modules and mains

[Brian Tiffin]

On Sunday, 22 August 2021 at 03:22:02 UTC, Brian Tiffin wrote:
> Is this wrong thinking?  I'm ~~working on~~ playing with a 
> first project.
>
> Meant to be a suite of tools, each usable from the command 
> line, i.e. with a `main`.  Then a manager program that accepts 
> subcommands for dispatch *and other boss type things*.
>
> boss.d wants to import command1.d command2.d etc.
>
> Is there a way for `command1.d` to know it's an `import` versus 
> a file named as part of a `gdc` compile?
>
> I'd like to skip defining `main` during `import` (using a 
> different name for boss dispatch), but do define `main` when 
> it's a standalone compile.  Or is that a bad way of thinking 
> about D program development interactions?
>
> Cheers

Tried this:

```d
prompt$ cat A.d
module A;
version (boss) {} else {
    int main(string[] args) {
        return command(args);
    }
}

int command(string[] args) {
    import std.stdio: writeln;
    writeln(args);
    return 0;
}
```
with

```d
prompt$ cat B.d
module B;
version = boss;

import A;

int main(string[] args) {
    A.command(["Boss calling A"]);
    return 0;
}
```

But I'm getting a link error from gdc

```
prompt$ gdc -o B B.d
/tmp/ccWg1BrF.o: In function `_Dmain':
B.d:(.text+0x52): undefined reference to `_D1A7commandFAAyaZi'
collect2: error: ld returned 1 exit status
```

Is it just wrong thinking and *try again, ya noob*?   ;-)

Cheers again