[eyedb-devel] Using readline() in OQL

[François D. <fra...@de...>]

Hi,

I've changed the OQL monitor in order to use the readline library. This
library allows command line editing with history and is used by many
free software, in particular MySQL or PostgreSQL.

However, using this library raises a licensing issue that I'd like to
discuss here.

There are 2 implementations of the readline library:
- the original GNU readline, licensed under the GPL
- the editline library, licensed under BSD license

Using the GNU readline library requires to license the derived work
(here, the OQL monitor, at least) under the GPL. 

OTOH, using the BSD editline library does not require any change in the
licensing of the OQL monitor (which is currently under the LGPL).

Here are the possible choices:
- change the license of the OQL monitor to place it under the GPL and
use the GNU readline
or
- keep the same license and use the BSD editline
or
- keep the same license and allow at configure time choice between the
GNU readline and the BSD editline, but issue a warning if the GNU
readline library is selected

The current solution (in subversion) is the third, but without a
warning.

You can test it by:
- installing libedit on your machine
- or installing readline and configure with:
configure --with-readline=readline

A question: does anybody know if it is allowed to have a "derived work"
of a GPL software be licensed under the LGPL? My guess is no, but I'd
like to be sure.

François