On Thu, May 23, 2002 at 07:41:12PM -0400, Ray denenberg wrote:
> > CqlString ::= OrTerm *( "OR" OrTerm )
> > OrTerm ::= AndTerm *( "AND" AndTerm )
> > AndTerm ::= Term *( "NOT" Term )
> > Term ::= QualifiedTerm | "(" CqlString ")"
>
> This raises (again) the question, are we defining a wire- or
> human-readable/typeable-syntax, and of course, the answer is something in
> between.
Hmmm. Not quite human, not quite computer format. I know!
How about programmer friendly!!! :-) :-) :-)
More seriously, I was not sure how your comment related to the grammar.
In both cases, boolean operator priority is important to specify.
Writing it into the grammar I thought was a generally accepted way
to make it explicit and avoid ambiguity (the old grammar did not
address operator priority, and so was either ambiguous, or had
left-to-right semantics always (which is uncommon).
I actually think being programmer intuitive is important for SRW/SRU.
Being end-human friendly is benefical. But to express complex concepts
in a query, you are going to have to be trained. So being logical
and consistent is a good goal.
> But with this definition, will the productions be intuitive enough?
I am not sure - are you mixing how the grammar is written with semantics
of what the grammar expresses? The above sort of grammar of having
rules per operator is the standard approach for specifying operator
priorities unambiguously in grammars. Its what any programmer who
had to implement CQL would be looking for (well, in my opinion anyway -
I majored in compiler writing back in my Uni days).
> > * I will raise (not propose) that CCL allows multiple IndexQualifiers
> > in front of a single term (so you can say Author,Title="smith").
>
> Is this just to avoid constructing an OR? or does this refer to an
> Author/title index?(In which case, just define an Author/title index.)
It was an OR, which is why I raised it but not proposing it. It was a
CCL shorthand. CQL is formally complete without it.
Alan
