Re: Range types

[Christos Chryssochoidis <C.Chryssochoidis@gmail.com>]

Thanks! This is indeed a very good solution to the problem I posed. And 
that's what I'll probably end up doing. I thought too about defining a 
function (predicate) that would decide whether a given value falls in 
the legal ranges. But by doing the discrimination with a function, I 
wouldn't have a "concrete" type to work with...

Thanks very much,

C.C.


anon wrote:
> --
> -- From the syntax rules of RM 3.2.1, 3.2.2 and 3.5 the 
> -- simple answer is no for integer scalar types.
> --
> -- One way to do this is to exclude the values you want 
> -- in the logical of the program
> --
> with Ada.Text_IO ;
> use Ada.Text_IO ;
> 
> procedure t is
> 
>     --
>     -- creates a master constraint type
>     --
>     type My_Int_Base is range 1..200 ; 
> 
>     --
>     -- creates an excluded type
>     --
>     subtype My_Int_Exclude_Subtype is My_Int_Base range 101..149 ;
> 
> 
>     Var_0 : My_Int_Base ;
> 
>   begin
> 
>     -- set Var_0  valid
> 
>     Put_Line ( "Var_0 => 75" ) ;
>     Var_0 := 75 ;
> 
>     --
>     -- Verify that value of Var_0 is not excluded
>     --
>     if Var_0 in My_Int_Exclude_Subtype then    
>       raise Constraint_Error ;
>     end if ;
> 
>     --
>     -- Use Var_0
>     --
>     Put_Line ( "    Var_0 => Valid" ) ;
> 
>     --   
>     -- Set Var_0 invalid
>     --
>     Put_Line ( "Var_0 => 125" ) ;
>     Var_0 := 125 ;
> 
>     --
>     -- Verify that value of Var_0 is not excluded
>     --
>     if Var_0 in My_Int_Exclude_Subtype then  
>       raise Constraint_Error ;
>     end if ;
> 
>     --
>     -- Use Var_0
>     --
>     Put_Line ( "    Var_0 => Valid" ) ;
> 
>   exception
>     when Constraint_Error =>
>       Put_Line ( "    Var_0 => Constraint_Error" ) ;
>   end t ;
> 
> 
> 
> In <1192994157.867598@athprx04>, Christos Chryssochoidis <C.Chryssochoidis@gmail.com> writes:
>> Hi,
>>
>> I have a question regarding the range types in Ada. Is there any way to 
>> specify that a type is, say, the values 1..100 and additionally the 
>> values 150..200? I tried something like
>>
>>> type My_Int is range 1..100, 150..200;
>>
>>
>> and
>>
>>> type My_Int is range 1..100 | 150..200;
>>
>> but without success. I also tried doing this within an enumeration, but 
>> failed again. Is it possible to define such type, consisting of multiple 
>> ranges?
>>
>>
>> Thanks very much for any answer.
>>
>>
>> Christos Chryssochoidis
>