BSON generator/parser in pure Lua (5.1)

Introduction

This is a very simple BSON implementation in Lua. It doesn't support all BSON types (yet). In particular, and ironically, it doesn't support the floating point type.

Building

There are no external dependencies, Lua 5.1 or LuaJIT should work.

Supported Types

int32, int64
boolean
string
number
array
document
binary (generic)
UTC datetime

Limitations

Pure Lua has no way of retrieving millisecond system time, so right now I hack "seconds * 1000" for BSON datetime.
No support for floating point (double) until I figure out how to encode/decode it in pure Lua.
int64 is limited by Lua's double type.
No javascript-ish types (code, object_id, etc)

Getting started

Here is an example to get you started:

bson=require'bson'
epoch=os.time({year=1970, month=1, day=1, hour=0})
bsondoc1=bson.encode{username="maroc", 
		     info={first="todd",
			     last="coram",
			     age=46,
			     signature1=bson.binary("\000\001\002\003",bson.B_GENERIC),
			     signature2=bson.binary("\000\001\002\003"),
			     saved=true,
			     now=bson.utc_datetime(),
			     past=bson.utc_datetime(epoch * 1000),
			     colors={"Red","Green","Blue"}
		     }}
decoded=bson.decode(bsondoc1)

print("username = "..decoded.username)

for i,v in pairs(decoded) do print(i,v) end
print()
for i,v in pairs(decoded.info) do print(i,v) end
print()
for i,v in ipairs(decoded.info.colors) do print(i,v) end