Linenoise
~~~~~~~~~
A minimal, zero-config, BSD licensed, readline replacement used
in Redis, MongoDB, and Android.
* Single and multi line editing mode with the usual key bindings implemented.
* History handling.
* Completion.
* About 1,100 lines of BSD license source code.
* Only uses a subset of VT100 escapes (ANSI.SYS compatible).
Can a line editing library be 20k lines of code?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Line editing with some support for history is a really
important feature for command line utilities. Instead of
retyping almost the same stuff again and again it's just much
better to hit the up arrow and edit on syntax errors, or in
order to try a slightly different command. But apparently code
dealing with terminals is some sort of Black Magic: readline is
30k lines of code, libedit 20k. Is it reasonable to link small
utilities to huge libraries just to get a minimal support for
line editing?
So what usually happens is either:
* Large programs with configure scripts disabling line editing
if readline is not present in the system, or not supporting it
at all since readline is GPL licensed and libedit (the BSD
clone) is not as known and available as readline is (Real world
example of this problem: Tclsh).
* Smaller programs not using a configure script not
supporting line editing at all (A problem we had with Redis-cli
for instance).
The result is a pollution of binaries without line editing support.
So I spent more or less two hours doing a reality check
resulting in this little library: is it *really* needed for a
line editing library to be 20k lines of code? Apparently not,
it is possibe to get a very small, zero configuration, trivial
to embed library, that solves the problem. Smaller programs
will just include this, supporing line editing out of the box.
Larger programs may use this little library or just checking
with configure if readline/libedit is available and resorting
to linenoise if not.
Terminals, in 2010
~~~~~~~~~~~~~~~~~~
Apparently almost every terminal you can happen to use today
has some kind of support for basic VT100 escape sequences. So I
tried to write a lib using just very basic VT100 features. The
resulting library appears to work everywhere I tried to use it,
and now can work even on ANSI.SYS compatible terminals, since
no VT220 specific sequences are used anymore.
The library is currently about 1100 lines of code. In order to
use it in your project just look at the *example.c* file in the
source distribution, it is trivial. Linenoise is BSD code, so
you can use both in free software and commercial software.
Tested with...
~~~~~~~~~~~~~~
* Linux text only console ($TERM = linux)
* Linux KDE terminal application ($TERM = xterm)
* Linux xterm ($TERM = xterm)
* Linux Buildroot ($TERM = vt100)
* Mac OS X iTerm ($TERM = xterm)
* Mac OS X default Terminal.app ($TERM = xterm)
* OpenBSD 4.5 through an OSX Terminal.app ($TERM = screen)
* IBM AIX 6.1
* FreeBSD xterm ($TERM = xterm)
* ANSI.SYS
* Emacs comint mode ($TERM = dumb)
Please test it everywhere you can and report back!
Let's push this forward!
~~~~~~~~~~~~~~~~~~~~~~~~
Patches should be provided in the respect of linenoise
sensibility for small easy to understand code.
Send feedbacks to antirez at gmail
e8cb02f3f7