Re: gnatmake error I don't understand

[Robert A Duff <bobduff@shell01.TheWorld.com>]

drrob106@gmail.com writes:

> I was able to get this code to link by adding a separate procedure,
> testhabits.adb that merely called Habits from texthabits.

Right.  To be portable, your 'main' must be a parameterless library
procedure (not nested in a package).

> I was not aware that libraries listed in 'with' clause in a spec file
> do not need to be repeated in the body file.  I'll play with that a
> little.  I never coded this way in M-2, and I don't think that M-2
> would have allowed that.

Are you sure?  It's been a long time since I used Modula-2, but
I seem to recall it behaved like Ada in this regard.

Enable warnings!  Otherwise, you will accumulate useless "with"
clauses as you modify your code (among other problems).

> How would I write the gpr file if I were to try to have the main
> program in the package, as I've tried to do here?

GNAT does not support that.  I don't think any Ada compilers support
that.

> It is my understanding that C-flavored languages do this routinely.

Well, C doesn't have packages.  The closest thing is "translation
unit", which is basically a .c source file, and you're right that
it can contain the "main" along with other stuff.

I think this area of Ada is slightly flawed.

> At least, from what I've seen in books and articles.

- Bob