I slipped into using the word "developers" here.
Perhaps I should clarify terminology.
StataCorp jargon is that the developers are those
technical people at StataCorp who produce official
Stata, i.e. the software you buy from them or
download by an -update-.
Stata programmers include anybody who writes a Stata program,
including developers and users. That is, you start by
writing something like
program define myprog
or, these days,
program myprog
Mostly that work, by users, remains outside official Stata,
although some does sooner or later get adopted as part of official
Stata. (Conversely, on occasion, the developers do make public
some of their programming work that is not part of official Stata,
or at least not yet.)
That said, the practices recommended to user-programmers on -version-
are precisely those followed by developers, so this
distinction is secondary to the advice below.
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 19 January 2004 10:13
> To: [email protected]
> Subject: st: RE: Version number in ado files
>
>
> Bluntly, this depends -- partly -- on how far one cares
> about making one's programs available to others.
> Richard has himself put stuff on SSC, so he does
> care. I also put stuff on SSC, so I care, although
> in practice life is sometimes too busy to accommodate
> all possible users.
>
> A Stata programmer writing a program afresh
> is likely now to be developing it with the 8.2 executable
> and 8.2 ados and as such to declare -version 8.2-.
> StataCorp work hard at enhancing the language and
> developers make life easier for themselves by
> exploiting new features to the full. Naturally
> anyone wanting to build on the new graphics or the new
> -ml- (say) has essentially no choice here. Conversely
> there are tasks that do not require newer features.
> Even then many programmers find the newest features
> -- even such more or less cosmetic details as // or /// --
> pleasant to work with, which blows compatibility even
> with Stata 7.
>
> Another common situation, however, is that a new
> program can be written as a minor variation on
> an existing program, which may well be declared
> as Stata 6 or Stata 7. Rewriting that to Stata 8.2
> may well be unnecessary: the best advice may well
> be "if it's broke, don't fix it". Thus often users
> add some small tweak to an official command and
> write -<command>2-, say. If -<command>- is a few
> dozen lines long and full of oldstyle stuff (say
> macro shifting rather than -forval- or -foreach-
> loops) it may be satisfying to rewrite it afresh.
> If it is a few hundred lines long, it is usually
> better to fix only what needs fixing (and even experienced
> programmers may well be wary of rewriting a long
> command: not only will it take time, breaking
> something by accident is a real risk).
>
> Yet another fairly common situation is that
> a Stata programmer is updating a program to
> Stata 8. One possible policy is to leave (say)
> -foobar- written for version 7 in place in an
> archive such as SSC as -foobar7-
> and to declare that frozen henceforth. This
> is a gesture to those still on Stata 7. (The gesture
> includes the advice to upgrade Stata!) Meanwhile
> -foobar- will now be the version for Stata 8.
>
> There are thus at least two conventions. A widely
> held convention is to imply that -<command>2-,
> -<command>3, etc. are successive (unofficial) improvements
> on -<command>-. A less widely used convention
> is that -<command>6- or -<command>7- mark
> _historic_ versions requiring at most Stata 6
> or Stata 7. The existence of these two conventions
> -- and I believe I am to blame for introducing the
> second -- is possibly a little confusing, but in
> practice most improved variants have numbers no
> bigger than 2, and I don't think anyone is now concerned
> with paying much consideration to compatibility
> with any version lower than 7, unless it is costless.
>
> Nick
> [email protected]
>
> Richard Williams
>
> > I have a question about version numbers in ado files: you
> > are supposed to
> > include the version # the ado file was developed with,
> > right? e.g. if I
> > wrote an ado file today, I should include a line that
> says -version
> > 8.2-. That guarantees it will keep working ok with later
> versions.
> >
> > But suppose that the ado file would have also worked fine
> > with version 7,
> > version 6, or whatever. Have I kept it from working with
> > earlier versions
> > because I included the line -version 8.2-?
> >
> > I just tried changing an ado file that said -version 6- to
> > -version 9-, and
> > sure enough, it said that it wouldn't work, and I would
> > have to upgrade my
> > version of Stata.
> >
> > Would it be considered good practice to try lower version
> > numbers on your
> > ado files, until they stopped working correctly?
> >
> > The version command is nice in that it keeps old programs
> > working, but it
> > looks like it may make you pay a price for not buying the
> > latest and
> > greatest version of Stata!
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