Re: [SPARK] Code safety and information hiding

["Jeffrey R. Carter" <spam.not.jrcarter@acm.not.spam.org>]

Maciej Sobczak wrote:
> 
> It's interesting to see this discussion, especially after the posts 
> revealing that it's not really clear what "global" means.

We were discussing "true" global variables: variables in package 
specifications.

> Let's say I have a program composed of some subroutines or packages. 
> Each subroutine has some local variables and each package has some state 
>  and together they all cooperate according to what the whole is supposed 
> to do.
> Then I decide to break the system into separate processes, and for the 
> sake of discussion what was a subroutine (or a package) originally 
> becomes a separate process, all communicating using some form of IPC and 
> still cooperating to achieve the supposed goals.

Now each main subprogram that was a subprogram (Ada doesn't have 
subroutines) in the original has its own local variables.

Each main subprogram that was a package with state now has its own local 
variables that contain that state.

> The point is that while chopping the system into pieces, what was local 
> (or state) variable originally became global in the resulting smaller 
> program.

I don't see that this is necessary.

-- 
Jeff Carter
"What I wouldn't give for a large sock with horse manure in it."
Annie Hall
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