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From: Jacob Sparre Andersen <jacob@jacob-sparre.dk>
Newsgroups: comp.lang.ada
Subject: Re: In mode parameter in an assignment statement
Date: Sat, 13 Oct 2018 07:52:51 +0200
Organization: JSA Research & Innovation
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Date: 2018-10-13T07:52:51+02:00
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Anh Vo <anhvofrcaus@gmail.com> writes:

>    -- ...
>
>    ------------------
>    -- Compute_Data --
>    ------------------
>
>    procedure Compute_Data (Region : Mapped_Region) is
>       Data_Shift : constant Storage_Offset :=
>          Storage_Offset (Region.User_Offset - Region.System_Offset);
>    begin
>       if Region.User_Size = 0 then
>          Region.Data := Empty_String'Address;
>       elsif Region.Mapped then
>          Region.Data := Region.Mapping.Address + Data_Shift;
>       else
>          Region.Data := Region.Buffer.all'Address + Data_Shift;
>       end if;
>    end Compute_Data;
>
> end GNATCOLL.Mmap;
>
> The above code is the tail end of package gnatcoll-mmap.adb.
>
> I thought it should be rejected during compilation because in mode
> parameter is not allowed in an assignment statement. But, it was
> compiled successfully under GNAT obviously.
>
> What did I miss? Thanks in advance.

Probably that there is an access type involved.

If "Mapped_Region" is an access type, then "Region.Data" could be a
short-hand for "Region.all.Data".

Greetings,

Jacob
-- 
"I've got _plenty_ of common sense!"
"I just choose to ignore it."