Re: Efficiency of code generated by Ada compilers

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 10 Aug 2010 14:26:25 +0200, Phil Clayton  
<phil.clayton@lineone.net> a écrit:
>   A(A'Length - I - 1)
>
> (not valid Ada, of course.)

A(A'Last - (I - A'First))

> Perhaps "reverse" would be a better name for the operator "not" when
> the modulus is not a power of two?
Or "wrapped" ? But this would only make sens on an array instance basis,  
not on type basis. If the array actual range is not the same as the index  
type range, it fails. So this could not be a type primitive (operator).  
May be an array attribute ? A'From_Last ? A'Last_Based ?

"reverse" is already there for loop statements. I feel this makes for sens  
for loop, as what is reverse, is not the array index: this is the  
iteration which goes reversed order.

-- 
There is even better than a pragma Assert: a SPARK --# check.
--# check C and WhoKnowWhat and YouKnowWho;
--# assert Ada;
--  i.e. forget about previous premises which leads to conclusion
--  and start with new conclusion as premise.