Bsontypes

LuaMongo automatically marshals data between Lua types and BSON types. Here is the mapping:

Lua Type	BSON Type	Notes
nil	Null	value
boolean	Boolean
number	Floating point
string	String
table	new BSON Document by iterating pairs
mongo.Date	UTC Datetime	milliseconds since epoch, 64-bit, precision lost
mongo.Timestamp	Timestamp	special mongodb type, 64-bit, precision lost
mongo.RegEx	Regular Expression
mongo.NumberInt	32-bit integer
mongo.NumberLong	64-bit integer	precision lost
mongo.Symbol	Symbol
mongo.ObjectId	ObjectID	MongoDB document ID
thread	UNSUPPORTED
function	UNSUPPORTED
userdata	UNSUPPORTED

###How To Use BSON Types You use the non-native types as follows:

store 'foo' as an integer, and 'bar' as a float

db:insert('test.values', { foo = mongo.NumberInt(5), bar = 5 }

###64-bit Integer Precision Warning

Many BSON types are natively 64-bit integers. However, Lua numbers only support 52-bits of integer precision. Thus, if you convert these BSON types into Lua, you may lose precision.

###Implementation Notes

The various BSON type objects (e.g. mongo.Date) work by creating a table with the following structure:

t[1] = value

getmetatable(t).__bsontype = numeric_code_of_bson_type

When the marshalling code sees a table with this metatable field, it will change how it marshals the object. You can find this in utils.cpp [90].