**Readline**: interactive command line
**************************************

*gnatcoll* provides an interface to the *readline* library.


License
^^^^^^^

[image: NOTE:][image] The GNU *readline* library is licensed under the
terms of the GNU General Public License, version 3. This means that if
you want to use Readline in a program that you release or distribute
to anyone, the program must be free software and have a GPL-compatible
license.

When this library is available on the system, it provides various
features to enhance command line support in tools. You also need to
pass *--enable-gpl* to configure to indicate you understand the
license of readline.

In particular, it provides various keybindings to make editing more
comfortable than Ada.Text_IO.Get_Line. For instance, it is possible to
use backspace to edit what you have just typed. It is also possible to
move forward or backward by word, go to the start or end of line,...

*readline* also provides support for completion: by using the "tab"
key, users can get all possible completions for the current word. This
behavior is controllable from Ada, where your application can provide
the list of completions.

Finally, readline comes with support for history. By using the "up"
and "down" keys, the user can navigate the commands that were
previously typed. It is also possible to preserve the history across
sessions.

See the package *GNATCOLL.Readline* for more documentation on the API.

This package is always usable, whether or not the system supports
readline. When readline is not available, the package falls back to a
*Text_IO* based implementation (still providing input, although none
of the advanced features described above will work).
