More on Web3 & Crypto
mbvissers.eth
3 years ago
Why does every smart contract seem to implement ERC165?
ERC165 (or EIP-165) is a standard utilized by various open-source smart contracts like Open Zeppelin or Aavegotchi.
What's it? You must implement? Why do we need it? I'll describe the standard and answer any queries.
What is ERC165
ERC165 detects and publishes smart contract interfaces. Meaning? It standardizes how interfaces are recognized, how to detect if they implement ERC165, and how a contract publishes the interfaces it implements. How does it work?
Why use ERC165? Sometimes it's useful to know which interfaces a contract implements, and which version.
Identifying interfaces
An interface function's selector. This verifies an ABI function. XORing all function selectors defines an interface in this standard. The following code demonstrates.
// SPDX-License-Identifier: UNLICENCED
pragma solidity >=0.8.0 <0.9.0;
interface Solidity101 {
function hello() external pure;
function world(int) external pure;
}
contract Selector {
function calculateSelector() public pure returns (bytes4) {
Solidity101 i;
return i.hello.selector ^ i.world.selector;
// Returns 0xc6be8b58
}
function getHelloSelector() public pure returns (bytes4) {
Solidity101 i;
return i.hello.selector;
// Returns 0x19ff1d21
}
function getWorldSelector() public pure returns (bytes4) {
Solidity101 i;
return i.world.selector;
// Returns 0xdf419679
}
}This code isn't necessary to understand function selectors and how an interface's selector can be determined from the functions it implements.
Run that sample in Remix to see how interface function modifications affect contract function output.
Contracts publish their implemented interfaces.
We can identify interfaces. Now we must disclose the interfaces we're implementing. First, import IERC165 like so.
pragma solidity ^0.4.20;
interface ERC165 {
/// @notice Query if a contract implements an interface
/// @param interfaceID The interface identifier, as specified in ERC-165
/// @dev Interface identification is specified in ERC-165.
/// @return `true` if the contract implements `interfaceID` and
/// `interfaceID` is not 0xffffffff, `false` otherwise
function supportsInterface(bytes4 interfaceID) external view returns (bool);
}We still need to build this interface in our smart contract. ERC721 from OpenZeppelin is a good example.
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/ERC721.sol)
pragma solidity ^0.8.0;
import "./IERC721.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/introspection/ERC165.sol";
// ...
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
// ...
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
return
interfaceId == type(IERC721).interfaceId ||
interfaceId == type(IERC721Metadata).interfaceId ||
super.supportsInterface(interfaceId);
}
// ...
}I deleted unnecessary code. The smart contract imports ERC165, IERC721 and IERC721Metadata. The is keyword at smart contract declaration implements all three.
Kind (interface).
Note that type(interface).interfaceId returns the same as the interface selector.
We override supportsInterface in the smart contract to return a boolean that checks if interfaceId is the same as one of the implemented contracts.
Super.supportsInterface() calls ERC165 code. Checks if interfaceId is IERC165.
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
return interfaceId == type(IERC165).interfaceId;
}So, if we run supportsInterface with an interfaceId, our contract function returns true if it's implemented and false otherwise. True for IERC721, IERC721Metadata, andIERC165.
Conclusion
I hope this post has helped you understand and use ERC165 and why it's employed.
Have a great day, thanks for reading!
The Verge
3 years ago
Bored Ape Yacht Club creator raises $450 million at a $4 billion valuation.
Yuga Labs, owner of three of the biggest NFT brands on the market, announced today a $450 million funding round. The money will be used to create a media empire based on NFTs, starting with games and a metaverse project.
The team's Otherside metaverse project is an MMORPG meant to connect the larger NFT universe. They want to create “an interoperable world” that is “gamified” and “completely decentralized,” says Wylie Aronow, aka Gordon Goner, co-founder of Bored Ape Yacht Club. “We think the real Ready Player One experience will be player run.”
Just a few weeks ago, Yuga Labs announced the acquisition of CryptoPunks and Meebits from Larva Labs. The deal brought together three of the most valuable NFT collections, giving Yuga Labs more IP to work with when developing games and metaverses. Last week, ApeCoin was launched as a cryptocurrency that will be governed independently and used in Yuga Labs properties.
Otherside will be developed by “a few different game studios,” says Yuga Labs CEO Nicole Muniz. The company plans to create development tools that allow NFTs from other projects to work inside their world. “We're welcoming everyone into a walled garden.”
However, Yuga Labs believes that other companies are approaching metaverse projects incorrectly, allowing the startup to stand out. People won't bond spending time in a virtual space with nothing going on, says Yuga Labs co-founder Greg Solano, aka Gargamel. Instead, he says, people bond when forced to work together.
In order to avoid getting smacked, Solano advises making friends. “We don't think a Zoom chat and walking around saying ‘hi' creates a deep social experience.” Yuga Labs refused to provide a release date for Otherside. Later this year, a play-to-win game is planned.
