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Ethereum - Coggle Diagram

- - - - No error thrown when accessing
    - - Balance property
      - address.transfer(10) and send()
    - - Unlimited length is expensive
    - - key-value
      - doesn't support iteration
    - - struct Funder { address addr; uint amount; }
      - mapping(address => Funder) myFunder;
  - - - is concurrent
      - mining needs to happen
      - consensus has to be reached
      - doesn't return a value
      - events used to react to this
      - The value is the transaction hash
      - every node will have to do that
    - - Just like a query call
    - - For the middle layer
  - - - if it's consumed by the same application that better use returns
    - - unnamed
      - cannot have arguments
      - cannot return values but raise events
      - callend when someone tries to invoke a function that doesn't exists
      - called when the wrong parameters are called for a function
      - for error handling
      - to avoid errors from function we call bubble up to our callers
  - - - false instead of exception
      - takes only 2300 gas
        
        safe against reentry
      - triggers code execution (fallback?)
      - is low level function
    - - throws exception instead of returning false
        
        is equivalent to require(x.send(y))
      - takes only 2300 gas
        
        safe against reentry
      - triggers code execution (fallback()?)
      - is high level function
      - will automatically revert if the send fails
    - - consumes the gas specified or all gas if not specified
      - not safe against reentry
      - compatible to contracts with fallback() methods that require more gas
      - low level
      - returns boolean instead of throwing an exception
    - - let customers withdraw some value instead of sending money directly to the customer
      - The customer is responsible for selecting the gas amount
      - send() or transfer() for push as it wastes not more than 2300 gas
      - use call.value()() for pull as it's the gas of the customer which would be wasted
    - - First check the state, then set the state and lastly interact with other contracts
        
        assert should check internal state
        
        consumes all remaining gas when failed
        
        require should check inputs
        
        refunds the remaining gas when failed
      - The famous DAO hack was possible by utilizing a reentry with a fallback function.
  - - - If no such function exists, the contract cannot receive Ether through regular transactions and throws an exception.