LLL Examples for PoC 5

Key-Value Publisher

{
  [[69]] (caller)
  (return 0 (lll
    (when (= (caller) @@69)
      (for {} (< @i (calldatasize)) [i](+ @i 64)
        [[ (calldataload @i) ]] (calldataload (+ @i 32))
      )
    )
  0))
}

Name Registrar

A simple name registeration service. Names (represented as 32-byte values whose left-most bytes store an ASCII string) are stored in the address space of the contract leading to the (160-bit ethereum) address of the name's owner. The owner addresses are similarly stored in the contract's address space with a value leading back to the name.

;; Initialiser...
{
  [[(address)]] "NameReg"
  [["NameReg"]] (address)
  [[69]] (caller)

  (return 0 (lll
    ;; If there's at least one argument
    (if (calldatasize)
      {
        ;; Stop if the first arg (name) has already been registered.
        (when @@(calldataload 0) (stop))

        ;; Store sender at name, and name at sender.
        (when @@(caller) [[@@(caller)]] 0)
        [[(calldataload 0)]] (caller)
        [[(caller)]] (calldataload 0)
        (stop)
      }

      ;; No arguments - either deregister or suicide (if it's from owner's address).
      {
        ;; Suicide if it's from owner's address.
        (when (= (caller) @@69) (suicide (caller)))

        ;; Otherwise, just deregister any name sender has, if they are registered.
        (when @@(caller) {
          [[@@(caller)]] 0
          [[(caller)]] 0
        })
        (stop)
      }
    )
  0))
}

Bank

A very simple bank. You can send ether in a transaction to load your account with funds. Withdraw your ether by specifying a 32-byte data argument of the amount to withdraw. Withdraw to a different account by specifying a second data argument with the account.

{
  [0] "Bank"
  (call (- (gas) 100) 0x2d0aceee7e5ab874e22ccf8d1a649f59106d74e8 0 0 4 0 0)

  (return 0 (lll {
    (if (>= @@(caller) (calldataload 0))
      ;; Withdrawal:
      {
        ;; Subtract the value from the balance of the account
        [[ (caller) ]] (- @@(caller) (calldataload 0))
        ;; Transfer the funds either to...
        (if (<= (calldatasize) 32)
          (call (- (gas) 100) (caller) (calldataload 0) 0 0 0 0)  ; ...the sender...
          (call (- (gas) 100) (calldataload 32) (calldataload 0) 0 0 0 0)  ; ...or the supplied account.
        )
      }
      ;; Deposit; just increase the account balance by that amount.
      [[(caller)]] (+ @@(caller) (callvalue))
    )
  } 0))
}

Splitter

Simple cash splitter; splits the value sent amongst each of the addresses given as data items.

{
  [0] "Splitter"
  (call (- (gas) 100) 0x2d0aceee7e5ab874e22ccf8d1a649f59106d74e8 0 0 8 0 0)

  (return 0 (lll {
    [count] (/ (calldatasize) 32)
    [pay] (/ (callvalue) @count)

    ;; Cycle through each address
    (for {} (< @i @count) [i](+ @i 1)
      ;; Send to 'i'th argument (assuming it's an address).
      (call (- (gas) 100) (calldataload (* @i 32)) @pay 0 0 0 0)
    )
  } 0))
}

Currency

{
  ;; Give caller a whole bunch of cash.
  [[ (caller) ]]: 0x1000000000000000000000000
  ;; Register with the NameReg contract.
  [0] "GavCoin"
  (call (- (gas) 100) 0x2d0aceee7e5ab874e22ccf8d1a649f59106d74e8 0 0 7 0 0)

  (return 0 (lll {
    (when (!= (calldatasize) 64) (stop))      ; stop if there's not enough data passed.
    [fromBal] @@(caller)
    [toBal]: @@(calldataload 0)
    [value]: (calldataload 32)
    (when (< @fromBal @value) (stop))         ; stop if there's not enough for the transfer.
    [[ (caller) ]]: (- @fromBal @value)       ; subtract amount from caller's account.
    [[ (calldataload 0) ]]: (+ @toBal @value) ; add amount on to recipient's account.
  } 0))
}

Timevault

{
  ;; Register with the NameReg contract.
  [0] "TimeVault"
  (call (- (gas) 100) 0x2d0aceee7e5ab874e22ccf8d1a649f59106d74e8 0 0 9 0 0)

  ;; Register the owner of the money in the contract
  [['owner]]:(caller)
  ;; Initialize the waiting period to 3600 seconds (60 minutes)
  [['waiting_period]]:3600

  (return 0 (lll
    ;; Owner starts a withdrawal authorisation
    (if (&& (= (caller) @@'owner) (= (calldataload 0) "withdrawal"))
      [['withdrawal_start]]:(timestamp)
      ;; Else, when owner finalises withdrawal after waiting period and time has elapsed
      (when (&& (= (caller) @@'owner) (= (calldataload 0) "finalize")
                 (< (+ @@'withdrawal_start @@'waiting_period) (timestamp)))
        ;; Send money to sender
        (suicide @@'owner)
      )
    )
  0))
}