== json.lua ==

Simply copied from [http://json.luaforge.net/ JSON4Lua].  This is only the JSON encoding/decoding part, the JSON-RPC client depend on the (missing) !LuaSocket HTTP module.

'''`string json.encode( lua_object )`'''[[BR]]
Returns the Lua object JSON encoded into a string.
Example:
{{{
json = require("json")
print (json.encode( { 1, 2, 'fred', {first='mars',second='venus',third='earth'} } ))
}}}
prints
{{{

[1,2,"fred", {"first":"mars","second":"venus","third","earth"}]
}}}

'''`lua_object json.decode( json_string )`'''[[BR]]
Decodes the JSON encoded data structure, and returns a Lua object with the appropriate data.
Example:
{{{
json = require("json")
testString = [[ { "one":1 , "two":2, "primes":[2,3,5,7] } ]]
o = json.decode(testString)
for k,v in pairs (o) do
    print (k,v)
end
print ("Primes are:")
for i,v in ipairs (o.primes) do
    print (i,v)
end
}}}
prints:
{{{
one		1
two		2
primes		table: 0032B928
Primes are:
1		2
2		3
3		5
4		7
}}}

'''`json.null`'''[[BR]]
A unique value that will be encoded as a null in a JSON encoding.

This is necessary in one situation. In Lua, if a key in a table has a `nil` value, the key is simply discarded (since any non-existent key has a `nil` value). The encoding of arrays has been built to manage this `nil`-values in arrays, but associative arrays provide a problem. Consider:
{{{
t = { user="test", password=nil }
}}}
Since Lua simply discards the password key, JSON4Lua encodes this as the JSON string
{{{
{"user":"test"}
}}}
If, for some reason, your JSON RPC Server requires a defined `null` value, use the following code:
{{{
t = { user="test", password=json.null }
}}}
This will now correctly encode to:
{{{
{"user":"test","password":null}
}}}
Incidentally, `json.null` is simply a function that returns itself, so that you can use either `json.null` or `json.null()` as you fancy.

'''Note''': A JSON `null` value is decoded as Lua `nil`, not as `json.null`.