chriseth

To increase decentralization, it would be great to have a verified repository of smart contract source codes. Due to the metadata being part of the bytecode, we should have everything that is needed to actually perform the verification. This repository could be an actual repository on github, where people can create pull requests to have their smart contract code compiled and verified. There could be a CI job that does the verification as follows:

• fetch the bytecode from the chain via infura or another service
• install the correct compiler version using npm
• only flag the PR green, if the compilation output matches the bytecode

If the directory name is the address of the contract, the source code should be easy to find, even if multiple

chriseth

// Compile the following using ``solc --strict-assembly example.yul``
object "MyContract" {
  code {
    // this is the constructor.
    // store the creator in the first storage slot
    sstore(0, caller())
    // now return the runtime code using the special functions
    datacopy(0, dataoffset("Runtime"), datasize("Runtime"))
    return(0, datasize("Runtime"))
  }

chriseth

EasterHegg 18 Workshop: Smart Contracts on Ethereum

Requirements:

• Chrome/ium or Firefox
• Metamask

Coding your first smart contract!

a. Setting up Metamask

chriseth

diff --git a/docs/abi-spec.rst b/docs/abi-spec.rst
index e39c8861..8095a3b7 100644
--- a/docs/abi-spec.rst
+++ b/docs/abi-spec.rst
@@ -6,17 +6,19 @@
 Application Binary Interface Specification
 ******************************************
 
-Basic design
+Basic Design

chriseth

contract MyToken {
    function MyToken() {
        assembly {
            // Store the creator at storage slot zero
            sstore(0, caller())
        }
    }
    function () payable {
        assembly {
            // Protection against sending Ether

chriseth

Answers to Deep Questions about Solidity

The following list of questions was taken from https://www.reddit.com/r/ethereum/comments/72reba/do_you_have_deep_questions_about_solidity_or_the/

An updated summary on the different ways one could have two contracts interact (DELEGATECALL, STATICCALL, libraries, all that stuff) with clear pros/cons for each (gas cost, whether it requires EVM assembly directives, etc)

Question by /u/drcode

I won't talk about low-level opcodes here because of the brevity of the answer. In general, there are four ways functions can be called in Solidity:

chriseth

// This file is MIT Licensed.
//
// Copyright 2017 Christian Reitwiessner
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF O

chriseth

contract PatriciaTree {
    // List of all keys, not necessarily sorted.
    bytes[] keys;
    // Mapping of hash of key to value
    mapping (bytes32 => bytes) values;

    struct Label {
        bytes32 data;
        uint length;
    }

chriseth

bool ExpresionCompiler::visit(BinaryExpression const& _expr)
{
    // noteResult returns the julia-equivalent of the expression.
    // it also inserts a comment containing the source location of _expr
    // Anything inside angle brackets is looked up in the table passed
    // as third argument and a plain string replacement is performed.
    // The convert function calls visit recursively (or instanciates a
    // new AST walker) and returns what was supplied to "noteResult".

chriseth

{
// Some elementary helpers ---------------------------------------

function memptr() -> addr
{
    addr := 0x40
}
function allocate(size) -> addr
{
    addr := mload(memptr())