Re: PSVI issues

Henri,

Can you give one or two use cases for psvi-available() ?

Mohamed

On Thu, May 8, 2008 at 3:11 PM, Henry S. Thompson <ht@inf.ed.ac.uk> wrote:

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> 1) The functionality provided by the 'psvi-required' attribute is
>   perfectly reasonable and self-contained, and it should be retained
>   unchanged.  If I want to write pipelines which simple won't work
>   (statically) when a processor doesn't support the PSVI, that's what
>   I'll use.
>
> 2) I am unconvinced that we need to provide a means to tell processors
>   which do support the PSVI whether or not they need to do so when
>   executing a particular pipeline.  That feels like an
>   product-specific optimisation to me, and as such _finally_ gives me
>   an example of a realistic use for <pipeinfo> -- a product is free
>   do define a <pipeinfo> child which can be inserted before
>   e.g. validate steps to say, in effect, "I do/don't care about the
>   PSVI".
>
>   I'd rather wait until we see if such annotations turn out to be
>   provided, and what they look like, before trying to add something
>   along those lines into the language.
>
> 3) Having said that, I think it _does_ make sense to provide a means
>   for pipeline authors to do something at runtime depending on PSVI
>   support.  But I think the minimum necessary to declare victory is
>   just psvi-available(), which if true means the processor claims
>   it's passing PSVI information along.  No granularity or locality is
>   implied, that is, the value should be the same at all times/places
>   within a given episode.
>
> 4) Wrt to the amount of support required, I think we say PSVI support
>   implies two things:
>
>   a) All PSVI properties produced on the output of a step MUST be
>      available to the steps which take that output as one of their
>      inputs;
>
>   b) Implementations SHOULD preserve PSVI properties across steps
>      insofar as that is consistent with step semantics.  It is
>      implementation-defined what PSVI properties it supports overall,
>      and what PSVI properties are lost by what steps.
>
> 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/<http://www.ltg.ed.ac.uk/%7Eht/>
> [mail really from me _always_ has this .sig -- mail without it is forged
> spam]
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