Re: Reduction expressions

Lawrence D'Oliveiro <ldo@nz.invalid> writes:
[...]

I thought the difference was obvious. “subtype” is the C equivalent of
“typedef”, just giving a new name to an existing type. So
>
    subtype A is B;
>
(where A and B are simple identifiers) is valid, whereas
>
    type A is B;
>
is not: a “type” declaration always creates a new type: you have to write
at least
>
    type A is new B;
>
and now you have two types with different names that are structurally the
same, but not compatible.

A subtype with no added constraint is similar to a C typedef, but given

    subtype Digit is Integer range 0..9;

Digit is distinct from Integer (though they're both the same type).

C doesn't have anything directly corresponding to Ada subtypes.

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */