Re: Revised LaTeX Project Public License (LPPL)

[Walter Landry <wlandry@ucsd.edu>]

Frank Mittelbach <frank.mittelbach@latex-project.org> wrote:
> Walter Landry writes:
>  > So if the LaTeX
>  > people become evil and later decide to change the format so that you
>  > get different behavior with non-validating files, then there has been
>  > a retroactive change in the licensing terms.  What exactly the format
>  > is needs to be nailed down.
> 
> good point. not in the license terms but in the result -- bad
> 
> but again something along the lines of 
> 
>  1. You must make your modified package output to the screen a message
>     that it isn't the original package
>  
>  2. If the environment where your modified package is intended to be
>     used provides a documented standard way of emitting such messages
>     without making any other processing changes, you must use that.
> 
> would take care of that, or not? (2) would apply only if not evil and if we
> turn evil you only have to do (1)

I think I understand what you're trying to say, but I'm not sure.
You're saying you must either

  1) notify the user

or

  2) use the standard method if it doesn't change anything


That would mostly cover it, but I don't think that you're actually
happy with it.  Consider this: I make a fork of LaTeX called FubarTeX.
The main feature of this reimplentation is that it aborts if it sees
any attempts to notify by individual files.  Now I can (indeed must)
modify all of my LaTeX files to not do any notification.  Since
they're all "intended" to be run with FubarTeX, I'm free to distribute
these modified LaTeX files.

Actually, since LaTeX can be manipulated from the inside, it seems
like it wouldn't even be hard to modify standard LaTeX to do this.
All that you really need to do is redefine the notification macros to
abort or do nothing.  I could then distribute this redefinition along
with my modifications, with the note that they should be used
together.

The basic problem is that the individual files are not the whole
program.  Trying to specify what is the "intended" interpreter leads
to non-free conditions.

Regards,
Walter Landry
wlandry@ucsd.edu