Sebastian Hammer wrote:
> Jakob Voss wrote:
>> Rob Sanderson wrote:
>> I still wonder how people can call something a standard that is not
>> publically available.
> Many, many people have asked themselves the same question..
I bought the d*mn thing. Can you belive it?
>> CCL is very poorly documented - you can use it in many OPACs in some
>> way but libraries seem to hide it from the user. If you send me a PDF
>> of ISO 8777 I can try to summarize the differences and commonalities
>> with CQL.
> Unfortuantely, ISO8777 doesn't even describe the language that lucidly
> -- the stnadard predates context-free grammars (at least I hope it does
> -- otherwise, I don't know what their excuse would be). Adam put quite a
> bit of effort into capturing the essence of the language in a BNF
> notation.. that might actually be the easiest place to start. You'll
> find it at http://www.indexdata.dk/yaz/doc/tools.tkl#CCL
Yes, the CCL 1993 version is the most recent version, AFAIK. It does not
include a grammar. But it outlines some kind of priority. It also
includes description of the lexical convensions. All reserved words must
be quoted, such as "and" if to be used as a search term. IIRC, the
ISO8777 is based on the even older DS (danish standard) CCL.
One thing that is unclear in the CCL spec is that there appears examples
where the relation is omitted, e.g.
TI,SU tom sawyer
OTOH, the spec says that
"Qualifiers shall precede the a search term and shall be connected to
the search term by an = , or where appropriate, by a ranging operator"
YAZ' CCL parser always require a relation operator. If it didn't, all
qualifiers would have been reservered words too.
When reading the CCL spec you really miss the usage of proper wordings,
MAY, MUST etc.. So we should aim for that - whoever suggested that.
> All the best,