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From: tmoran@acm.org
Newsgroups: comp.lang.ada
Subject: Re: data types & efficiency
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> to enforce the indepence from compiler in terms of their internal
> representation.
> So I will define for example:
>
> type UNSIGNED_INT_32_TYPE is range 0..(2**32)-1:
> for  UNSIGNED_INT_32_TYPE'SIZE use 32;
>
> to be used instead of the predefined Integer type.
  Usually people want their program to *run* the same regardless of
which compiler compiled it.  You seem to want its data area to be
the same size, the maximum size any compiler might use.  Why is that?
  Thus a program to play cards might define
    type Suite is (Clubs, Diamonds, Hearts, Spades);
A memory optimizing compiler on a suitably addressable architecture
might use 2 bits.  Another compiler on another machine might use 32.
Why do you require that they both use 32 bits to represent the four
possible values?
  For Integer, don't use the predefined type and assume it's, say, 32
bits.  Instead declare your own
  type home_thermostat_F_settings is range 55.. 90;
  type person_numbers is range 0 .. 50_000_000_000;
and let different compilers on different architectures use different
storage arrangements - your data values will never fall outside those
ranges so any extra bits are immaterial to the correct running of
your program.