Re: syntaxic exploration

["Randy Brukardt" <randy@rrsoftware.com>]

"Mehdi Saada" <00120260a@gmail.com> wrote in message 
news:0d33e631-e63d-4346-ac95-5eec72127f4f@googlegroups.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

Correct. You can't write this, because the iterable item could disappear in 
the body of the loop. (If someone assigned a different value to the mutable 
variable.)  This is the same rule as used for renames (you can't rename this 
component, either, for the same reason).

...
> 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 ?

'Range is rather a wart in the language; it can only be used in a few 
specific places. That's because X'Range is neither a subtype constraint nor 
a value, and those are the only things with general rules.

However, an aggregate choice is one the places that 'Range can be used, so 
you're obviously doing something else wrong. (Which I can't see given the 
partial code here.)

                                Randy.