From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_40,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,4ee5611d3fbf05b7
X-Google-Attributes: gid103376,public
From: rracine@draper.com (Roger Racine)
Subject: Re: Enumeration literal visibility and use type
Date: 1998/05/26
Message-ID: <rracine.3.000B9635@draper.com>#1/1
X-Deja-AN: 356663314
Distribution: na
Sender: nntp@news.draper.com (NNTP Master)
References: <6kej65$dnh$1@hermes.seas.smu.edu>
Organization: Draper Laboratory
Newsgroups: comp.lang.ada
Date: 1998-05-26T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <6kej65$dnh$1@hermes.seas.smu.edu> bralick@seas.smu.edu (William 
Bralick) writes:
>By now I have convinced myself that the following does not work as I had 
>hoped:

>-- we are provided the following package and required to use it to 
>-- interface with other subsystems

>package doodah is

>  type state_value_type is (state0, state1, state2, state_etc);

>  -- and just to make things interesting, let's create a useful message

>  type useful_message is record
>    state_stuff : state_value_type;
>    other_stuff : natural;
>  end record;

>end doodah;

>---

>with doodah;
>procedure test is

>   use type doodah.cool_type;

>   a_cool_message : useful_message;

>begin

>   a_cool_message.state_stuff := state0;  -- SIRENS WAIL, LIGHTS FLASH
>                                          -- COMPILER WANTS: 
>                                          -- doodah.state0

>   ...

>end test;

>---

>For some reason that I have yet to fathom, I had convinced myself 
>that "use type" would give immediate visibility of the enumerals in 
>doodah.cool_type.  I am now convinced that it doesn't (though I am
>ready to argue that it _should_).

Section 8.4 of the Ada RM:

"a use_type_clause achieves direct visibility of the 
primitive operators of a type."

Enumeration literals are not operators.

Roger Racine