Re: Ada 0x Wish List

[Jeffrey Carter <jrcarter@acm.org>]

Peter Richtmyer wrote:
> 
> 1) In a Package Spec, it would be nice to be able to declare
> variables that are "constants' to other packages. that is, they can
> be "read" by other packages, but not written / updated. Code
> within the package (and child packages, etc) could update these
> variables like any other variables.
> 
> e.g.:
> 
>    Package A is
> 
>        B : constant Integer := 5;   -- normal constant
>        C : convar   integer := 8;   -- externally constant, internally
> variable
>        ...
> 
> Note the keyword "convar" is used for lack of a better keyword for now.

This already exists. It is called a function:

B : constant Integer := 5;

function C return Integer;

In the package body:

C_Value : Integer := 8;

function C return Integer is
   -- null;
begin -- C
   return C_Value;
end C;

If this causes timing problems compared to a global variable you can
inline C.

-- 
Jeff Carter
"Perfidious English mouse-dropping hoarders."
Monty Python & the Holy Grail