Hi,
I'm currently implementing a data type which is quite similar to complex numbers.
Because of the similarity, I could copy paste (with minor modifications) the toString methods and the helper functions from std.complex. The much bigger rest of it is my own work.
I would like to publish this under Boost License 1.0.

Do i have to list the authors of std.complex as authors of the module?
Or should i list the authors in the commentary above the copied functions?

What happens to copyright?
Can I publish it under "Copyright 2019, My Name" or do i have to use the copyright from std.complex?

I'm not a lawyer and i don't like to deal with this kind of stuff.
I just want that people are able to use it without implications

On Saturday, 16 November 2019 at 09:21:41 UTC, René Heldmaier wrote:
> Do i have to list the authors of std.complex as authors of the module?
> Or should i list the authors in the commentary above the copied functions?

I believe the correct answer would depend on your jurisdiction (the country you live in), so there is no correct answer in an international news group.

The license says that you have to retain all copyright notices. So you have to retain them as they are written in the source code and in the license text. That is the conservative interpretation.

However you can have your own license at the top and append all the other licenses below it.

So you can use a different license for the code you added.


> What happens to copyright?
> Can I publish it under "Copyright 2019, My Name" or do i have to use the copyright from std.complex?

It is a derived work so the copyright is shared. However, you hold copyright even if you don't state it (in most jurisdictions). There are international agreements that ensure this and many countries have joined (but not all). The statement "Copyright 2019, My Name" is incomplete though. It would be better to state "Copyright 2019, My Name and others (see individual files)".

What you state would depend on what is substantial.

The license states that you can publish executables without mentioning the original authors, however, check the practice in the jurisdiction you live in. I believe some jurisdictions do not allow you to sign away authorship rights and what that implies might vary.

There might be other requirements in your country than what is stated in the license.


> I just want that people are able to use it without implications

Well, the implications are in the laws of the country you live in… primarily. What is considered fair might vary. What is considered substantial might vary.  What is considered a derived work might vary.

Just follow the license to the letter… Copy in the code you build on and modify it in place. You ought to be able to add your own code above or below it, just mark the boundaries with comments. You can also modify the code of course, then just add your name to the list of authors.

As a matter of courtesy I would have added a notice on the top of the file that says that function x, y, z was lifted from such and such library with a "see comments for details" notice.

On Saturday, 16 November 2019 at 10:02:58 UTC, Ola Fosheim Grøstad wrote:
> On Saturday, 16 November 2019 at 09:21:41 UTC, René Heldmaier wrote:

Thanks a lot for the lengthy reply ;). I live in Germany by the way...

> statement "Copyright 2019, My Name" is incomplete though. It would be better to state "Copyright 2019, My Name and others (see individual files)".

I'll do that. Should i do it the same way for authors on module level? e.g
Authors: René Heldmaier and others (see individual files)

> Just follow the license to the letter… Copy in the code you build on and modify it in place. You ought to be able to add your own code above or below it, just mark the boundaries with comments. You can also modify the code of course, then just add your name to the list of authors.

My plan is now to put this comment above each copied function:

/* The following function is derived from phobos std.complex https://github.com/dlang/phobos/blob/master/std/complex.d
   Authors:     Lars Tandle Kyllingstad, Don Clugston
   Copyright:   Copyright (c) 2010, Lars T. Kyllingstad.
   License:     $(HTTP boost.org/LICENSE_1_0.txt, Boost License 1.0)
   Modified by: René Heldmaier
*/

You think that's ok?

On Saturday, 16 November 2019 at 10:02:58 UTC, Ola Fosheim Grøstad wrote:

> As a matter of courtesy I would have added a notice on the top of the file that says that function x, y, z was lifted from such and such library with a "see comments for details" notice.

I will add this comment at the top the file also:

/* The functions

   auto dual(R)(const R re),
   auto dual(R, D)(const R re, const D du),
   string toString() const,
   void toString(Writer, Char)(scope Writer w, scope const ref FormatSpec!Char formatSpec) const

   and the corresponding unittests are derived from phobos std.complex
   (github.com/dlang/phobos/blob/master/std/complex.d).
   See comments for more details
*/

Anyone who thinks i go to jail for this, please tell me now ;)