Re: Declarative constraints in practical terms

dawn wrote:
[....]

> I lean toward not duplicating constraints, coding and maintaining them
> in multiple places and languages, but I understand that someone else
> might choose the other strategy. Whatever choice, it doesn't look
> obvious to me that declarative constraints are better as I gather it
> appears to many others.

Dawn - I hold you are exhibiting the classic "all eggs in one basket" mentality that afflicts the average [those below average are unlikely to know what constitutes an egg :-)] IT practitioner and which I frequently also characterise as the "fair weather sailor" mentat.

Firstly, please, please promise me you will never ever design or build an aircraft that I might ever be likely to ever fly in (or stand under).   Aircraft today (as in the past) have all critical systems in a double or triple redundant arrangement and I deeply suspect yours won't have any redundancy at all!

The same thinking can be applied to "declarative constraints" in IT system building. IMO it is simple first order thinking to presume a single layer of constraints is going to be adequate to secure a system against decay. Building software is an engineering activity and should be approached in the same critical fashion - with some degree of over-engineering commensurate with the risk.

Therefore the correct discussion is not about "better" in a singular sense such as you use it above, but using combinations of techniques to achieve the "best". Dismissing the declarative approach out of hand on a pretext is not ever going to reach that best outcome.

> This relates to the fact that the RM is not sufficient for writing
> software (as mentioned in my current blog entry that I'll again boldly
> advertise as being at http://www.tincat-group.com/mewsings ) and coding
> constraints using the RM doesn't seem like it can get you all the way
> there. So if you go that route, you end up duplicating your work, both
> up front and for all maintenance.

ibid.

> Is there a way to get the best of both worlds on this one?

Some will argue that there are better forms and places (than others) to make your investments. Regardless which is promoted over any other, I argue that diversity and hedging your bets is a very useful survival trait.

So drawing from "both worlds" is ideal rather than an a negative antagonistic event - IMO.

> This issue
> is really bothering me, so thanks in advance for any help you can give
> me to gain a better understanding and apologies for bringing it up
> again.

On a more philosophical note having read your past posts and conversed on several threads I have formed a view that you are ensconced in a comfort zone with MV and subsequently seek to justify that state of affairs mostly by trying to comparatively write off the RM rather than by simply promoting the virtues of MV. I know comparative treatment is a useful tool but in your hands it always seems to come down as black, rarely white and never shades between!

It seems to me no matter what evidence or logical deductions are presented that this state of affairs will not change. Consequently I find interesting that you bother to project any ambivalence at all on these subjects.

Cheers, Frank. Received on Wed Feb 22 2006 - 04:22:47 CET