Re: Bug in GNAT?

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

----- Original Message ----- 
From: "Victor Porton" <porton@ex-code.com>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: November 09, 2002 4:01 AM
Subject: Re: Bug in GNAT?


> In article <mailman.1036834503.25329.comp.lang.ada@ada.eu.org>,
> Michal Nowak <vinnie@inetia.pl> writes:
> > 
> > On 2002-11-09 at 11:56 porton@ex-code.com wrote:
> > 
> >>GNAT-3.14p compiles the following without error-messages.
> >>Is it a bug in GNAT or in Ada Standard?
> > 
> > Neither one.
> > 
> >>function F(A: Integer) return Integer is begin return 1; end;
> >>Y: Integer renames F(3);
> >>
> >>Seemingly GNAT parser "thinks" that F(3) is an array element
> >>:-)
> > 
> > No, it thinks it is renaming an object.
> > See Reference Manual, 8.5.1 Object Renaming Declarations:
> > 
> > 1 An object_renaming_declaration is used to rename an object.
> > 
> > Legality Rules
> > 4 The renamed entity shall be an object.
> > 
> > The function F is returning an object of type Integer. 
> > So, if you invoke F(3) you get an object in result and then
> > you rename it to Y. 
> > Feeling beteer? :-)
> 
> But this compiles with an error:
> 
> function F(A: Integer) return Integer is begin return 1; end;
> Y: Integer renames F(3)+2;
Renaming declarations (according to the Ada Reference Manual)
can only rename a _name_.  Thus, since F(3)+2 is not a name,
but F(3) is a name, the behavior you are observing is legal.

Read the syntax definitions for Renaming_Declarations in
8.5 through 8.5.6, and the definition of Name in 4.1

> 
> What is the difference?
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