Date:         Mon, 1 Dec 2003 11:20:34 +0000
Reply-To:     "Z39.50 Next-Generation Initiative" <[log in to unmask]>
Sender:       "Z39.50 Next-Generation Initiative" <[log in to unmask]>
From:         Robert Sanderson <[log in to unmask]>
Subject:      Re: New proposed grammar for CQL (revised from Yacc grammar)
Comments: To: "Z39.50 Next-Generation Initiative" <[log in to unmask]>
Comments: cc: [log in to unmask]
In-Reply-To:  <[log in to unmask]>
Content-Type: TEXT/PLAIN; charset=US-ASCII

> >>If people want 1.1 finished soon, I raise the option of leaving out
> >>indexes on parenthesis groups for post 1.1 to allow people to think
> >Yes please.

> What are people afraid of? Is it difficult to implement? Difficult to
> understand? Difficult to describe?

Yes to all of the above.

dc.title = ( dc.author = fish )

I see no reason to make that legal as dc.title is just a waste of time,
making the query less readable for no gain.

dc.title = (fish or cat)

I see no reason to make that legal either, as we can do:
    dc.title any "fish cat"
and have the same result for no gain.

dc.title = (dc.author any fish or cat)

Is just ugly.  Is cat searched in author or title?  Yes, I'm sure there's
a right answer but to me (who's fairly technical) that answer is not
readily apparent.  To my partner (who's not technical at all, but
understood Mike's CQL tutorial in one reading) it would be totally opaque.
No gain.

It's harder to implement ...

(you need to constantly check the type of 'term' when processing and
resolve clauses/booleans/strings, rather than knowing they'll be strings.
*[1])

... harder to understand ...

(try describing dc.title = dc.author = fish to someone who's not
technically inclined, rather than dc.author = fish and seeing which they
grasp)

... and harder to describe ...

(The semantics are understandable, but the idea is to have a useful but
understandable to novices language.  Describing how to resolve which
index is in effect is more difficult).

The proposal in my view doesn't gain us anything and loses both
readability and understandability.

I don't mind if Indexdata's parsers implement it, but I am not going to
try and describe why such queries should be legal to end users of CQL, who
are supposed to be not technical people.

Rob

1:

And then we need to decide the scope of term describing relation modifiers:

 dc.date any/iso.YYYYMMDD ( dc.author =/cql.string "fish" and "20030224" )
 geo.location within/geo.box/geo.pointFormat  ( ... )

Please No!

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