Re: Ada vs Fortran for scientific applications

[<adaworks@sbcglobal.net>]

"Jeffrey Creem" <jeff@thecreems.com> wrote in message 
news:ghfco3-4am.ln1@newserver.thecreems.com...
> adaworks@sbcglobal.net wrote:
>> "robin" <robin_v@bigpond.com> wrote in message 
>> news:z9Dsg.2740$tE5.2374@news-server.bigpond.net.au...
>>
>>>Compilers can check for uninitialized variables during compilation.
>>>
>>
>> True.  In fact, Ada compilers issue a warning for any variable
>> that is used before a value is assigned to it.    If a parameter is
>> included in a method (function/procedure/subroutine) and never
>> referenced, a warning is issued.
>
> Which LRM section requires that? (Since "Ada compilers" do it, I assume it is 
> a requirement of the LRM?) Since I'd like to have it removed or ammended to 
> require meaningful operation of pragma suppress warnings.
>
Notice that I used the word "warning."    An Ada compiler can detect a lot
of information due to very nature of the language.   In fact, one of the design
goals of Ada is to detect the maximum number of errors as early in the
development process as possible.   Consider the following code:

      with Ada.Integer_Text_IO;
      procedure Unitialized_Variable is
             function F1 (A : Integer; B : Float) return Float is
                  Temp : Float;
             begin
                    return Temp;
             end F1;
             X, Y, Z : Integer;    -- unitialized variables
      begin
          Y := X;
          Ada.Integer_Text_IO.Get(X);
          Z := X;
      end Unitialized_Variable;

The compiler issues a warning, "...X may be used before it has a value."
For the function, it issues a warning that we have never referenced the
parameters A and B.  It also warns me that Temp is never assigned
a value.

These are not a fatal errors.    The Ada Language Reference manual does not
require this warning.   However, as mentioned above, the design of the
language makes it easy to issue such warnings.   Those of use who use
Ada quite a bit are happy to have a language which provides the maximum
of information we need to avoid making foolish mistakes. This may not be the
case with other languages, but it is the case with Ada.

Richard Riehle