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From: "G.B." <bauhaus@notmyhomepage.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Ada needs some modernization
Date: Thu, 2 Jun 2022 07:56:53 +0200
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On 31.05.22 19:54, Matt Borchers wrote:
> Throughout my career, I often find myself writing code similar to:
> 
> if (A and B) or else (not A and C) then...
> 
> and I always wished there was a better and clearer way to write this in Ada.  Then along came if expressions.  But, if expressions don't help that much with readablity although it is arguably simpler:
> 
> if (if A then B else C) then...
> 
> What amendment can we suggest to the Ada syntax so the if expression be better written when used in an if statement?

I would try to fix the problem at where it is caused: ad hoc, unnamed
logical predicates! Syntactic sugar won't make these go away.

All those Boolean expressions have meaning, I suppose. The meanings
could be given a name. There would be facts, about A, B and C, that
make your statement true, some not. What does it state?

Compare this assembly of variables

((A and B) or else ((not A) and C)))

to a lambda expression or to a state machine's. Similar?
It is the lowest level of computation using a high level language.


> Again, I often find myself writing a loop to search for something and then performing one or another action depending on the success of the search.  This almost always requires some externally defined variable, like:
> 
> --assuming arr'First is not Integer'First
> found := arr'First - 1;
> for i in arr'Range loop
>      if arr(i) = match then
>          found := i;
>          exit;
>      end if;
> end loop;

Again, there is an algorithm, typically Find_the_First, that will return
an index (or cursor). I'd use the return value in a conditional.