iLiad Lua: scripting for Iliad

[hansel]

Hi All,

Lua is a scripting language. And it's running on my Iliad right now! It's easy to learn (if you are used to programing), its interpreted (you don't have to compile anything), it's fast and small (the executable is 128K). Much smaller than perl, python or ruby; much easier and fun than shell scripts, awk, sed...

Lua is even cooler than it looks at first glance: it's easy to extend it (write functions in C, and call them from lua), or embed a lua interpreter in a C-program (it's used for scripting in game engines, camera's, ...)

The attached file contains the Lua binary with extensions for network stuff (luasocket) and XML parsing (luaexpat). This is enough to fetch files from Internet (ftp, http) and parse rss feeds. Unpacked it's less than 400K.

Is this cool or is it not? I can feel the karma

If you are interested to compile this stuff yourself: I keep notes on http://wiki.hpelbers.org/Other_stuff_for_the_Iliad. It's not complete or well maintained, but it might save some time...

Lua can be installed on your Iliad as follows:

tar xvfz lua_for_iliad.tar.gz
cd lua_for_iliad
cp -r * /usr/local

The executable will be in /usr/local/bin, which is included in PATH by default.

Happy scripting
Hansel

Links:

• Programming Lua (5.0) (very good an readable)
• Reference manual
• http://www.lua.org/about.html
• http://www.keplerproject.org/luaexpat/
• http://www.tecgraf.puc-rio.br/~diego...nal/luasocket/
  

PS: No warranty what so ever
PS2: I'm just playing with this: not going to maintain or document it

[ericshliao]

The Lua website declares that it's some script for game (if I read it correctly). Do we have some example to run on iLiad?

[hansel]

Hi ericshliao,

Originally Posted by ericshliao

The Lua website declares that it's some script for game (if I read it correctly). Do we have some example to run on iLiad?

No useful examples yet... But I was able to fetch a web page and read the Iliad networkprofiles (XML) with just a few lines of code...

Lua is not only for games: it's a full blown general purpose language.
You can do anything you want with files, numbers, regular expressions, sockets, whatever. It's used in games because it's small, fast, and easy to embed. String handling is much easier than in C. You don't have to compile: you can test on your PC, and run on your Iliad by just copying the file. Plus it can do what you normally do with shell scripts...

I'm still learning Lua (used to C, C++ and Ruby), but I like what I see!
Here's a small example with file io and (cryptic ) string stuff: you can save it as hexdump.lua

local index = 0       -- offset in file
local block = 16      -- bytes on a line

-- process file if given, else read from stdin
if arg[1] then
  io.input(arg[1])
end

while true do
  local bytes = io.read(block)
  if not bytes then break end
  io.write(string.format("%04X:  ", index))               -- byte counter
  for b in string.gfind(bytes, ".") do
    io.write(string.format("%02X ", string.byte(b)))    -- hex values
  end
  io.write(string.rep("   ", block - string.len(bytes) + 1))
  io.write(string.gsub(bytes, "%c", "."), "\n")            -- ascii values
  index = index+block
end

You can call is as:

echo "hello" | lua hexdump.lua   # read from standard input
lua hexdump.lua /etc/passwd         # read a file and dump it
lua hexdump.lua </etc/passwd       # use file content as input

Google around a bit and be happy ;-)

[Lemming]

This is really cool - Lua is a really interesting language, definitely not just for games. It seems like it would be a good fit for writing Iliad apps, for sure - lightweight, extensible, fast. Adobe Lightroom is about 70% Lua.

Cheers,
Colin