Re: "Ada Gems": Constructor functions


Yes, you did find a GNAT BUG!

To find the line numbers and errors try

gnat1 t.adb -gnatl 2>t.lst
gnat1 test_t.adb -gnatl 2>test_t.lst

But to make a report to Adacore:
First compile using

gnatmake test_t.adb 1>1 2>2

-- Note: File '2' should have the error info that Adacore is
-- asking about.


Then send Adacore the following list of files

attach file => t.ads

attach file => t.adb

attach file => test_t.adb

attach file => 1

-- Note: Send File 1 only if it has any special info else skip
--

attach file => 2


I use Ada 95 to compile and did not receive the BUG ERROR
only a few normal compiling errors.

Now, for a compilable corrected version in GNAT Ada 95.
Did not use GNAT Ada 2005 compiler.

changes to code:
--- removed => denote the line is commented out
--- Added => denote the line is added to source
other comments added for info only


-----------
-- t.ads --
-----------
with Ada.Strings.Unbounded;
use Ada.Strings.Unbounded;

package T is
-- type Object (<>) is tagged limited private; --------- removed
-------- because can not initial
-------- a limited type in Ada 95

type Object (<>) is private; --------- Added

function Create_Object (Name : in String) return Object;
function Construct return Object;
function Name (This : in Object) return String;

private ------------------------------ Added
-- type Object is tagged limited -------- removed
-------- because can not initial
-------- a limited type in Ada 95

type Object is ------------------------ Added
record
Name : Unbounded_String;
end record;
end T;

-----------
-- t.adb --
-----------
package body T is
function Create_Object (Name : in String) return Object is
begin --------- Added
return (Name => To_Unbounded_String (Name));
end Create_Object;

function Construct return Object is
begin --------- Added
return Create_Object (Name => "Object without a name!");
end Construct;

function Name (This : in Object) return String is
begin
return To_String (This.Name);
end Name;

---------------------------------------- removed
-- ----- because it conflicts
-- ----- with t.ads version
-- type Object is tagged limited
-- record
-- Name : Unbounded_String;
-- end record;
end T;

----------------
-- test_t.ads --
----------------
with T;
use T; ------ Added
------ could of added "T." to Construct instead

procedure Test_T is
Some_Object : constant T.Object := Construct;
begin
null;
end Test_T;




In <1189015827.384331.17490@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>, =?iso-8859-2?q?Tomek_Wa=B3kuski?= <tomek.walkuski@xxxxxxxxx> writes:
Hi,

motivated by this article posted at adacore.com I have written some
code:

---------
t.ads
---------
with Ada.Strings.Unbounded;
use Ada.Strings.Unbounded;

package T is
type Object (<>) is tagged limited private;

function Create_Object (Name : in String) return Object;
function Construct return Object;
function Name (This : in Object) return String;

type Object is tagged limited
record
Name : Unbounded_String;
end record;
end T;


---------
t.adb
---------
package body T is
function Create_Object (Name : in String) return Object is
return (Name => To_Unbounded_String (Name));
end Create_Object;

function Construct return Object is
return Create_Object (Name => "Object without a name!");
end Construct;

function Name (This : in Object) return String is
begin
return To_String (This.Name);
end Name;

type Object is tagged limited
record
Name : Unbounded_String;
end record;
end T;


---------
test_t.adb
---------
with T;

procedure Test_T is
Some_Object : constant T.Object := Construct;
begin
null;
end Test_T;

------------------------------
.... and tried to compile it.

(Gentoo Linux, gnat-gpl-4.1.3.2007)

Compiler said:
"
+================GNAT BUG DETECTED==================+
| GPL 2007 (20070402-41) (i686-pc-linux-gnu) Assert_Failure namet.adb:
687 |
(...)
compilation abandoned
gnatmake: "test_t.adb" compilation error
"

Is it REALLY a compiler bug? Or am I only dumb? :) Maybe I'm doing
something, somewhere wrong?


.

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