bson.md

BSON document

Methods

bson:append(key, value)

Appends a pair of key => value to bson.

local bson = mongo.BSON{}
bson:append('a', 1)
print(bson)
bson:append('b', bson)
print(bson)

Output:

{ "a" : 1 }
{ "a" : 1, "b" : { "a" : 1 } }

bson:concat(value)

Appends the contents of value (converted to a BSON document) to bson.

local bson1 = mongo.BSON{a = 1}
local bson2 = mongo.BSON{b = 2}
bson1:concat(bson2)
print(bson1)
bson1:concat(bson2)
print(bson1)

Output:

{ "a" : 1, "b" : 2 }
{ "a" : 1, "b" : 2, "b" : 2 }

bson:data()

Returns the contents of bson.

bson:find(key)

Returns the value matching key in bson or nil if nothing was found. A field name may contain dots to recurse into subdocuments.

local bson = mongo.BSON{a = {b = 1}}
print(bson:find('a'))
print(bson:find('a.b'))
print(bson:find('a.b.c'))

Output:

{ "b" : 1 }
1
nil

bson:value([handler])

Converts bson into a table and returns it. Optional handler is called for each new table (root or nested), and its return value is used instead of the original table.

When an array is restored, its length is stored in a field __array of the resulting table.

local bson = mongo.BSON{a = 1, b = {__array = true, 2, 3}}
local function sum(t)
    local r = 0
    local n = t.__array
    if n then
        for i = 1, n do
            r = r + t[i]
        end
    else
        for k, v in pairs(t) do
            r = r + v
        end
    end
    return r
end
print(type(bson:value()))
print(bson:value(sum))

Output:

table
6

Operators

tostring(bson)

Returns JSON representation of bson.

#bson

Returns the size of bson.

bson1 == bson2

Compares the contents of bson1 and bson2.