On Thu, Jul 05, 2018 at 02:51:58PM +0530, K K Subbu wrote:
> On Wednesday 04 July 2018 09:23 PM, David T. Lewis wrote:
> >A clue that this might be accumulation of kludges: Looking at senders of
> >selectInvisiblyFrom:to: (such as TextEditor>>addText:event:) shows a number
> >of methods that subtract 1 from the stop index when before calling the 
> >method
> >that adds 1 back to the stop index. This certainly does not have a good 
> >smell.
> Looks like different intervals for dealing with selections and 
> substrings. I see that the names used are start/stop instead of 
> startIndex/stopIndex. I found this consistent pattern in all methods 
> that deal with selections.
> 
>   stop = (stopIndex - 1)
>   stopIndex = (stop + 1)
> 
> Regular methods that deal with substrings like 
> AbstractFont>>#widthOString... and BitBlt>>#primDisplayString... and the 
> scanner methods iterate over aString with:
> 
>    startIndex to: stopIndex
> 
> while Editor>>selectionInterval extracts selections with startIndex to: 
> (stopIndex-1).
> 
> Regards .. Subbu
>

Ah yes, that makes sense now. Thank you for the explanation.

Dave