Quick and dirty libreadline binding with completion support

[Dmitriy Kryuk <kryukdmitriy@...>]

I have written a quick and dirty Lua binding for libreadline with 
limited line completion support. It's provided as a FreeBSD port, but it 
should be easy to figure out how to build it as a standalone library.

Download at: http://rghost.ru/7wZ2xgrbT
Mirror: ftp://motoprogger.ru/distrib/lua/readline/lua-readline.tar.xz

It provides two ways of completion management:
1) A table of strings
2) A generator function
A table of strings is considered unsorted and is searched for strings 
beginning with the already typed-in prefix. A generator function gets 
the typed-in prefix and must return an iterator of matching strings. The 
strings are displayed in the iterator order and are not obligated to 
begin with the provided prefix.

It's called like:

local readline = require "readline"
result = readline.readline("Prompt: ", {"Completion1", "Completion2", 
"Other completions"})
-- or
result = readline.readline("Prompt: ", generator_function)

The generator function can be like:

function generator(prefix)
     local suffixes = {"a", "e", "i", "o", "u", "y"}
     local i = 0
     return function()
         i = i + 1
         return prefix..suffixes[i]
     end
end

The library's current limitations are:
1) It doesn't save or restore libreadline state. In particular it 
interferes with the interactive Lua shell.
2) It doesn't support libreadline key binding or functions
3) It supports only one completion generator or array and allows to type 
in more than one word of the same set.
Probably I shall provide some usage examples in a while. I would be glad 
to see it converted to a more appropriate distribution form, provided 
with documentation and developed further.