Re: Modest proposal, 2 of 3

[stt@houdini.camb.inmet.com (Tucker Taft)]

Van Snyder (vsnyder@math.jpl.nasa.gov) wrote:

: ...
: PROPOSAL for next standardization of Ada

: Allow objects to be declared in the public part of a package
: specification with mode "out".  The meaning is that clients of the
: package can reference the variable, but can't store into it.

This can pretty much be accomplished in Ada 95 as follows:

   package P is
       type T is private;
       type T_Reader is access constant T;
       Read_Only_Global : constant T_Reader;
     ...
   private
       Global : aliased T;  -- Global variable
       Read_Only_Global : constant T_Reader := T'Access;
   end P;

You could also create a rename of "Read_Only_Global.all" if need be,
perhaps in a child package.

: ...
: What fraction of Americans believe   |  Van Snyder
: Wrestling is real and NASA is fake?  |  vsnyder@math.jpl.nasa.gov

--
-Tucker Taft   stt@inmet.com   http://www.inmet.com/~stt/
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