- From: Ian Hickson <ian@hixie.ch>
- Date: Thu, 20 Jan 2005 12:41:57 +0000 (UTC)
- To: Bjoern Hoehrmann <derhoermi@gmx.net>
- Cc: www-qa@w3.org
On Wed, 19 Jan 2005, Bjoern Hoehrmann wrote:
>
> Suppose you want to restrict something to "#" followed by six hex digits
> case-insensitively; the formal language can only express this by listing
> all 113,379,904 values
That rather depends on the formal language. You could describe it in some
language as:
'#' [a-fA-F0-9]{6}
> [Having the formal language express the syntax approximately because of
> limiations in that language] would cause formal language and prose to be
> inconsistent and there is no sane way to remove the conflict without
> prose that lets one part override the other. Your proposal is thus
> paradoxical, you need to violate it in order to implement it (you would
> need prose that states this is a known inconsistency and the prose is
> normative, for example.)
In cases where the formal language is inadequate for describing the actual
requirements, then indeed, it should be informative. My comment was
directed more at the common case of the formal language being just as
expressive as the English prose, but one being (mostly arbitrarily or
politically) chosen as the normative one.
That is, I was talking more about unintentional conflicts than known
conflicts due to limitations of the formal language.
In my work with various working groups I have found it to be substantially
easier to deal with cases where the spec was internally inconsistent, than
in cases where an informative part of the spec contradicted a normative
part (and the normative part was the one in error).
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 20 January 2005 12:41:59 UTC