Re: Pragma for conditional compilation? (Ada 2005 vs. 95)
- From: anon@xxxxxxxx (anon)
- Date: Fri, 28 Sep 2007 18:07:36 GMT
As for the "pragma Ada_05 ( name ) ;" It looks like it will not
work for your "Ada_95" user defined package and "Ada_05" Ada
defined package.
Now for conditional compilation, well I did forget to add the
sixth one. Which is the laymans answer and it always works, if you
follow the instructions.
--
-- Uncomment one and only one of the following lines:
--
-- with Package_1 ; use Package_1 ; -- Ada_95 version package
-- with Package_2 ; use Package_2 ; -- Ada_2005 version package
Now to show one example of the IF-THEN-ELSE-END concept. And it
is a lot of work if you have more than a couple of routines to
set up.
-- -------- --
-- TEST.ADB --
-- -------- --
--
-- There are a number of ways to use the "IF-THEN-ELSE-END"
-- structure, this version is one. And it does generate code
-- for the "IF-THEN-ELSE-END" statements.
--
with Test1 ;
procedure test is
--
-- True: use Alpha routines aka "user included package"
--
-- False: use Beta routine aka "system define package"
--
package IO_Package is new Test1 ( False ) ;
use IO_Package ; -- Assign default package
--
-- Use User created package
--
package Package_IO is new Test1 ( True ) ;
begin
Put_Line.all ( "This is a test" ) ;
Package_IO.Put_Line.all ( "Try this One" ) ;
end test ;
-- --------- --
-- TEST1.ADS --
-- --------- --
--
-- This Generic package defines the program global routines, the
-- redefined Ada system routines and the user created routines.
--
with Ada.Text_IO ;
generic
Configure : boolean ;
package test1 is
type Procedure_String_Type is access procedure ( item : String ) ;
-------------------------------
-- Define package procedures --
-------------------------------
Put_Line : Procedure_String_Type ;
--
-- define other declared routines/variables needed
--
private
-------------------------------
-- Emulate system procedures --
-------------------------------
procedure Alpha ( szTemp : string ) ;
-----------------------------------------------
-- Redefine/Rename system supplied procedure --
-----------------------------------------------
procedure Beta ( Item : in String ) renames Ada.Text_IO.Put_Line ;
end test1 ;
-- --------- --
-- TEST1.ADB --
-- --------- --
--
-- This Generic body package defines the user created routines and
-- this package does contain a initialize routine that configures
-- the package.
--
--
-- IF-THEN-ELSE-END -- Yes, the compiler does generate code for
-- -- this type of statament.
-- -- Also, it is easy to insert a statement in
-- -- the wrong place.
--
-- This works! Even though there is a person that says this will
-- not work.
-- If this does not you better find a different language to use.
-- Because it means the Ada "IF" statement does not work?
--
with Ada.Text_IO ;
package body test1 is
-------------------------------
-- Emulate system procedures --
-------------------------------
procedure Alpha ( szTemp : string ) is
begin
Ada.Text_IO.Put_Line ( "Alpha: " & szTemp ) ;
end ;
-----------------------
-- Initial package --
-----------------------
begin -- test1
--
-- Like I said, this is the old way of doing this by embedding
-- the configuration code in the source. But it does work.
-- Of course you could use a CASE statement instead, if you need
-- more than two options or packages set up.
--
if Configure then
Put_Line := Alpha'Access ;
else
Put_Line := Beta'Access ;
end if ;
end test1 ;
In <1190929570.915553.284000@xxxxxxxxxxxxxxxxxxxxxxxxxxx>, Jerry <lanceboyle@xxxxxxxxx> writes:
On Sep 27, 8:26 am, a...@xxxxxxxx (anon) wrote:
Thanks, anon, for the detailed answer.
The third real old way is to code in the option by a "IF-THEN-ELSE-END"
statements and use a Global constant variable(s). Its low tech but it
still works.
OK, but my "problem" is in declaring types which I want to be visible
in 95 but not visible in 05, as 05 provides them itself. An "IF-THEN-
ELSE-END" solution would have to be in the executable part of the
program (right?).
The fifth is a "NON STANDARD" way that GNAT introduce with theSame comment as above--how would this work for type declarations?
pre-release of Ada_2005 which is to use the "pragma Ada_05 ( name ) ;"
Example:
-- For GNAT you can create a routine that is define and is usable
-- only in Ada_2005 specs, by using the GNAT pragma Ada_05.
--
-- Gnat uses this concept in the Ada.Text_IO package. Just
-- search for "Ada_05" in the file "a-textio.ads". There are
-- two Get_Line functions. If the system is compiled with
-- "pragma Ada_83 ;" or "pragma Ada_95" the compile will not
-- allow a call to these routines. But under Ada_05 the routine is
-- visible.
--
-- Defined in the specification file.
procedure Routine ;
pragma Ada_05 ( Routine ) ;
--
-- Defined in the body file.
--
procedure Routine is
begin -- Routine
null ;
end Routine ;
Could I follow the type declaration with the pragma? Also, I need to
conditionally have a with clause. For example, if using Ada 2005, I
need a line like this:
with Ada.Numerics.Long_Real_Arrays;
use Ada.Numerics.Long_Real_Arrays;
(This is where the vector and matrix declarations are.)
Jerry
.
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