Re: [Caml-list] Caml toplevel and readline

[Jacques Garrigue <garrigue@kurims.kyoto-u.ac.jp>]

From: John Max Skaller <skaller@ozemail.com.au>
> Jacques Garrigue wrote:
> 
> > As long as you distribute the special runtime containing readline
> > separately from the toplevel, this reasoning is OK. 
> 
> 	Hang on! I already have libreadline.
> I don't want INRIA to distribute it, just detect if I already
> have it. If I do, I would like to be able to link it in
> to the top level.

With the FSF definition of linking, linking with a dll is exactly the
same as including the object code. Otherwise the GPL would be nothing
more than the LGPL.

Here is the relevant quote from the GPL FAQ:

Q. If a library is released under the GPL (not the LGPL), does that mean
that any program which uses it has to be under the GPL?

A. Yes, because the program as it is actually run includes the library. 

> 	Alternatively, why not build the toplevel
> with ledit?

I suppose that most people at INRIA are already using it with ledit,
so they didn't think of including it. Also, ledit requires libunix,
but I don't know if the terminal capacities included in ocamlrun
would be enough in this case. The way it works currently, you probably
need pipes. But all this should be solvable.

> > But the first man making a custom toplevel is dead: 
> > having both in the same file won't do.
> 
> 	I am the one linking it into the toplevel, not INRIA.
> It will have no impact on me, since I do not use the top
> level for producing code (only for testing the occasional
> small fragments).

The standard distribution already contains a labltk toplevel, linked
in custom mode. And INRIA distributes binaries.

> 	It's doubtful if the FSF licences mean much
> anyhow. Python uses readline by default in its top level,
> if available. There are lots of Python programs out there,
> being run with a binary with readline linked in, which
> are not licenced GPL, Python itself being an example.

As was pointed out recently, Python has just switched to GPL.
I don't know whether this is related to readline, but clearly if you
start using GPL'd libraries, you should expect a strong pressure for
making everything GPL'd.
As section 5 of the GPL states, you do not have to accept the license.
But if you do not accept it you shouldn't use the code. I think this
is clear enough in spirit, and I see nothing wrong in that.

Cheers,

Jacques Garrigue
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