Kai kaichen

Recently Executed Contracts with Issues in EIP 1884

Background

EIP 1884 is set to be implemented into the upcoming Ethereum 'Istanbul' hard fork. It

increases the cost of opcode SLOAD from 200 to 800 gas
increases the cost of BALANCE and EXTCODEHASH from 400 to 700 gas
adds a new opcode SELFBALANCE with cost 5.

OP_CHECKDATASIG

OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY check whether a signature is valid with respect to a message and and a public key. The message is restricted to exactly 256 bits, if longer messages are to be signed, it is recommended to sign the messages hash.

OP_CHECKDATASIG permits data to be imported into a script, and have its validity checked against some signing authority such as an "Oracle".

OP_CHECKDATASIG and OP_CHECKDATASIGVERIFY are designed to be implemented similarly to OP_CHECKSIG [1]. Conceptually, one could imagine OP_CHECKSIG functionality being replaced by OP_CHECKDATASIG, along with a separate Op Code to create a hash from the transaction based on the SigHash algorithm.

The Story of NPM and Yarn

In the beginning there was NPM, and for a time it was good. Packages went forth and multiplied. The New Gods proclaimed the great demon Dependency Management had been slain. But The Old Gods knew better, for they had seen much and knew that the demon can never be killed, only held at bay.

The Old Gods were ignored. In the folly of a young age grew an abundance of packages and with them grew the scourge of dependency. In the depths beneath the earth, in a place beyond memory, the great demon stirred.

The first sign something was wrong was non-deterministic package version mismatches. “This is fine!” The New Gods declared. “A temporary setback, nothing more! We can fix it.” And so they introduced shrinkwrap, a lamp to combat the growing darkness.

But it proved to be too little, too late, and dusk continued to fall. The New Gods suffered their first major defeat at the [Battle of Left-pad](https://www.theregister.co.uk/2016/03/23/npm_left_

A top-down look into Elixir (for Rubyists)

Phoenix (as "Rails for Elixir")
- Rails and Phoenix can get suspiciously similar
- A code sample:
controller.rb

Hello, visitors! If you want an updated version of this styleguide in repo form with tons of real-life examples… check out Trellisheets! https://github.com/trello/trellisheets

Trello CSS Guide

“I perfectly understand our CSS. I never have any issues with cascading rules. I never have to use !important or inline styles. Even though somebody else wrote this bit of CSS, I know exactly how it works and how to extend it. Fixes are easy! I have a hard time breaking our CSS. I know exactly where to put new CSS. We use all of our CSS and it’s pretty small overall. When I delete a template, I know the exact corresponding CSS file and I can delete it all at once. Nothing gets left behind.”

You often hear updog saying stuff like this. Who’s updog? Not much, who is up with you?

	class EOSKey {
	// Generate EOS owner pk and active pk from mnemonic
	private static List<byte[]> calcDefaultKeys(List<String> mnemonics, String path) {
	// Step 1. Get chaincode at m/44'/194'
	// EOS Coin type is defined at SLIP44 ref: https://github.com/satoshilabs/slips/blob/master/slip-0044.md
	// We believe that chaincode are more private
	MnemonicUtil.validateMnemonics(mnemonics);
	DeterministicSeed seed = new DeterministicSeed(mnemonics, null, "", 0L);
	DeterministicKeyChain keyChain = DeterministicKeyChain.builder().seed(seed).build();
	DeterministicKey parent = keyChain.getKeyByPath(BIP44Util.generatePath(path), true);

	# 你可以从该 URL 下载这个配置文件: http://surge.run/config-example/ios.conf
	# 用编辑器编辑后，再通过 iTunes, URL, AirDrop 或者 iCloud Drive 复制回 iOS 设备
	# Version 2.0

	[General]
	# 日志等级: warning, notify, info, verbose (默认值: notify)
	loglevel = notify
	# 跳过某个域名或者 IP 段，这些目标主机将不会由 Surge Proxy 处理。(在 macOS
	# 版本中，如果启用了 Set as System Proxy, 那么这些值会被写入到系统网络代理
	# 设置中.)

	tell application "Google Chrome"

	set tab_list to every tab in the front window

	repeat with the_tab in tab_list
	set the_url to the URL of the_tab
	tell application "Safari" to open location the_url
	end repeat

	end tell

	let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]

	extension Array {
	func splitBy(subSize: Int) -> [[Element]] {
	return 0.stride(to: self.count, by: subSize).map { startIndex in
	let endIndex = startIndex.advancedBy(subSize, limit: self.count)
	return Array(self[startIndex ..< endIndex])
	}
	}
	}

	#import <Foundation/Foundation.h>
	#import "RCTBridgeModule.h"

	#define RCT_EXTERN_MODULE(objc_name, objc_supername) \
	RCT_EXTERN_REMAP_MODULE(objc_name, objc_name, objc_supername)

	#define RCT_EXTERN_REMAP_MODULE(js_name, objc_name, objc_supername) \
	objc_name : objc_supername \
	@end \
	@interface objc_name (RCTExternModule) <RCTBridgeModule> \