Re: Ranges and discriminant constraints

["AG" <ang@xtra.co.nz>]

"Vadim Godunko" <vgodunko@vipmail.ru> wrote in message
news:665e587a.0306071258.1a8711cc@posting.google.com...

> Does anybody explain me why language allow constraint discriminant of
> discrete type to some value, but not allow constraint to range?

If I understood you correctly you mean something like this: [?]

type abc is (a, b, c);
type test(y: abc) is record
  ...
z: test(a);      -- Which compiles
  vs
z: test(a..c);  -- Which doesn't

Assuming I did understand you correctly,
what would that construct do? The whole
point of a discriminant value is to select
one option out of available set. Ranges
as such are not true values in Ada (you
could do a search for a thread awhile
back which discussed arrays of "nothings"
which existed solely for the purpose of
passing their slices around just to implement
the ranges as variables).