• KytoDragon (36/36) Apr 11 2022 I am currently maintaining a port of a c++ library that uses
• wjoe (3/9) Apr 11 2022 No, version identifiers don't escape module scope.
• =?UTF-8?Q?Ali_=c3=87ehreli?= (10/12) Apr 12 2022 Have you tried mixing in the versions? Have one file with the versions
• H. S. Teoh (21/38) Apr 12 2022 [...]
• cc (4/12) Apr 17 2022 Another option for this was suggested here:

KytoDragon <kytodragon e.mail.de> writes:

I am currently maintaining a port of a c++ library that uses 
conditional compilation to integrate into the users program. e.g.:

config.h (edited by the user of the library)
```
#define USE_MY_ASSERT
void MY_ASSERT(bool expr) {...}
```

library.c
```
include "config.h"
#ifndef USE_MY_ASSERT
     void MY_ASSERT(bool expr) {...} // default implementation
#end
```

Given that static if at top-level has been broken for some time 
(https://issues.dlang.org/show_bug.cgi?id=17883, 
https://issues.dlang.org/show_bug.cgi?id=20905, 
https://issues.dlang.org/show_bug.cgi?id=21171), I tried to use 
version identifiers for this in D:

config.d
```
version = USE_MY_ASSERT;
void MY_ASSERT(bool expr) {...}
```

library.d
```
import config;
version (USE_MY_ASSERT) {} else {
     void MY_ASSERT(bool expr) {...}
}
```

Sadly this results in an identifier conflict, as the version set 
in config.d does not seem to affect library.d. Is there any way 
to import version specifiers from a separate file? I don't want 
to pollute the users build files (dub.json etc.) with dozens of 
versions they need to pass to the compiler.

wjoe <invalid example.com> writes:

On Monday, 11 April 2022 at 08:57:12 UTC, KytoDragon wrote:
 [...]
 Sadly this results in an identifier conflict, as the version 
 set in config.d does not seem to affect library.d. Is there any 
 way to import version specifiers from a separate file? I don't 
 want to pollute the users build files (dub.json etc.) with 
 dozens of versions they need to pass to the compiler.

No, version identifiers don't escape module scope.
See 24.1.4 https://dlang.org/spec/version.html for reference.

=?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:

On 4/11/22 01:57, KytoDragon wrote:

 Is there any way to import
 version specifiers from a separate file?

Have you tried mixing in the versions? Have one file with the versions 
in it:

   // file: 'versions'
   version = x;

Then mix it in:

   mixin (import ("versions"));

   version (x) { /* ... */ }

Seems to work for me.

Ali

"H. S. Teoh" <hsteoh quickfur.ath.cx> writes:

On Tue, Apr 12, 2022 at 10:07:15AM -0700, Ali Çehreli via Digitalmars-d-learn
wrote:
 On 4/11/22 01:57, KytoDragon wrote:
 
 Is there any way to import version specifiers from a separate file?

 
 Have you tried mixing in the versions? Have one file with the versions
 in it:
 
   // file: 'versions'
   version = x;
 
 Then mix it in:
 
   mixin (import ("versions"));
 
   version (x) { /* ... */ }
 
 Seems to work for me.

[...]

If you need globally-defined versions, I'd just use the command-line
option `-version=MyVersionA -version=MyVersionB ...`.

Or, if you absolutely have to define versions in a source file, why not
just use enums + static if instead:

	// versions.d
	module versions;
	enum MyVersionA = true;
	enum MyVersionB = true;

	// program.d
	import versions;
	static if (MyVersionA) {
		...
	} else {
		...
	}

	// ... and so on


T

-- 
An elephant: A mouse built to government specifications. -- Robert Heinlein

cc <cc nevernet.com> writes:

Another option for this was suggested here:

https://forum.dlang.org/post/qbvgboihhwcuqglygzec forum.dlang.org

On Wednesday, 12 February 2020 at 09:28:15 UTC, Simen Kjærås 
wrote:
 So, you could have a file called 'versions' containing this:


 -version=Compress




 and feed it to dmd like so:

     dmd -w -wi -g  versions -main foo.d