Some notes on Rust

[Paulo Pinto via Digitalmars-d]

On Saturday, 7 February 2015 at 09:13:19 UTC, Ziad Hatahet wrote:
> On Fri, Feb 6, 2015 at 12:08 AM, Paulo Pinto via Digitalmars-d <
> digitalmars-d at puremagic.com> wrote:
>
>> For example no need to check if a variable is inside a 
>> specific range, if
>> the type only allows that range.
>>
>>
>>
> Are you referring specifically to Ada here? Otherwise, how 
> would ML-based
> languages allow for this in a way that your traditional OO 
> languages would
> not?
>
>
> --
> Ziad

Mostly Ada. An example in Ada taken from WikiBooks
(http://en.wikibooks.org/wiki/Ada_Programming/Type_System#Subtype_categories)

package Device_Driver is
     type Size_Type is range 0 .. 64;
     type Register is record
        A, B : Boolean;
        Size : Size_Type;
     end record;

     procedure Read (R : out Register);
     procedure Write (R : in Register);
end Device_Driver;

Any attempt to assign anything outside 0..64 range to Size will
trigger an error, either at compile or run-time.

As for ML languages I was thinking that similar constraints can
be expressed via dependent types, in the variants that allow
them, but never used them.

--
Paulo