如何使用 Merklized 抽象语法树压缩智能合约

contract TimedCommit {
  bytes aliceHash;
  PubKey alice;
  PubKey bob;
  public function open(bytes aliceNonce, Sig aliceSig) {
    require(sha256(aliceNonce) == this.aliceHash);
    require(checkSig(aliceSig, this.alice));
  }
  public function forfeit(Sig aliceSig, Sig bobSig) {
    require(checkSig(aliceSig, this.alice));
    require(checkSig(bobSig, this.bob));
  }
}

contract ContractOfManyBranches {
    public function branchA() { }
    public function branchB() { }
    public function branchC() { }
    public function branchC() { }
    // ... more branches
}

contract MAST {
    static const int DEPTH = 4;
    Sha256 merkleRoot;
    public function main(bytes branchScript, MerklePath merklePath, SigHashPreimage txPreimage) {
        require(Tx.checkPreimage(txPreimage));
        // validate branchScript is from the merkle tree
        require(calMerkleRoot(branchScript, merklePath) == this.merkleRoot);
        // "P2SH": use branch script as the new locking script, while maintaining value
        bytes output = Util.buildOutput(branchScript, Util.value(txPreimage));
        require(hash256(output) == Util.hashOutputs(txPreimage));
    }
    static function calMerkleRoot(bytes leaf, MerklePath merklePath) : Sha256 {
        Sha256 root = sha256(leaf);
        loop (DEPTH) : i {
            Sibling s = merklePath[i];
            root = s.left ? sha256(s.hash + root) : sha256(root + s.hash);
        }
        return root;
    }
}