But parenthesis aren't mandatory. So for example:
"A or B and C" is good, and would evaluate to "(A or B) and C"
(left-to-right) and if you wanted instead "A or (B and C)" then you would
need to explicitly include the parenthesis in the string.
So Rob, are you saying that anytime you have a prefix assignment,
parenthesis become mandatory, at least for the search clause that the
----- Original Message -----
From: "Robert Sanderson" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 09, 2003 12:59 PM
Subject: Re: let's try another mailer......
> > > Allow me to repeat the grammar in used by parsers and semantics for
> > it:
> > > search-clause ::= ">" [identifier "="] term cql-query
> > Does this produce unambiguous cql?
> > >dc1="core-v1" dc1.title=first and dc1.title=second
> > Is the second dc1 governed by the first assignment? If so, is that
> > because the first assignment is "global" (and if so how do we know that)
> > or because it is the most recent assignment for dc1?
> Yes and no, respectively, as I understand it:
> It does apply to both because the bracketing is implicitly:
> > dc1="core1" (dc1.title = first and dc1.title=second)
> So if you have multiple prefixes:
> >dc1=foo ( >dc2=foo2 ( >dc3=foo3 ( cql.resultsetname="fish" )))
> > How about:
> > >dc1="core-v1" dc1.title=first and >dc1="core-v1a" dc1.title=second
> > and dc1.title=third
> Lets remove the mappings and put in the parens:
> ((dc1.title=first and dc1.title=second) and dc1.title=third)
> And put back the mappings:
> >dc1=v1 ((dc1.title=first and >dc1=v1a dc1.title=second) and
> > The third occurence of dc1 -- is it governed by the first or second
> > assignment?
> First, due to the left to right ordering of parens.
> ,'/:. Dr Robert Sanderson ([log in to unmask])
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