Re: private types

[Justin Gombos <rpbkbq.xax.gld@uluv.kbq>]

On 2006-03-17, Maciej Sobczak <no.spam@no.spam.com> wrote:
>
> So you have the whole pragma as such "disservice":
>
> http://www.adaic.org/standards/95aarm/html/AA-H-1.html

I don't have a problem with implicit initializations when the compiler
can ensure a bad value (or "abnormal object", to use the language of
the ARM).  I was responding to Brian May's comment about compilers
implicitly assigning "dummy values", which did not sound to me like
values that are intelligently selected to be invalid for the type.
I've heard of compilers implicitly initializing to zero, and figured
that was what he might be advocating.

BTW- I sometimes have a use for creating an abnormal object, and find
     Ada lacking in not providing such a mechanism.  I'm sometimes
     forced to either include abnormal values in the set of values
     declared for a type, or to have a seperate flag.  Both of these
     are messy.  Why not have a 'invalid function added to Ada to
     enable simple and explicit initialization of abnormal objects?

> Right. Then, why not minimize the scope of the object to the extent
> when it's never even visible before being initialized with the value
> that is meaningful in the given context? It's not always possible,
> of course, but in many (most?) cases programmers tend to put all
> variables at the beginning of some rather coarse-grained scope (for
> example, beginning of the procedure or function), and later wonder
> what is the "right" initial value for them. It's the misplacement of
> declaration that is a primary source of problems and this is what
> should be actually addressed.

I agree.  Declare blocks can eliminate some of these issues.  I like
the fact that declare blocks enable me to declare more constants than
variables.  But it's not a full solution.  The opposite extreme of
this would be to introduce a declare block at every introduction of a
new object, which can obviously become detrimental to readability.
It's a trade off that requires judgement - judgement that is unequal
among adaists.

> Single entry - single exit syndrome? :)

Yes, I have that syndrome.  I think I acquired it from the Ada Quality
and Style Guide or a coding standard that I followed at one point.

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