mirror of
https://github.com/SpaceVim/SpaceVim.git
synced 2025-01-25 02:30:04 +08:00
187 lines
6.2 KiB
Solidity
187 lines
6.2 KiB
Solidity
// Example contract from official documentation at https://github.com/ethereum/solidity/blob/v0.8.12/docs/examples/voting.rst
|
|
|
|
// SPDX-License-Identifier: GPL-3.0
|
|
// ^ comment
|
|
pragma solidity >=0.7.0 <0.9.0;
|
|
// ^ keyword
|
|
// ^ tag
|
|
|
|
import * as something from "anotherFile";
|
|
// ^ ^ ^ include
|
|
|
|
/// @title Voting with delegation.
|
|
// ^ attribute
|
|
contract Ballot {
|
|
// ^keyword
|
|
// ^ type
|
|
// This declares a new complex type which will
|
|
// be used for variables later.
|
|
// It will represent a single voter.
|
|
struct Voter {
|
|
// ^ type
|
|
uint weight; // weight is accumulated by delegation
|
|
// ^ type
|
|
// ^ field
|
|
bool voted; // if true, that person already voted
|
|
address delegate; // person delegated to
|
|
uint vote; // index of the voted proposal
|
|
}
|
|
|
|
// This is a type for a single proposal.
|
|
struct Proposal {
|
|
bytes32 name; // short name (up to 32 bytes)
|
|
uint voteCount; // number of accumulated votes
|
|
}
|
|
|
|
address public chairperson;
|
|
// ^ type
|
|
|
|
// This declares a state variable that
|
|
// stores a `Voter` struct for each possible address.
|
|
mapping(address => Voter) public voters;
|
|
// ^ ^ punctuation.bracket
|
|
// ^ punctuation.delimiter
|
|
|
|
// A dynamically-sized array of `Proposal` structs.
|
|
Proposal[] public proposals;
|
|
|
|
enum ActionChoices { GoLeft, GoRight, GoStraight, SitStill }
|
|
// ^ constant
|
|
|
|
/// Create a new ballot to choose one of `proposalNames`.
|
|
constructor(bytes32[] memory proposalNames) {
|
|
// ^ constructor
|
|
chairperson = msg.sender;
|
|
voters[chairperson].weight = 1;
|
|
|
|
// For each of the provided proposal names,
|
|
// create a new proposal object and add it
|
|
// to the end of the array.
|
|
for (uint i = 0; i < proposalNames.length; i++) {
|
|
// `Proposal({...})` creates a temporary
|
|
// Proposal object and `proposals.push(...)`
|
|
// appends it to the end of `proposals`.
|
|
proposals.push(Proposal({
|
|
name: proposalNames[i],
|
|
// ^ field
|
|
voteCount: 0
|
|
}));
|
|
}
|
|
}
|
|
|
|
// Give `voter` the right to vote on this ballot.
|
|
// May only be called by `chairperson`.
|
|
function giveRightToVote(address voter) external {
|
|
// ^ keyword.function
|
|
// ^ function
|
|
// ^ parameter
|
|
// If the first argument of `require` evaluates
|
|
// to `false`, execution terminates and all
|
|
// changes to the state and to Ether balances
|
|
// are reverted.
|
|
// This used to consume all gas in old EVM versions, but
|
|
// not anymore.
|
|
// It is often a good idea to use `require` to check if
|
|
// functions are called correctly.
|
|
// As a second argument, you can also provide an
|
|
// explanation about what went wrong.
|
|
require(
|
|
msg.sender == chairperson,
|
|
"Only chairperson can give right to vote."
|
|
);
|
|
require(
|
|
!voters[voter].voted,
|
|
"The voter already voted."
|
|
);
|
|
require(voters[voter].weight == 0);
|
|
voters[voter].weight = 1;
|
|
}
|
|
|
|
/// Delegate your vote to the voter `to`.
|
|
function delegate(address to) external {
|
|
// assigns reference
|
|
Voter storage sender = voters[msg.sender];
|
|
require(!sender.voted, "You already voted.");
|
|
|
|
require(to != msg.sender, "Self-delegation is disallowed.");
|
|
|
|
// Forward the delegation as long as
|
|
// `to` also delegated.
|
|
// In general, such loops are very dangerous,
|
|
// because if they run too long, they might
|
|
// need more gas than is available in a block.
|
|
// In this case, the delegation will not be executed,
|
|
// but in other situations, such loops might
|
|
// cause a contract to get "stuck" completely.
|
|
while (voters[to].delegate != address(0)) {
|
|
to = voters[to].delegate;
|
|
|
|
// We found a loop in the delegation, not allowed.
|
|
require(to != msg.sender, "Found loop in delegation.");
|
|
}
|
|
|
|
// Since `sender` is a reference, this
|
|
// modifies `voters[msg.sender].voted`
|
|
Voter storage delegate_ = voters[to];
|
|
|
|
// Voters cannot delegate to wallets that cannot vote.
|
|
require(delegate_.weight >= 1);
|
|
sender.voted = true;
|
|
sender.delegate = to;
|
|
if (delegate_.voted) {
|
|
// If the delegate already voted,
|
|
// directly add to the number of votes
|
|
proposals[delegate_.vote].voteCount += sender.weight;
|
|
} else {
|
|
// If the delegate did not vote yet,
|
|
// add to her weight.
|
|
delegate_.weight += sender.weight;
|
|
}
|
|
}
|
|
|
|
/// Give your vote (including votes delegated to you)
|
|
/// to proposal `proposals[proposal].name`.
|
|
function vote(uint proposal) external {
|
|
Voter storage sender = voters[msg.sender];
|
|
require(sender.weight != 0, "Has no right to vote");
|
|
require(!sender.voted, "Already voted.");
|
|
sender.voted = true;
|
|
sender.vote = proposal;
|
|
|
|
// If `proposal` is out of the range of the array,
|
|
// this will throw automatically and revert all
|
|
// changes.
|
|
proposals[proposal].voteCount += sender.weight;
|
|
}
|
|
|
|
/// @dev Computes the winning proposal taking all
|
|
/// previous votes into account.
|
|
function winningProposal() public view
|
|
returns (uint winningProposal_)
|
|
{
|
|
uint winningVoteCount = 0;
|
|
for (uint p = 0; p < proposals.length; p++) {
|
|
if (proposals[p].voteCount > winningVoteCount) {
|
|
winningVoteCount = proposals[p].voteCount;
|
|
winningProposal_ = p;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Calls winningProposal() function to get the index
|
|
// of the winner contained in the proposals array and then
|
|
// returns the name of the winner
|
|
function winnerName() external view
|
|
returns (bytes32 winnerName_)
|
|
{
|
|
winnerName_ = proposals[winningProposal()].name;
|
|
}
|
|
}
|
|
|
|
contract Another {
|
|
Ballot b = new Ballot(new bytes32[](1));
|
|
// ^ keyword.operator
|
|
}
|
|
|
|
// vim:ft=solidity
|