Re: C Macros and their equivalent in Ada

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 9 Wrz, 16:39, Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:

> If you need that feature, you're better off generating an Ada source
> file from the "date" utility, e.g.
>
> echo "package Compilation_Date is" > compilation_date.ads
> echo "   Timestamp : constant String := \"$(date --full-ISO)\";" >>
> compilation_date.ads
> echo "end Compilation_Date;" >> compilation_date.ads

This is a simple and valid approach but works only for things that are
build-wide.
The other extremely useful macros from the C world are __FILE__ and
__LINE__. I'm afraid there is no way to simulate them using any
external solutions, short of using the real preprocessor (why not?).

Yeah - why not use the cpp preprocessor?

Let's say that instead of implementing the .adb file we write
something that will be used to generate it:

$ cat a.adbs
with Ada.Text_IO;
procedure A is
begin
   Ada.Text_IO.Put_Line (__DATE__ & " " & __TIME__);
end A;
$ cpp -P a.adbs > a.adb
$ gnatmake a
gcc -c a.adb
gnatbind -x a.ali
gnatlink a.ali
$ ./a
Sep  9 2008 22:53:23
$

Works for me. I can even write a rule in Makefile to make (pun
intended) that automated. Not sure if GNAT project files can do it,
though.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com

Database Access Library for Ada: www.inspirel.com/soci-ada