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Newsgroups: comp.lang.ada
Date: Mon, 12 Feb 2018 16:01:43 -0800 (PST)
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Subject: Re: troubles learning OOP: expected type "Parent.Some_Child", found
 type Parent'Class
From: Mehdi Saada <00120260a@gmail.com>
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Xref: reader02.eternal-september.org comp.lang.ada:50405
Date: 2018-02-12T16:01:43-08:00
List-Id: <comp.lang.ada>

Ah !! Thanks, you made remember I could do, which works:
case GET_ELEM (T_Token_Operateur(I.all)) is
I used to think that conversion from a class-wide type to a child type need not ever be explicit, I was wrong, and it's safer that way of course.
It's better to use as little redispatching or dynamic whatever as possible. I did:

ELEMENT : Character renames STRING_VECTOR(Current_Index);
case ELEMENT is
when '(' => V_LOCAL (I) := new T_TOKEN_PARENTHESE'(La_Parenthese => '(');
when ')' => V_LOCAL (I) := new T_TOKEN_PARENTHESE'(La_Parenthese => ')');
when ';' => V_LOCAL (I) := new T_TOKEN_TERMINATEUR'(Le_Terminateur => ';');
I could do the same with '+' | '-' | '*' | '/',
but it would suck. I so want something like
when '+' | '-' | '*' | '/' => V_LOCAL (I) := new T_Token_Operateur'(L_Operateur => T_Operateur(ELEMENT));
But the conversion isn't valid, as I said. This is my last error, said the compiler. Thanks to you.