New to Universum? See the Universum (World Computer) White Paper!
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
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!
...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)
See the /universum-contracts collection.
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.
Just install the gem:
$ gem install universum
The universum scripts are dedicated to the public domain.
Use it as you please with no restrictions whatsoever.
Send them along to the wwwmake forum. Thanks!