Re: 'SIZE attribute of a type

[iWarp.intel.com|ichips!intelhf!agora!markb@uunet.uu.net (Mark Biggar)]

In article <5898@email.sp.unisys.com> parkhill@email.sp.unisys.com (parkhill) w
rites:
>>parkhill@email.sp.unisys.com (parkhill) writes: 
>>>Image a compiler was smart enough to understand baised number ranges. 
>>>   type b is range 9 .. 10; 
>>>        or 
>>>   type b is range 2**31 - 2 .. 2**31 - 1;
>>>If the compiler can generate code that only uses 1 bit then b'Size 
>>>should return 1.
>My point on the compiler having the capability to use one bit is that I
>find the utility of type_name'size is now questionable.  Lets say the
>compiler is capable of using 1 bit but won't do it in most situations.
>How can any programmer use type_name'size to any practical purpose?  It 
>seems less useful than Entry_Name'Count.  However, I am sure that the 
>justification for the change to type_name'size is rock solid.

I don't thing anyone would implement this as an automatic feature of an Ada
 compiler.  But, it is perfectly reasonable for the rep-clause

 for b'size use 1;

 to cause a compiler to do just what you want, while not having the
 rep-clause would make b'size something like 8, 16 or 32.

 b'size is the actual storage used for the type not the minimum possible.

 --
 Mark Biggar
 markb@agora.rain.rain.com