Updated example contract.

index.html

@@ -61,61 +61,69 @@ Version: <span id="version">(loading)</span>
 <input id="optimize" type="checkbox"><label for="optimize">optimize</label>
 </div>
 <div id="input">contract Ballot {
+    struct Voter {
+        uint weight;
+        bool voted;
+        uint8 vote;
+        address delegate;
+    }
+    struct Proposal {
+        uint voteCount;
+    }
+
+    address chairperson;
+    mapping(address => Voter) voters;
+    Proposal[] proposals;
+
     // Create a new ballot with $(_numProposals) different proposals.
     function Ballot(uint8 _numProposals) {
-        address sender = msg.sender;
-        chairperson = sender;
-        numProposals = _numProposals;
+        chairperson = msg.sender;
+        voters[chairperson].weight = 1;
+        proposals.length = _numProposals;
     }
 
     // Give $(voter) the right to vote on this ballot.
     // May only be called by $(chairperson).
     function giveRightToVote(address voter) {
-        if (msg.sender != chairperson || voted[voter]) return;
-        voterWeight[voter] = 1;
+        if (msg.sender != chairperson || voters[voter].voted) return;
+        voters[voter].weight = 1;
     }
 
     // Delegate your vote to the voter $(to).
     function delegate(address to) {
-        address sender = msg.sender;
-        if (voted[sender]) return;
-        while (delegations[to] != address(0) && delegations[to] != sender)
-            to = delegations[to];
-        if (to == sender) return;
-        voted[sender] = true;
-        delegations[sender] = to;
-        if (voted[to]) voteCounts[votes[to]] += voterWeight[sender];
-        else voterWeight[to] += voterWeight[sender];
+        Voter sender = voters[msg.sender]; // assigns reference
+        if (sender.voted) return;
+        while (voters[to].delegate != address(0) && voters[to].delegate != msg.sender)
+            to = voters[to].delegate;
+        if (to == msg.sender) return;
+        sender.voted = true;
+        sender.delegate = to;
+        Voter delegate = voters[to];
+        if (delegate.voted)
+            proposals[delegate.vote].voteCount += sender.weight;
+        else
+            delegate.weight += sender.weight;
     }
 
     // Give a single vote to proposal $(proposal).
     function vote(uint8 proposal) {
-        address sender = msg.sender;
-        if (voted[sender] || proposal >= numProposals) return;
-        voted[sender] = true;
-        votes[sender] = proposal;
-        voteCounts[proposal] += voterWeight[sender];
+        Voter sender = voters[msg.sender];
+        if (sender.voted || proposal >= proposals.length) return;
+        sender.voted = true;
+        sender.vote = proposal;
+        proposals[proposal].voteCount += sender.weight;
     }
 
     function winningProposal() constant returns (uint8 winningProposal) {
         uint256 winningVoteCount = 0;
-        uint8 proposal = 0;
-        while (proposal < numProposals) {
-            if (voteCounts[proposal] > winningVoteCount) {
-                winningVoteCount = voteCounts[proposal];
+        for (uint8 proposal = 0; proposal < proposals.length; proposal++) {
+            if (proposals[proposal].voteCount > winningVoteCount) {
+                winningVoteCount = proposals[proposal].voteCount;
                 winningProposal = proposal;
             }
             ++proposal;
         }
     }
-
-    address chairperson;
-    uint8 numProposals;
-    mapping(address => uint256) voterWeight;
-    mapping(address => bool) voted;
-    mapping(address => uint8) votes;
-    mapping(address => address) delegations;
-    mapping(uint8 => uint256) voteCounts;
 }
 </div>
 <div id="output"></div>