Rob Sanderson writes:
 > On Tue, 2006-08-08 at 12:18 +0100, Mike Taylor wrote:
 > > Robert Sanderson writes:
 > >  > >The proposed substring function is really many functions in
 > >  > >disguise. I reckon it is at least five distinct functions:
 > >  > 
 > >  > At least.  But we don't really want 5 or more relation modifiers that
 > >  > each cover a small part of the functionality of substrings, do we?
 > > 
 > > I sort of agree with Ashley that this is overloaded; but I also agree
 > > with Rob that breaking it into five is not the solution.  I think that
 > > going to a 1-based index is a mistake, and that the consequent benefit
 > > of getting to use 0 to mean "the end" is too small to be worth the
 > > cost.  I think the proposal as it stands is just about right.
 > 
 > Which proposal are you talking about in particular?
 > 
 > The current version has not only 0 as both start and end, but -0 as the
 > start, and negative numbers being magical in the end position but not
 > the start!
 > 

Ouch!

 > I'm looking for a set of rules for start and end positions that have as
 > few special cases as possible, while being easy to understand and apply.
 > 
 > Also suggested to me was start,length
 > eg:
 > 	marc.008 =/substring="0,6" 920102
 > 
 > With negative numbers counting backwards.  This has no special cases, is
 > zero based and easy to apply.

This is what I thought was on the table.  I like it.

 _/|_	 ___________________________________________________________________
/o ) \/  Mike Taylor  <[log in to unmask]>  http://www.miketaylor.org.uk
)_v__/\  It's hard not to suspect that SOAP was thought up late one Friday
	 night after a few too many beers.