Peter Dimov wrote:
Joel de Guzman wrote:
Peter Dimov wrote:
Joel de Guzman wrote:
Peter Dimov wrote:
I can't help but wonder: if some parts of your v1 format are so completely redundant as to allow you to reconstruct the original data even if you skip them, what was the point of writing them in the first place? Here's one scenario (I'm sure there are others): Your class uses a 3rd party library called Y. Later, you decide to replace it with a better engine using a library called Z. Still not getting it. Do you have an example? That was the example ;)... Ok let me see if I can clarify... With version 1 you have a class A with this structure:
class A { W, w, X x; Y rep; };
Now with version 2, you want to use a new engine to replace Y:
class A { W, w, X x; Z rep; };
Z is so different from Y that it does not need any of its data. It is also plausible that W,X,Y and Z get some data from other external sources. So, in effect, Z starts with a default data and gets filled as the app runs.
Right. What I was saying is that if the pair (w, x) is all you need to reconstruct an A, then there is no need to store the Y part (except short-term convenience).
Good point! Maybe I ought to review the situation. It might be that what's actually needed in this case is a converter from Y to Z. Regards, -- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net