# Application Smart Contract API

# Overview

Remove some of Lua's features, not providing IO, OS, Coroutine, Debug, package libraries.

Deos not support:

collectgarbage, dofile, getmetatable, loadfile, load, lpcall, setmetatable, xpcall.


assert, error, ipairs, next, pairs, warn, tonumber, toText, type.

Keep Lua Table and the basic grammar.

# Methods

Method Description
require_owner_auth():bool Is the account that is executing the contract the contract parent account?
exec_account():String Get the account that is running the contract.
get_balance():number Get the contract account's parent account's balance.
get_pay_fee():String,number,String Gets transaction cost information for the contract runner.
create_key(key:String):nil Create a String property named key.
set_key(key:String, value:String):nil Set the key and value of the String property.
get_key(key:String):String Returns a String property named key.
lcreate(key:String):nil Create a List property named Key.
lpush(key:String, value:String):nil Add value to the left side of the list property named Key.
rpush(key:String, value:String):nil Add value to the right side of the list property named Key.
lpop(key:String):String Deletes 1 element on the left of the list property named key, returning the deleted element.
rpop(key:String):String Deletes 1 element on the right of the list property named key, returning the deleted element.
ldel(key:String):nil Delete the list property named key.。
llen(key:String):number Returns the length of the list property named key.
lall(key:String):table Returns all elements of the list property named key.
hcreate(key:String):nil Create a hash_map property named key.
hset(key:String, field:String, value:String):nil Add key and value to the hash_map named Key: field and value,
hget(key:String, field:String):String Returns the value of field in a hash_map named key.
hlen(key:String):number Returns the size of a hash_map named key.
hdel(key:String):nil Delete the hash_map named Key.
grant(account:String, amount:number):nil The amount transferred to the account.
random_seed():number Random number under account.

# Sample of Single Chat

Both parties join the chat, then call send_chat to send the chat.

IN 	            = '1';
OUT             = '0';
MAX_NUMBER      = 256;--Maximum number of chats
MAX_CONTENT_LEN = 128;--Longest chat content
CHAT_USERS_KEY 	= 'chat_users';
CHAT_KEY 		= 'chat';
SENDER 			= 'sender';
RECEIVER 		= 'receiver';
TIMESTAMP 		= 'timestamp';
CONTENT			= 'content';
-- Initialization method
function init()
-- Add user
function add_user()
	hset(CHAT_USERS_KEY, exec_account(), IN);
-- Delete user
function del_user()
	hset(CHAT_USERS_KEY, exec_account(), OUT);
Send Chat
function send_chat(receiver, timestamp, content)
	local sender = exec_account();
	local sender_user_state = hget(CHAT_USERS_KEY, sender);
	local receiver_user_state = hget(CHAT_USERS_KEY, receiver);
	if sender_user_state ~= IN or receiver_user_state ~= IN then
		error('user first need add to chat_users');
	if #content >= MAX_CONTENT_LEN then
		error('content length must less than '.. MAX_CONTENT_LEN);
	if llen(CHAT_KEY) >= MAX_NUMBER then
    local chat_info = '{"'.. SENDER .. '":"' .. sender .. '","' .. RECEIVER .. '":"' .. receiver .. '","'.. TIMESTAMP .. '":' .. timestamp ..',"'.. CONTENT .. '":"' .. content .. '"}';
	rpush(CHAT_KEY, chat_info);