axic

//
// In Solidity, a mapping is like a hashmap and works with `string` like this:
//   mapping (string => uint) a; 
//
// However it doesn't support accessors where string is a key:
//   mapping (string => uint) public a;
//
// "Internal compiler error: Accessors for mapping with dynamically-sized keys not yet implemented."
//
// An accessor returns uint when called as `a(string)`.

axic

//
// Big number library in Solidity for the purpose of implementing modexp.
//
// Should have a similar API to https://github.com/ethereum/EIPs/issues/101
//
// Internally bignumbers are represented as an uint array of 128 bit values.
//
// NOTE: it assumes usage with "small" (<256bit) exponents (such as in RSA)
//

konradkonrad

#!/usr/bin/env bash

# Usage:
# ./solc [options] inputfile > outfile

# Notes:
# - file i/o is limited to the current directory
# - this works with the pyethereum solc_wrapper

docker run -i --rm --user $(id -u):$(id -g) -v $(pwd):/tmp --workdir /tmp ethereum/solc:0.4.18 $@

Arachnid

/**
 * Base contract that all upgradeable contracts should use.
 * 
 * Contracts implementing this interface are all called using delegatecall from
 * a dispatcher. As a result, the _sizes and _dest variables are shared with the
 * dispatcher contract, which allows the called contract to update these at will.
 * 
 * _sizes is a map of function signatures to return value sizes. Due to EVM
 * limitations, these need to be populated by the target contract, so the
 * dispatcher knows how many bytes of data to return from called functions.

alexvandesande

/*

The contract is free software: you can redistribute it and/or modify
it under the terms of the GNU lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

The contract is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

Creator.sol

contract Creator {
    function newContract(bytes data) public returns (address) {
        address theNewContract;
        uint s = data.length;

        assembly {
            calldatacopy(mload(0x40), 68, s)
            theNewContract := create(callvalue, mload(0x40), s)
        }

chriseth

This gist shows how formal conditions of Solidity smart contracts can be automatically verified even in the presence of potential re-entrant calls from other contracts.

Solidity already supports formal verification of some contracts that do not make calls to other contracts. This of course excludes any contract that transfers Ether or tokens.

The Solidity contract below models a crude crowdfunding contract that can hold Ether and some person can withdraw Ether according to their shares. It is missing the actual access control, but the point that wants to be made

xavierlepretre

const Promise = require("bluebird");
const sequentialPromise = require("./sequentialPromise.js");

/**
 * @param {!string | !Array.<!string>} txHash, a transaction hash or an array of transaction hashes.
 * @param {Number} interval, in seconds.
 * @returns {!Promise.<!object> | !Promise.<!Array.<!object>>} the receipt or an array of receipts.
 */
module.exports = function getTransactionReceiptMined(txHash, interval) {
    const self = this;

chriseth

Having seen @pirapira's sketch of Bamboo ( https://github.com/pirapira/bamboo/ ), which proposed to add better control about the "smart contract program flow", even across calls, I thought that this should certainly be added to Solidity, and actually, it might even be possible now to a certain degree using inline assembly.

The problem is that with many functions in a contract, it is not always clear which can be called at which stage in the contract's lifetime. Certain smart contracts would be easier to understand if written as follows:

indiesquidge

/* 
 Let us re-create `Promise.all`

 `Promise.all` method returns a promise that resolves when all of the promises in the iterable argument have resolved, 
 or rejects with the reason of the first passed promise that rejects.
 
 Read more about `Promise.all` on MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all
 
 A basic example would be something like this: