Re: An observation of Ada (may offend)

[dweller@Starbase.NeoSoft.COM (David Weller)]

In article <3ku7us$117l@info4.rus.uni-stuttgart.de>,
Peter Hermann <ucaa2385@alpha1.csv.ica.uni-stuttgart.de> wrote:
>Robert I. Eachus (eachus@spectre.mitre.org) wrote:
>:     Of course, and the reason for posting this, is that one needed
>: form of the pragma is "pragma Child_Units(None);" or "pragma Child_Units;"
>: I perfer the second form, what do the rest of you think?
>
>I would not recommend that whole direction because
>one of the strengths of the child feature is exactly the fact,
>that the parent need not be touched further on.
>For Ada200X, the abs private part may be more convenient (if any)
>but, imho, this overburdening of the language is superfluous.
>

Ah, but that's what pragmas are for, eh? :-)

The way I see it is you have three options:
1.  Anybody can extend your package
2.  Nobody can extend your package
3.  Specific "children" are permitted to extend your package

Option 1 is definitely supported in Ada95
Option 2 and 3 can be supported with Eachus' suggestion (giving a
"friend"-like pragma)

The fundamental issue is, however, can you thwart options 2 or 3?
Given the pragma Robert Eachus suggestied, the answser is "No" for
pragma Child_Units(None) and "yes" for Pragma Child_Units(..list..).
All I have to do for option 3 is create a child unit that has a
matching name.

It kinda leads me to conclude that perhaps just having a "pragma
No_Child_Units;" is the best thing to have.

Maybe this discussion should migrate to the MRT list?


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