[Versa] More on literal queries

[Uche Ogbuji]

On Tue, 2005-09-06 at 08:50 -0600, Michael Olson wrote:
> On Sep 6, 2005, at 7:19 AM, Chimezie Ogbuji wrote:
> This is a good solution for me.

Whew!

OK, onward with the good ship.

> Here is what I see ignoring the issue  
> of scopes and only highlighting what the changes.


> query-expression :== filter | traverse | funtion-call
> 
> forward-filter :== set-expression '-' set-expression '->'  
> filter-expression
> #plus all of the rest of the filters and traverses
> 
> 
> set-expression :== query-expression | pattern | context |  
> variable-reference
> 
> filter-expression :== query-expression | pattern | operator-expression  
> | context | variable-reference
> 
> pattern :== uri-pattern | literal-pattern | wild-card
> 
> function-call :== qname '(' argument-expression ? ( ','  
> argument-expression) * ')'
> 
> argument-expression :== query-expression | constant |  
> variable-reference - context | '{' argument-expression '}'
> 
> context :== '.'
> 
> wild-card :== '*'
> 
> constant :== uri-constant | literal-constant | string-constant |  
> number-constant | boolean-constant

Looks about right, but I do wonder whether the recent discussion over
scope affects some of this as well.


> What this allows then is we would not need to wrap all of our  
> filter-expressions in "eq" if we don't want because
> 
> all() - rdf:value -> "foo"
> 
> would become a valid query as "foo" becomes a literal-pattern.

I think this leads back to an earlier discussion we were having about
patterns versus predicates.  I'll need to go back and read as a
refresher (it was from the initial burst of Versa NG discussion).


-- 
Uche Ogbuji                               Fourthought, Inc.
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