response to issue pfps-07

The rules for typed literals are incomplete.  They do not give a
meaning for "a"@t^^dt:foo, for dt:foo a datatype and t a language tag.

-----
True, and this was a pure editorial slip-up on my part, which others 
also noted. This will be fixed.

The proposed form of the datatype semantic conditions are now:
1.
For any typed literal "sss"[@ttt]^^ddd in G, if I(ddd) is in D and 
'sss' is a valid lexical form for I(ddd) then IL("sss"[@ttt]^^ddd) = 
L2V(I(ddd))(sss)
2.
For any typed literal "sss"[@ttt]^^ddd in G, if I(ddd) is in D and 
'sss' is not a valid lexical form for I(ddd) then 
IL("sss"[@ttt]^^ddd) is not in LV

where the [square brackets] indicate that this part of the literal 
syntax is optional.

There is a corresponding (new) inference rule described by the 
following proposed text added to section 4.3:

------
Since language tags play no role in the meaning of a typed literal, 
they can in practice be ignored, and any literal of the form 
"sss"@ttt^^ddd, where ddd is not rdf:XMLLiteral, treated as identical 
to the same literal without the language tag, "sss"@ddd. We can 
capture this convention by special rules which allow language tags to 
be inserted or removed:

rdfD 0a

aaa ppp "sss"@ttt^^ddd .
=>
aaa ppp "sss"^^ddd .

rdfD 0b

aaa ppp "sss"^^ddd .
=>
aaa ppp "sss"@uuu^^ddd .

Here, ttt and uuu are any legal language tags and ddd is anything 
other than 'rdf:XMLLiteral'. Clearly, these rules together can 
replace any language tag by any other.

---

BTW, for XML literals the conditions (on RDF-interpretations) are:

if sss is a unicode string which can be parsed into a well-formed XML 
document, then

IL("sss"^^rdf:XMLLiteral) is the XML canonical form of the XML 
document obtained by parsing sss as XML

and if ttt is a language identifier then

IL("sss"@ttt^^rdf:XMLLiteral) is the XML canonical form of the XML document
<rdf lang="ttt">sss</rdf>

and otherwise IL("sss"[@ttt]^^rdf:XMLLiteral) is not in LV
---

Pat



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