- From: Kohsuke KAWAGUCHI <k-kawa@bigfoot.com>
- Date: Thu, 29 Mar 2001 12:55:39 -0800
- To: Alexander Falk <al@altova.com>
- Cc: w3c-xml-schema-ig@w3.org, www-xml-schema-comments@w3.org
I really appreciate WG members and James Clark who picked up my grief. I'm looking forward to see these BNF/RegExp in the spec. I suggests use of BNF rather than RegExp. RegExp is good for "approximation", but when it comes to precise definition, RegExp tends to become longer and thus illegible. Illegible expression is also difficult to check by humans. For example, in "duration" type, any component can be omitted as long as at least one is present. And 'T' must be present if and only if one of H,M,S is present. It's impractical to precisely express this constraint by using RegExp. Y M? D? (T (H M? S?) | (M S?) | S )? | M D? (T (H M? S?) | (M S?) | S )? | D (T (H M? S?) | (M S?) | S )? | T H M? S? | T M S? | T S BNF is more legible. duration := <YMDPart> T <HMSPart> duration := <YMDPart> duration := T <HMSPart> YMDPart := Y M? D? YMDPart := M D? YMDPart := D HMSPart := H M? S? HMSPart := M S? HMSPart := S regards, ---------------------- K.Kawaguchi E-Mail: k-kawa@bigfoot.com
Received on Thursday, 29 March 2001 15:55:16 UTC