Re: Attributes 'Version and 'Body_Version

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

O.K. You can get there from here. Sort of. If you dutifully record every
version string of a released component you at least know the valid history
and you can check against it. But I still think this is not as useful.

Example:

package Somepackage is    --  Version 1.0 (my number)
    A, B, C : Integer ;
end Somepackage ;

package Somepackage is    --  Version 2.0 (my number)
    A, B, C : Integer ;
    D, E, F : Integer ;
end Somepackage ;

So assuming I know something about when features are introduced and that my
project (attempts to) maintain upward compatibility and all that, what, if
anything, might I know about Version 1.5? If I know that D, E and F were
introduced in 2.0 and my calling module detects 2.0 *or greater* then it is
O.K. to use D, E and F. If it sees a module that is *less than* 2.0, it
knows not to use D, E and F. If, for some reason, a 1.5 version were to
exist out there, I'd know by the order that it wasn't compatible.

Granted, this is a contrived example and the compiler would catch any
invalid use of D E and F (thank you, Ada.) But one can easily imagine cases
that are more complex in which an ordered version string would help.

It isn't a perfect thing and it isn't a substitute for good configuration
management and knowing what is going on with one's software, but I could
imagine situations where this might be helpful if it were ordered. You can
always Roll Your Own and this may, in some circumstances, be a better idea.
(What causes the 'Version or 'Body_Version to be incremented? Every time you
edit the file? Every time you compile it? Every time there is some semantic
difference? What if you revert to a prior version of the file? What if you
need to be compiler-independent? Etc?) The weaknesses of 'Version &
'Body_Version may make it impractical for some uses - but making it Ordinal
would probably have been a good thing. (Any reason *not* to make it
Ordinal?)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Vincent Marciante" <marciant_remove@li.net> wrote in message
news:W4fG7.11237$ym4.493547@iad-read.news.verio.net...
>
> But you do know the order order of earlier versions and can store that
list
> in each new version othe code.  You also know that any version that was
> not a past version (not in the stored list) must be a new version and can
> then
> deside what to do in that case (this case will only come up when a past
> version of the code is attempting to work with a newer version )
>