vietlq

module MaybeMonad = struct
	type 'a t = None | Maybe of 'a

	let return (a: 'a) : 'a t = Maybe a

	let (>>=) (m: 'a t) (f: 'a -> 'b t) : 'b t = match m with
		| None -> None
		| Maybe a -> f a

	let get (m: 'a t) (a: 'a) = match m with

vietlq

type z
type 'a s

(* Sadly enough, without kind restrictions, this still allows nonsense types like *)
type nonsense = int s
(* GHC 7.6 supports this (lifting types to kinds & kind constraints) ;-) *)

type (_, _) llist =
  | Nil : (z, 'a) llist
  | Cons : ('a * ('l, 'a) llist) -> ('l s, 'a) llist

vietlq

/**
 * 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.

vietlq

/***
* Shoutouts:
* 
* Bytecode origin https://www.reddit.com/r/ethereum/comments/6ic49q/any_assembly_programmers_willing_to_write_a/dj5ceuw/
* Modified version of Vitalik's https://www.reddit.com/r/ethereum/comments/6c1jui/delegatecall_forwarders_how_to_save_5098_on/
* Credits to Jorge Izquierdo (@izqui) for coming up with this design here: https://gist.github.com/izqui/7f904443e6d19c1ab52ec7f5ad46b3a8
* Credits to Stefan George (@Georgi87) for inspiration for many of the improvements from Gnosis Safe: https://github.com/gnosis/gnosis-safe-contracts
* 
* This version has many improvements over the original @izqui's library like using REVERT instead of THROWing on failed calls.
* It also implements the awesome design pattern for initializing code as seen in Gnosis Safe Factory: https://github.com/gnosis/gnosis-safe-contracts/blob/master/contracts/ProxyFactory.sol

vietlq

// https://gcc.gnu.org/onlinedocs/gcc-4.7.2/gcc/Function-Attributes.html
// https://infektor.net/posts/2017-01-19-using-cpp17-attributes-today.html
// Compiler flags: -Wall -Werror -Wextra -pedantic -Wunused-result -std=c++11
// Suggested macro names: HANDLE_OUTPUT / NODISCARD / MUST_HANDLE

#define HANDLE_OUTPUT __attribute__((warn_unused_result))

HANDLE_OUTPUT int critical_func()
{
    return 1234;

vietlq

// Bytecode origin https://www.reddit.com/r/ethereum/comments/6ic49q/any_assembly_programmers_willing_to_write_a/dj5ceuw/
// Modified version of Vitalik's https://www.reddit.com/r/ethereum/comments/6c1jui/delegatecall_forwarders_how_to_save_5098_on/
// Credits to Jordi Baylina for this way of deploying contracts https://gist.github.com/jbaylina/e8ac19b8e7478fd10cf0363ad1a5a4b3

// Forwarder is slightly modified to only return 256 bytes (8 normal returns)

// Deployed Factory in Kovan: https://kovan.etherscan.io/address/0xaebc118657099e2110c90494f48b3d21329b23eb

// Example of a Forwarder deploy using the Factory: https://kovan.etherscan.io/tx/0xe995dd023c8336685cb819313d933ae8938009f9c8c0e1af6c57b8be06986957
// Just 66349 gas per contract

vietlq

# JavaScript: HTML5 File drop
# param1 (WebElement): Drop area element
# param2 (int): Optional - Drop offset x relative to the top/left corner of the drop area. Center if 0.
# param3 (int): Optional - Drop offset y relative to the top/left corner of the drop area. Center if 0.

# load minified script
JS_DROP_FILE = "for(var b=arguments[0],k=arguments[1],l=arguments[2],c=b.ownerDocument,m=0;;){var e=b.getBoundingClientRect(),g=e.left+(k||e.width/2),h=e.top+(l||e.height/2),f=c.elementFromPoint(g,h);if(f&&b.contains(f))break;if(1<++m)throw b=Error('Element not interractable'),b.code=15,b;b.scrollIntoView({behavior:'instant',block:'center',inline:'center'})}var a=c.createElement('INPUT');a.setAttribute('type','file');a.setAttribute('style','position:fixed;z-index:2147483647;left:0;top:0;');a.onchange=function(){var b={effectAllowed:'all',dropEffect:'none',types:['Files'],files:this.files,setData:function(){},getData:function(){},clearData:function(){},setDragImage:function(){}};window.DataTransferItemList&&(b.i

vietlq

function readFile(file) {
    var reader = new FileReader();
    var deferred = $.Deferred();

    reader.onload = function(event) {
        deferred.resolve(event.target.result);
    };

    reader.onerror = function() {
        deferred.reject(this);

vietlq

import React, {PropTypes} from 'react';
import classNames from 'classnames';

class BatchDropZone extends React.Component {

    static propTypes = {

        // function that recieves an array of files
        receiveFiles: PropTypes.func.isRequired,

vietlq

rundown of different scripts and what is what and what goes where.

• the prevoutScript is the script of the output being spend
• the redeemScript is the script that is used to solve the P2SH
• the signatureScript is the script that is taken into the signatureHash for signing
• the witnessRedeemScript is the script that is used to solve the P2WSH
• the scriptSig is what goes into the input.scriptSig when serializing the TX
• the witnessScript is what goes into the input.witness when serializing the TX

for a P2KH