg@w3.org > June 2007

Re: On parameters

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Thu, 14 Jun 2007 12:08:13 +0100
To: Norman Walsh <ndw@nwalsh.com>
Cc: public-xml-processing-model-wg@w3.org
Message-ID: <f5blkemvlnm.fsf@hildegard.inf.ed.ac.uk>

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I can certainly live with this, and I agree that the basic analysis is
correct, but I have a few residual concerns:

1) We are grabbing another port name for pipeline use;
2) I'm not sure about the whole defaulting situation. . .

Let's look at the latter a bit.  At least one possible story would be:

 a) If a step-type is not declared to take a 'parameters' input, then
    an instance of that step only sees parameters explicitly specified
    with <p:parameter> directly within that instance;

 b) If a step-type is declared to take a 'parameters' input, and a
    binding for that port is given on an instance of that step, then
    that instance sees all and only the parameters presented on that
    port and the parameters explicitly specified with <p:parameter>
    directly within that instance (and the latter take precedence);

 c) If a step-type is declared to take a 'parameters' input, and no
    binding for that port is given on an instance of that step, then
    that instance sees all and only the #pipeline-parameters and the
    parameters explicitly specified with <p:parameter> directly within
    that instance (and the latter take precedence).

So you can 'protect' a step _type_, by not declaring a 'parameters'
input for it, but if a step type _is_ declared to have a 'parameters'
input port, then you have to do

  <p:input port="parameters">
   <p:empty/>
  </p:input>

to 'protect' an _instance_ of such a step type.  I guess I think
that's about right.

ht
- -- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
    2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
            Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
                   URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.6 (GNU/Linux)

iD8DBQFGcSGdkjnJixAXWBoRAl6QAJ95gPtwEW4zsQnBpAQsxMy0Lqa+IACfbuUt
fswQuqJb9E72XZCBFa6ZBfQ=
=a1lC
-----END PGP SIGNATURE-----
Received on Thursday, 14 June 2007 11:08:22 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 8 January 2008 14:21:53 GMT