Re-using copyrighted code

[Benjamin Kaplan]

On Sat, Jun 8, 2013 at 2:31 PM, Malte Forkel <malte.forkel at berlin.de> wrote:
> Hello,
>
> I have written a small utility to locate errors in regular expressions
> that I want to upload to PyPI.  Before I do that, I would like to learn
> a litte more about the legal aspects of open-source software. What would
> be a good introductory reading?
>
> Plus, I have one very specific question: In my package, I use modified
> code from sre_parse.py, which is part of the Python release. That file
> has the following header:
>
> #
> # Secret Labs' Regular Expression Engine
> #
> # convert re-style regular expression to sre pattern
> #
> # Copyright (c) 1998-2001 by Secret Labs AB.  All rights reserved.
> #
> # See the sre.py file for information on usage and redistribution.
> #
>
> The referenced information is missing in the version of sre.py that
> comes with current versions of Python, but I found it in the archive
> http://effbot.org/media/downloads/sre-2.2.1.zip. It reads:
>
> #
> # Secret Labs' Regular Expression Engine
> #
> # re-compatible interface for the sre matching engine
> #
> # Copyright (c) 1998-2001 by Secret Labs AB.  All rights reserved.
> #
> # This version of the SRE library can be redistributed under CNRI's
> # Python 1.6 license.  For any other use, please contact Secret Labs
> # AB (info at pythonware.com).
> #
> # Portions of this engine have been developed in cooperation with
> # CNRI.  Hewlett-Packard provided funding for 1.6 integration and
> # other compatibility work.
> #
>
> Now, how am I supposed to deal with that? Ask Secret Labs for some kind
> of permission? Leave it as it is and add my own copyright line?
>
> Malte
>

You can find the license terms for all versions of Python at
http://docs.python.org/3/license.html
I'm not a lawyer, but it looks like you just need to include the
copyright statement.

I'm not sure why the sre stuff is still licensed under the 1.6
license. Did no one get permission to distribute it under the PSF
license, or did no one bother to rewrite the comment in the file?