Re: Noob question: universal_integer type

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

Le Sat, 22 May 2010 01:15:19 +0200, Duke Normandin <dukeofperl@ml1.net> a  
écrit:

> Coronado's Ada tutorial - Chapt3
>
> [quote]
> The constant 17 is of a very special type defined by Ada as type
> "universal_integer" which can be combined with any of the integer types
> without specific conversion.
> [/quote]
>
> Let me get this right... if I use an undeclared integer in an expression,
> Ada will "deem it" to be a "universal_integer" and not choke at
> compile-time?
On this subject, you may like to read a previous thread named “Integer  
questia”.
Here is a Google Group link for conveniance:
http://groups.google.com/group/comp.lang.ada/browse_thread/thread/d9d2bccce5d4fc93#

The key, is that universal integer, is a type like other types you may  
defined. Every type integer-like type can be converted to and from  
universal integer.

So, yes, the compiler will not complain, because if you have

    My_Constant : constant := 1; -- Named number, that is here, universal  
integer.
    type My_Integer_Type is range 1 .. 9;
    My_Entity : My_Integer_Type := My_Constant;

the compiler will not see a contradiction, it will not see the declaration  
of a given type which is initialized with a value of a different type, it  
will see a literal, which it will automatically convert to the target type.

-- 
There is even better than a pragma Assert: a SPARK --# check.