A contract that illustrates LLL contract structure

structure.lll

;;;; --------------------------------------------------------------------------
;;;; @title A contract that illustrates LLL contract structure.
;;;; @author Daniel Ellison <[email protected]>

(seq

  ;; Define the macros for this contract.
  (include "macros.lll")

  ;;; -------------------------------------------------------------------------
  ;;; INIT

  ;; Our constructor is marked as 'payable: false' in its ABI specification,
  ;; so we abort if any ETH was passed in during the deployment process.
  (when (callvalue)
    (panic))

  ;; Store the single constructor argument.
  (codecopy *scratch* (bytecodesize) 32)
  (sstore *parameter* (mload *scratch*))

  ;;; -------------------------------------------------------------------------
  ;;; CODE

  (returnlll
    (seq

      ;; Since the requested function ID could be used many times in a more
      ;; complex contract, we retrieve and save it for future use. This
      ;; technique is courtesy of Ben Edgington. See macros.lll for its
      ;; definition.
      get-function-id

      ;; ----------------------------------------------------------------------
      ;; @notice Returns the value passed into the constructor.
      ;; @dev Signature: getConstructorParameter()
      ;; @return The value passed into the constructor.

      (function *get-constructor-parameter*
        (seq unpayable

          ;; This takes the constructor parameter and stores it in memory at
          ;; *scratch*, which resolves to 0x00.
          (mstore *scratch* (sload *parameter*))

          ;; The 'return' operator takes a memory location and a length and
          ;; returns the data at that memory location of the specified length.
          (return *scratch* 32)))

      ;; ----------------------------------------------------------------------
      ;; @notice Fallback: No functions matched the function ID provided.

      (panic))))