declaration section of ABNF


A couple or remarks:

1. Order of declarations. It was fixed in the previous Draft and now
   (in the candidate recommendation) declarations may appear in any
   order.  Actually I find this freedom harmfull for readability: if
   you're used to find always base, language, mode, root, tagFormat,
   lexicon, and meta, then getting the declarations of a new grammar
   is just easier; and writing a new grammar is just as simple.  From
   a software engineering point of view, it's like parameters for a

   To me, making the order free helps only beginners as grammar
   writers; it's useless if you're not a beginner and it's confusing
   if you're not a writer but a reader.

2. Tag format.  The candidate recommendation states that, for a given
   grammar, lexicon and meta declarations may appear any number of
   times, that language must appear exactly once, but it doesn't state
   that tag-format can appear at most once (which is stated for base
   and root) and I don't think that several tag-format declarations
   make any sense.
   [this can be solved syntactically: by reintroducing the fix order
   of declarations and making tag-format optional at its place, as it
   was in previous version of the document!-)]

   Furthermore, the tag-format should be like the mode: you cannot
   have a grammar in voice mode that uses a rule from a grammar in
   dtmf mode.  Similarly, I don't think you can mix two grammars that
   have different tag formats. Well, you could but it would require
   that further specification of tags is provided in the document.
   Currently, the tag language is defined externally: not only the
   syntax of this language but also its semantics, the kind of
   computed information (character strings, objects, raw data,
   attributes...), the data format, the way information is processed
   along the Logical Parse Structure (Appendix H), i.e. along the
   parse-tree (top-down, bottom-up, depth-first traversal,...), and
   everything I'm forgetting...

   I'd suggest mixing tag formats is forbidden like mixing modes.


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Received on Wednesday, 10 July 2002 08:03:57 UTC