Re: A new notion: stronglly-typed-by-user language

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 18 Kwi, 22:38, Gautier write-only <gautier_niou...@hotmail.com>
wrote:

> - in C++, is it possible to do arithmetic with the (or a) boolean
> type, or convert silently from/to integer ?

Yes, bool is promoted to int (false->0, true->1) when used in mixed
context.

> - in C++, is it possible to assign a value of a type enum1 to a
> variable of type enum2,

No. Enums are distinct types and assignment between them requires
explicit conversion.

> or is it possible to do any mix or arithmetic
> without something like enum1'Pos ?

Enums can be promoted to int, so you can do "arithmetic" on them.
But you would not be able to silently assign the result back to enum,
as conversion from int (the result of "arithmetic") would have to be
explicit.

That is, you cannot use these tricks to silently subvert the type
system to mess the value of the enumeration type.

--
Maciej Sobczak * http://www.inspirel.com

YAMI4 - Messaging Solution for Distributed Systems
http://www.inspirel.com/yami4