p:input doppelgangers (was Re: Publication Request: XProc on 6 July 2007)

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

So on further reflection, here's how I think it ought to be, and why:

 p:viewport-source
   (p:pipe | p:document | p:inline )?

   That is, no change, because p:viewport is like a step with a single
   required input.

 p:iteration-source
   (p:empty | (p:pipe | p:document | p:inline )+ )?

   That is, exactly as p:input, because p:for-each is like a step with
   sequence in and out, and should be allowed to be forced to iterate
   no times and produce an empty sequence.

 p:xpath-context
   (p:empty | p:pipe | p:document | p:inline )?

   A special case -- exactly one document, or none.  A dynamic error
   if p:empty is used and a 'test' XPath expression appeals to the
   context-node or context-position.

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)

iD8DBQFGi7rokjnJixAXWBoRAliwAJ0b8x9Tr+iGmh5SIB2YE8PKfUdTRACfYGyN
NLjyMKeOJ4fu9iZyfFd9Ttg=
=K2/L
-----END PGP SIGNATURE-----

Received on Wednesday, 4 July 2007 15:21:36 UTC