syntaxic exploration

[Mehdi Saada <00120260a@gmail.com>]

I'm being modelizing polynomes. I've got those two things: p_poly_v1_g.adb:51:21: iterable name cannot be a discriminant-dependent component of a mutable object
Ah ? So I can't write that ?
return RESULTAT : T_POLYNOME := POLY do
        for ELEMENT of RESULTAT.COEF loop
                ELEMENT := - ELEMENT;
        end loop;
end return;

I've got that too:
p_poly_v1_g.adb:59:86: selector name should be identifier or "others"

return RES: T_POLYNOME := (T_DEGRE'MAX(POLY_A.DEGRE,POLY_B.DEGRE),POLY_A.COEF'Range => POLY_A.COEF, others => Nulle) do

I thought X'Range was strictly equivalent to X'First..X'Last ? Of course, poly is a mutable article, with two components, Degre (derived from NATURAL), and COEF, array. 

I have that too:
for IND in POLY_R.COEF'Range loop
      POLY_R.COEF(IND) := POLY_R.COEF(IND)*(IND+1);
end loop;

COEF's elements of T_RATIONNEL type, themselves record types. IND is of type T_DEGRE, so why do I have that:
p_poly_v1_g.adb:73:43: expected type "Standard.Integer"
p_poly_v1_g.adb:73:43: found private type "T_Rationnel" 

Thanks !