New to Universum? See the Universum (World Computer) White Paper!
Universum (Ruby Edition)
next generation ethereum 2.0 world computer runtime - run contract scripts / transactions in plain vanilla / standard ruby on the blockchain - update the (contract-protected / isolated) world states with plain vanilla / standard SQL
- home :: github.com/s6ruby/universum
- bugs :: github.com/s6ruby/universum/issues
- gem :: rubygems.org/gems/universum
- rdoc :: rubydoc.info/gems/universum
Usage
The Greeter - Your Digital Pal Who's Fun to Be With
Let's use the "Create a digital greeter" starter example from Ethereum to compare contracts in Solidity with contracts in Ruby:
pragma solidity >=0.4.22 <0.6.0;
contract Mortal {
/* Define variable owner of the type address */
address owner;
/* This constructor is executed at initialization and sets the owner of the contract */
constructor() public { owner = msg.sender; }
/* Function to recover the funds on the contract */
function kill() public { if (msg.sender == owner) selfdestruct(msg.sender); }
}
contract Greeter is Mortal {
/* Define variable greeting of the type string */
string greeting;
/* This runs when the contract is executed */
constructor(string memory _greeting) public {
greeting = _greeting;
}
/* Main function */
function greet() public view returns (string memory) {
return greeting;
}
}and
##################
# Greeter Contract
def setup( greeting )
@owner = msg.sender
@greeting = greeting
end
def greet
@greeting
end
def kill
selfdestruct( msg.sender ) if msg.sender == @owner
end(Source: contracts/greeter.rb)
And let's run the greeter with Universum (Uni):
require 'universum'
## create contract (english version)
tx = Uni.send_transaction( from: '0x1111', data: ['./greeter', 'Hello World!'] )
greeter = tx.receipt.contract
puts greeter.greet
#=> Hello World!
## create contract (spanish version)
tx = Uni.send_transaction( from: '0x1111', data: ['./greeter', '¡Hola, mundo!'] )
greeter_es = Receipt[ tx ].contract
puts greeter_es.greet
#=> ¡Hola, mundo!
puts greeter.greet
#=> Hello World!
puts greeter_es.greet
#=> ¡Hola, mundo!
...The Coin - Minimum Viable Token
What's next? Let's use the "Create your own crypto-currency" example from Ethereum to compare contracts in Solidity with contracts in Ruby again:
pragma solidity >=0.4.22 <0.6.0;
contract MyToken {
/* This creates an array with all balances */
mapping (address => uint256) public balanceOf;
/* Initializes contract with initial supply tokens to the creator of the contract */
constructor(
uint256 initialSupply
) public {
balanceOf[msg.sender] = initialSupply; // Give the creator all initial tokens
}
/* Send coins */
function transfer(address _to, uint256 _value) public returns (bool success) {
require(balanceOf[msg.sender] >= _value); // Check if the sender has enough
require(balanceOf[_to] + _value >= balanceOf[_to]); // Check for overflows
balanceOf[msg.sender] -= _value; // Subtract from the sender
balanceOf[_to] += _value; // Add the same to the recipient
return true;
}
}and
############################
## My Token Contract
def setup( initial_supply )
@balance_of = Mapping.of( Address => Money )
@balance_of[ msg.sender] = initial_supply
end
def transfer( to, value )
assert @balance_of[ msg.sender ] >= value
assert @balance_of[ to ] + value >= @balance_of[ to ]
@balance_of[ msg.sender ] -= value
@balance_of[ to ] += value
true
end(Source: contracts/mytoken.rb)
More Contract Samples
See the /universum-contracts collection.
More Documentation / Articles / Contracts
Programming Crypto Blockchain Contracts Step-by-Step Book / Guide - Let's start with ponzi & pyramid schemes. Run your own lotteries, gambling casinos and more on the blockchain world computer...
Safe Data Structures (Array, Hash, Struct) - Say goodbye to null / nil (and maybe) and the Billion-Dollar mistake. Say hello to zero and the Billon-Dollar fix.
Install
Just install the gem:
$ gem install universum
License
The universum scripts are dedicated to the public domain.
Use it as you please with no restrictions whatsoever.
Questions? Comments?
Send them along to the wwwmake forum. Thanks!
