Re: [office] Backwards compatibility?

["David A. Wheeler" <dwheeler@dwheeler.com>]

>> Daniel Carrera wrote:
>>> The recent discussion about style name uniqueness raises a more 
>>> general question: How much do we care about backwards compatibility? 
>>> Are we willing to change the format in a way that makes some 
>>> existing files invalid? Or do we want to guarantee that once a file 
>>> is valid it will always be valid?

Perfect guarantees are hard to provide, but I think we should preserve 
backwards compatibility unless there is a very good reason to do otherwise.

XML formats, like OpenDocument, are usually pretty easy to expand on.  
Just add a new attribute or tag; that won't invalidate the documents 
that don't use it.  If something wasn't specified clearly enough, then 
you can often appeal to existing practice and document it.  So backwards 
compatibility should often be fairly easy to achieve.

Now if there's a CRITICAL reason to make a big change, it's still 
possible.  Through namespaces, it can even be mostly invisible to 
users.  Given all the review, and the number of players, I don't expect 
that to happen often, though.

Currently, I expect a lot more work to going into clarifying what's 
underspecified (like formulas or angle units of measure), or adding 
whole new capabilities that don't interfere with existing documents 
(like most metadata).  The basics of office documentation are really 
stable; nothing really interesting or compelling has happened 
TECHNICALLY for 15 years at least.

--- David A. Wheeler