item delimiter defaults

[J. Landman Gay]

On 11/21/13 12:19 PM, Bill Vlahos wrote:

> The only problem I see in making this change now is that it will
> break some apps. If I give or get a stack from someone who defaults
> to a different delimiter things will break in funny ways.
>
> Perhaps there can be a statement in some standard place such as
> preOpenStack like “set the itemDelimiter to XXX” or a stack Custom
> Property. LiveCode IDEs after a certain date will read and set it and
> if it isn’t there the current behavior of comma will be used as the
> default. This would provide backwards compatibility without much
> overhead.

I use commas all the time, and so does the engine. The default delimiter 
for all native properties is comma (colors, rects, etc.) and changing it 
universally would break almost all legacy stacks.

However, that said, I think the original request was for the developer 
to be able to specifically set a global delimiter, which would be the 
correct way to implement this. The default global delimiter would be a 
comma, as it is now. But there would be a command to change that, which 
authors could use if they wanted it.

   set the globalDelimiter to tab

That could be executed anywhere in any script and would change the 
global propery until it was changed again. Legacy stacks would remain 
unaffected because the engine default would be comma as it is now.

I do think it will cause the same issues that we had in HyperCard, where 
setting the itemDelimiter was global instead of handler-specific. I 
welcomed the revised use of item delimiters back in MetaCard because I 
no longer had to bracket every change with saving the old one, using the 
new one, and then restoring the old one. Keeping the delimiter 
handler-specific was a godsend that made scripting much easier.

Providing a way to implement this older HC behavior could cause the same 
issues. Every time you want to extract the components of a rectangle, a 
color, or any other native property, you will have to do this:

   put the itemDelimiter into tOldDel
   set the itemDelimiter to comma
   put item 1 of tColor into tRed
   set the itemDelimiter to tOldDel

That's what we had to do in HC and I guarantee it's a pain in the patoot.

-- 
Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com