Re: how to organize source code for a complete software? Thanks!

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Welcome Jinsong :-)

Le Sun, 09 Oct 2011 18:20:53 +0200, Jinsong Zhao <jszhao@yeah.net> a écrit:
> When I using Ada, I don't know how to do. There are procedure, function,  
> package, package body, and so on (with different file extension, e.g.,  
> ada, adb, ads, ...). And there is no main program.
*.ada is not that common. Where did you see it ? *.adb and *.ads are not  
Ada specific, these are GNAT specific instead. The Ada Reference Manual  
does not specify file layout, nor file extensions.

So this all depend on your compiler, which is GNAT here it seems (you may  
also have a look at Janus Ada from RRSoftware, if Ada 95 is enough for  
you).

The file layout for GNAT is as this:
    Package specification in *.ads files
    Package body in *.adb
    Main procedure in *.adb
    Separate body in *.adb

In few words: specifications goes to *.ads, which stands for Ada  
Specification, and implementations goes to *.adb, which stands for Ada  
Body.

File names (not extensions) must be derived from compilation unit names,  
with this transformation applied: all uppercase characters turned into  
lowercase and periods turned into dashes.

Example: your have a package name My_AI_Lib.Knowledge (to say we play with  
fun things). Then the specification will be in my_ai_lib-knowledge.ads,  
the body will be in my_ai_lib-knowledge.adb. If your test main program is  
a procedure named Test_My_AI, then it will belong to a file named  
test_my_ai.adb

Similar things applies with separate bodies and child packages.

Worth to read at your stage:
http://www.adacore.com/wp-content/files/auto_update/gnat-unw-docs/html/gnat_ugn_2.html

> Would anyone here like to give a an analogy between the source code  
> organization in Fortran and the one in Ada?
Unless you use separate bodies all over the place, there is no way to  
compare Ada layout and Fortran layout. With Ada, multiple procedure may  
belong to a single package. May be there exist some compiler which  
requires each procedure to reside in its own file, but GNAT don't use such  
a layout. Keep in mind this is compiler specific!

> And, please, if you like, point me a small, complete open source  
> software in Ada (not a library or package). I should be compiled and  
> run. I just hope to learn how to start a software in Ada by example.
I did not checked all of it, but here is a good list of samples (there may  
be some others too):
http://sandbox.mc.edu/~bennet/ada/examples/

> Any suggestions or comments will be really appreciated. Thanks in  
> advance.
Yes, start with this:

>>>
-- Hello World, the quick easy form.

with Ada.Text_IO; use Ada.Text_IO;

procedure Hello is
begin
    Put_Line ("Hello, Bonjour, Ohayo");
end;
>>>

Second alternative, for people who enjoy to be more formal or strict:

>>>
-- Hello World, the proud form (lol).

with Ada.Text_IO;

procedure Hello is
    package IO renames Ada.Text_IO;
    Greeting_Message : constant String := "Hello, Bonjour, Ohayo";
begin
    IO.Put_Line (Greeting_Message);
end Hello;
>>>

> Regards,
> Jinsong
Have a nice time Jinsong


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