Interesting point from this morning

[resending w. correct address for John, please reply to this one]

I understood someone (who?) to say something along the lines of:  "I'd
like an API I could use to get a pipeline built".

That happens to fit pretty well with the way I've been trying to address
the 'abstract semantics' problem.  And at lunch today, where I ended up
with Mohamed, Romain, Florent and John Snelson, we had a useful
discussion about possible language architectures, i.e. how many
languages do we have, and what's their relationship.

We came up with at least the following possibilities:

 1) The XML syntax defines the language, there is a read-only textual
    version;

 2) The XML syntax defines the language, there is an executable textual
    syntax, but it's not normative nor is support required for
    conformance (this was asserted to be the RNG/RNC story);

 3) The compact syntax is normative, it maps to an XML language which
    defines the semantics but is not optimised for human-readability
    (this could be sort of Vnext as we had been working towards it,
    perhaps w/o (much) defaulting);

 4) The compact syntax is normative, it maps to a set of logical
    assertions/object creation calls which defines the semantics, and
    which in turn has an XML syntax (what I think I heard from the
    floor).

Wrt the very preliminary way I've been going about this, here's what (4)
would look like for a trivial example:

s1 == StepImpl(p:load,uri="somedoc.xml")
s2 == StepImpl(p:data,type="application/xml",data="<d colour="pink">")
s3 == StepImpl(p:set-attributes,match="//*[@colour='red']")
s4 == StepImpl(p:serialize)
p1 == Pipe(s1.result,s3.source)
p2 == Pipe(s2.result,s3.attributes) 
p3 == Pipe(s3.result,s4.source)

The XML for this is left as an exercise for the reader.

ht
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, 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/
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Received on Thursday, 11 February 2016 15:05:56 UTC