]ANN[ Vellum 0.16: Lots Of Documentation and Watching

[Ville Vainio]

On May 6, 11:27 pm, hdante <hda... at gmail.com> wrote:

>  GPL can mix with other free software licenses, so people who write
> BSD code and do not wish to remain BSD clean are free to use GPL'd
> code. That's the important point.

No, it can't. It can only mix through aggregation, i.e. you can ship a
GPL'd "plugin" with BSD code as long as you don't import the plugin
directly.

Here's a real life example from ipython:

- Core IPython is BSD clean, and we intend to leave it that way
- If we imported a gpl'd module in some core ipython component, the
core component would be gpl (or something equally restrictive) as
well, through viral nature of the license
- Now, if you want a BSD-clean version of ipython (say, to embed it in
a commercial program - with which I have absolutely *no* problem, and
can only see good things coming from it), you would have to gleam out
all the uses of that module from the source code. Not very fun, esp.
if it's something important
- There is a GPL'd module in "extensions" folder of IPython, ipy_bzr
(that is because of bzrlib). It's never imported anywhere in ipython
source code, but the user can import it in ipy_user_conf.py. This
"contaminates" the config file and subsequently ipython (because it's
imported into python interpreter ipython is running on), but luckily
the user can opt out from importing it if he wishes to remain BSD
clean. Or he can delete the file altogether if he wishes.

Without GPL, none of this hair-splitting is necessary.

I guess I could have gone the Carl Banks route and just say "It scares
away some people". Consider my replies here an elaborate way of saying
the very same thing.