SCHEDULED for deprecation

[Nick Sabalausky]

<Tomasz Sowi&#324>; "ski" <tomeksowi.remove.this at gmail.and.this.com> wrote 
in message news:gtv3u0$2q00$1 at digitalmars.com...
> This phrase gave me an idea for a small feat:
>
> deprecated(2009-4-19) void foo();
>
> Compiling references to the deprecated declaration *before* the 
> deprecation date would result in a *warning*.
> Compiling the deprecated declaration OR any reference to it *after* the 
> date would result in an *error*.
>
> Advantages for maintanance are obvious, plus, the feature seems easy to 
> implement. What do you think?
>

Deprication should not work like that. Deprication should be based on 
versions, not actual dates. Basing it on dates like that can cause a number 
of different problems for, and can even be considered disrespectful to, your 
API's users. If/when you reach a point where you decide it's time for 
something to be depricated, you should put out a new release. Even if you 
have a way to know for certain that release will actually occur on-time, 
then there would clearly be no problem in just waiting until that point to 
put out a release that depricates the old stuff. Plus, that way you're not 
rudely attempting to force the hand of your API user. If they're ok with 
something being depricated, then they can upgrade to the newest version at 
their own will, whevever *they* decide it's time for *them* to do so.

As far as the idea of "deprication warning and then later a deprication 
error", we already have something that's...almost...just as good: If you get 
a deprication error but you're not yet ready to convert, there's a compiler 
switch to allow depricated stuff. However, I say "*almost* as good" because 
thanks to DMD's complete inability to treat warnings AS warnings (instead of 
always insisting on treating them as errors, 
http://d.puremagic.com/issues/show_bug.cgi?id=2567 ) it's impossible to get 
a complete list of depricated references in a program (and even that would 
only happen if deprications were able to be considered warnings at all).