+++ /dev/null
-From mike@seatbooker.net Tue Oct 29 15:12:09 2002
-Envelope-to: mike@miketaylor.org.uk
-Date: Tue, 29 Oct 2002 14:11:48 GMT
-From: Mike Taylor <mike@seatbooker.net>
-To: ZNG@loc.gov
-Cc: mike@miketaylor.org.uk
-Subject: Again: Grammar Tweaks
-
-Dear Everyone,
-
-I sent this message last Friday, and didn't get a delivery failure
-message or anything similar; but there has been absolutely zero
-response on-list, which makes me wonder whether it mysteriously didn't
-get through.
-
-... or surely it didn't get caught by people's "this message is too
-complicated to pay attention to" filters? :-~
-
- _/|_ _______________________________________________________________
-/o ) \/ Mike Taylor <mike@miketaylor.org.uk> www.miketaylor.org.uk
-)_v__/\ "Conclusion: is left to the reader (see Table 2).
- Acknowledgements: I wrote this paper for money" --
- A. A. Chastel, _A critical analysis of the explanation of
- red-shifts by a new field_, A&A 53, 67 (1976)
-
-
-------------------------------- cut here -------------------------------
-Well, it looks like the CQL grammar has settled down more or less to
-everyone's satisfaction. So it must be time to throw it all up the
-air again! :-)
-
-No, I'm joking -- mostly. I'd like to point one actual mistake (I
-think), suggest one substantive change, and request a few cosmetic
-changes.
-
-For anyone who's not got it to hand, the URL for the grammar is
-http://lcweb.loc.gov/z3950/agency/zing/srwu/cql.html
-
-1. I think it's a mistake that the grammar says:
- prox-qualifiers ::= "/" [ unit ] "/" [ relation ] "/" [ distance ] "/" ordering
- (and the similar productions that follow) because that allows
- prox/word/exact/3 <--- "exact" is meaningless here
- and -- even worse --
- prox/word/=/stem <--- a relation-modifier!
- (This is not only silly, but ambiguous too)
-
- So I think all the occurrences of "relation" in the productions
- for prox need to be changed to "order-or-equal-relation".
-
-2. The only thing that I'm suggesting we actually _change_ is the
- order of the proximity parameters. Quick! Close your eyes and
- tell me the correct order of relation, ordering, distance and
- unit? See -- you can't do it: no-one can :-)
-
- So, based somewhat on Adam's rather more difficult suggestion of
- a couple of days ago, I propose that we change the order to:
- relation/distance/unit/ordering
- Rationale: you can read it out loud. If you want to find two
- clauses with the conditions "*more* than *5* *sentences* apart",
- you would write ``foo prox/>/5/sentence bar''.
-
-3. Cosmetic changes.
-
- 3a. The "/" at the beginning of each of the prox-qualfiers
- productions can be moved up into the definition of prox, like
- this:
- prox::= "prox" [ "/" prox-qualifiers ]
- which yields a slightly simpler, neater (but equivalent)
- grammar.
-
- 3b. The things that the grammar called "index-name", we have been
- calling "qualifiers" (and talking about the "qualifier-sets"
- that contain them.) I think that's a much nicer name than
- "index-name", in part because it doesn't carry such a loading
- of implementation detail. Also, remember that we way we've
- designed things, a qualifier will typically implemented by
- multiple indexes (a word index and a string index) so I don't
- want to give misleading impressions.
-
- 3b1. :-)
- That would mean that, in the name of simplicity, we'd
- need to rename "prox-qualifiers" to something like
- "prox-modifiers" or "prox-parameters" (which is what
- we've actually been calling them, 4WIW) and rename
- "qualifier" to something more suggestive such as
- "relation-modifier" (which, again, is what we've been
- using in prose.)
-
- 3c. (Nearly done, honest.) I think that
- "order-or-equal-relation" is a horrible name and would much
- prefer to call it something like "numeric-relation", which
- better explains its role in, for example, proximity
- parameters.
-
-So, putting it all together, here's how I think the grammar should
-look:
-
-------------------------------- cut here -------------------------------
-cql-query ::= cql-query boolean search-clause
- | search-clause
-boolean ::= "and" | "or" | "not" | prox
-search-clause ::= "(" cql-query ")"
- | [ qualifier relation ] term
-
-relation ::= base-relation { "/" relation-modifier }
-base-relation ::= numeric-relation | "exact" | "all" | "any"
-relation-modifier ::= "relevant" | "fuzzy" | "stem"
-numeric-relation ::= "<" | ">" | "<=" | ">=" | "<>" | "="
-
-prox ::= "prox" [ "/" prox-parameters ]
-prox-parameters ::= [ numeric-relation ] "/" [ distance ] "/" [ unit ] "/" ordering
- | [ numeric-relation ] "/" [ distance ] "/" unit
- | [ numeric-relation ] "/" distance
- | numeric-relation
-unit ::= "word" | "sentence" | "paragraph" | "element"
-ordering ::= "ordered" | "unordered"
-distance ::= non-negative-integer
-
-qualifier ::= [ qualifier-prefix "." ] qualifier-name
-qualifier-prefix ::= identifier
-qualifier-name ::= identifier
-identifer ::= string
-term ::= string | ""string""
-string ::= a character string
-------------------------------- cut here -------------------------------
-
-Hope this helps, and that it's none of it's controversial. I guess it
-ought not to be, except maybe the change in the order of proximity
-parameters.
-
- _/|_ _______________________________________________________________
-/o ) \/ Mike Taylor <mike@miketaylor.org.uk> www.miketaylor.org.uk
-)_v__/\ The IBM 360 had no stack, and that was stupid, short-sighted
- design. The Cray 2 has no stack either, but that's elegant
- minimalism.
-
-
-
projects / cql-java-moved-to-github.git / blobdiff