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Message-ID: <3feda44e_3@mk-nntp-1.news.uk.worldonline.com>
From: Ian Bell <ian@ruffrecordsDOTworldonline.co.uk>
Subject: Re: Certified C compilers for safety-critical embedded systems
Newsgroups: comp.arch.embedded,comp.lang.ada
Followup-To: comp.arch.embedded
Date: Sat, 27 Dec 2003 15:27:53 +0000
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Date: 2003-12-27T15:27:53+00:00
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James Rogers wrote:

snip
> 
> type my_index is range 0..9;
> type My_Array_Type is array(my_index) of integer;
> 
> foo : My_Array_Type;
> 
> for num in 0..99 loop
>    foo(num) := num;
> end loop;
> 
> All Ada compilers will correctly identify the error in the for loop.
> The type of "num" is not the same as the type of the index, because
> the range of values defined for "num" are not all within the range of
> values in my_index. This detection will happen properly no matter how
> far the definition is separated from the "for" loop.
> 

I know nothing about ada so this is a genuine query rather than a ctiticism. 
The above example is fine as long as literals are used - even a C compiler
could be devised to make this check - but what happens when the array index
is computed?

Ian