ANN: goluago early peek preview

[Mateusz Czaplinski <czapkofan@...>]

(posted to: lua-l@lists.lua.org, golang-nuts@googlegroups.com)

Library goluago aims to become a port of Lua 5.1 interpreter to Go
Language Toolchain
(first 8c/6c/5c, ultimately maybe pure Go).

The library is at early stage of development (not feature complete/not ready
for production use), but some important "proof of concept" goals were already
completed successfully:

STATUS
------

What works:

  * from end-user perspective, following APIs were exposed and tested:
    * creating/destroying new Lua state (luaL_newstate(), lua_close())
    * basic integer operations on stack (lua_pushinteger(),
lua_gettop(), lua_equal())
    * running simple _precompiled_ Lua code chunk (luaL_loadbuffer(),
lua_call(),
      tested on precompiled chunk "return 2+3")
  * inside, minimal Lua core compiles successfully
    * compiled and tested on: x86 (8c+8g), x64 (6c+6g), Windows/Linux

Highlights on what does _not_ work yet:

  * Lua lexer/parser;
  * print/string.format, number <-> string conversions.


WANTED / PLANS
--------------

Crucial:

  * to implement (leveraging Go fmt.Sprintf) a simplified C sprintf() function,
    in extent enough to cover the handful of use cases present in Lua sources
    (this shall enable more descriptive errors from Lua internals, and make it
    possible to dump the Lua stack to screen via lua_tostring() for
easier debugging);
  * to create a utility Lua script to simplify generation of Go+C wrappers for
    Lua API functions (there are still quite many of them, and adding each one
    by hand is way too tedious);
  * for the milestones below to be doable, to fix/implement all needed
C standard
    library functions marked with FIXME (leveraging Go standard
library where possible)
    -- the embedded nyi() call shall emit a runtime panic when a function is
    called, making them easier to spot.
  * MILESTONE: get Lua lexer+parser to run (stop using noparser.c)
  * MILESTONE: get the library to pass the Lua 5.1 testsuite
    (http://lua-users.org/lists/lua-l/2006-03/msg00716.html)

Would be nice-ies:

  * write unit tests for C standard library functions implemented for Lua;
  * improve C standard library
    * maybe use some non-GPL Open Source code (FreeBSD? some stdlib
for embedded systems?);
  * extract C standard library to separate package;
  * later, "ANSI C to Go translator", in extent needed by the Lua sources?

NOTE: you're welcome to contribute anything if you fancy, and not necessarily
from this list. The points above are mostly ideas as to what I believe would be
most useful at this moment.


BACKGROUND INFO
---------------

**Lua?**

http://lua.org

Lua is a nice scripting language. Small, written in ANSI C, highly portable,
reportedly fast. Especially popular among computer games producers,
but not only.
Easily embeddable (one of its core goals), mature (Lua 1.0 ~ 1993,
many applications
worldwide since then). MIT-style licensed. Umm... oh, and I like it.


**Go Language?**

http://golang.org

Farly new language developed at Google. Authors are however experienced in
building and experimenting with programming languages (specifically C,
Limbo), with
notable uses, including OS development (Unix, Plan9/Inferno). Highly portable
(x86/x64, ARM; Linux/*nix, Windows, Mac OS X, other ports in progress), written
(bootstrapped) in C. BSD-style licensed. Popularity hard to determine
given short
time on market, but has several nice and interesting features and properties
(you can read: "I like it too").


INSTALLATION
------------

You need a recent weekly of the Go language toolkit (see:
http://weekly.golang.org).
With the environment properly set up, type:

    go get github.com/akavel/goluago/internal
    go test github.com/akavel/goluago/internal

To retrieve and run a sample program:

    go get github.com/akavel/goluago/testlua
    cd $GOROOT   # or, see $GOPATH; on Windows %GOROOT%, %GOPATH%
    bin/testlua  # on Windows: bin\testlua.exe


/Mateusz Czapliński.