The funding round was led by Andreessen Horowitz, a major investor in the Web3 space. It previously backed OpenSea and Coinbase. Animoca Brands, Coinbase, and MoonPay are among those who have invested. Andreessen Horowitz general partner Chris Lyons will join Yuga Labs' board. The Financial Times broke the story last month.
"META IS A DOMINANT DIGITAL EXPERIENCE PROVIDER IN A DYSTOPIAN FUTURE."
This emerging [Web3] ecosystem is important to me, as it is to companies like Meta,” Chris Dixon, head of Andreessen Horowitz's crypto arm, tells The Verge. “In a dystopian future, Meta is the dominant digital experience provider, and it controls all the money and power.” (Andreessen Horowitz co-founder Marc Andreessen sits on Meta's board and invested early in Facebook.)
Yuga Labs has been profitable so far. According to a leaked pitch deck, the company made $137 million last year, primarily from its NFT brands, with a 95% profit margin. (Yuga Labs declined to comment on deck figures.)
But the company has built little so far. According to OpenSea data, it has only released one game for a limited time. That means Yuga Labs gets hundreds of millions of dollars to build a gaming company from scratch, based on a hugely lucrative art project.
Investors fund Yuga Labs based on its success. That's what they did, says Dixon, “they created a culture phenomenon”. But ultimately, the company is betting on the same thing that so many others are: that a metaverse project will be the next big thing. Now they must construct it.
Jeff John Roberts
3 years ago
Jack Dorsey and Jay-Z Launch 'Bitcoin Academy' in Brooklyn rapper's home
The new Bitcoin Academy will teach Jay-Marcy Z's Houses neighbors "What is Cryptocurrency."
Jay-Z grew up in Brooklyn's Marcy Houses. The rapper and Block CEO Jack Dorsey are giving back to his hometown by creating the Bitcoin Academy.
The Bitcoin Academy will offer online and in-person classes, including "What is Money?" and "What is Blockchain?"
The program will provide participants with a mobile hotspot and a small amount of Bitcoin for hands-on learning.
Students will receive dinner and two evenings of instruction until early September. The Shawn Carter Foundation will help with on-the-ground instruction.
Jay-Z and Dorsey announced the program Thursday morning. It will begin at Marcy Houses but may be expanded.
Crypto Blockchain Plug and Black Bitcoin Billionaire, which has received a grant from Block, will teach the classes.
Jay-Z, Dorsey reunite
Jay-Z and Dorsey have previously worked together to promote a Bitcoin and crypto-based future.
In 2021, Dorsey's Block (then Square) acquired the rapper's streaming music service Tidal, which they propose using for NFT distribution.
Dorsey and Jay-Z launched an endowment in 2021 to fund Bitcoin development in Africa and India.
Dorsey is funding the new Bitcoin Academy out of his own pocket (as is Jay-Z), but he's also pushed crypto-related charitable endeavors at Block, including a $5 million fund backed by corporate Bitcoin interest.
This post is a summary. Read full article here
You might also like
Jess Rifkin
3 years ago
As the world watches the Russia-Ukraine border situation, This bill would bar aid to Ukraine until the Mexican border is secured.
Although Mexico and Ukraine are thousands of miles apart, this legislation would link their responses.
Context
Ukraine was a Soviet republic until 1991. A significant proportion of the population, particularly in the east, is ethnically Russian. In February, the Russian military invaded Ukraine, intent on overthrowing its democratically elected government.
This could be the biggest European land invasion since WWII. In response, President Joe Biden sent 3,000 troops to NATO countries bordering Ukraine to help with Ukrainian refugees, with more troops possible if the situation worsened.
In July 2021, the US Border Patrol reported its highest monthly encounter total since March 2000. Some Republicans compare Biden's response to the Mexican border situation to his response to the Ukrainian border situation, though the correlation is unclear.
What the bills do
Two new Republican bills seek to link the US response to Ukraine to the situation in Mexico.
The Secure America's Borders First Act would prohibit federal funding for Ukraine until the US-Mexico border is “operationally controlled,” including a wall as promised by former President Donald Trump. (The bill even mandates a 30-foot-high wall.)
The USB (Ukraine and Southern Border) Act, introduced on February 8 by Rep. Matt Rosendale (R-MT0), would allow the US to support Ukraine, but only if the number of Armed Forces deployed there is less than the number deployed to the Mexican border. Madison Cawthorne introduced H.R. 6665 on February 9th (R-NC11).
What backers say
Supporters argue that even if the US should militarily assist Ukraine, our own domestic border situation should take precedence.
After failing to secure our own border and protect our own territorial integrity, ‘America Last' politicians on both sides of the aisle now tell us that we must do so for Ukraine. “Before rushing America into another foreign conflict over an Eastern European nation's border thousands of miles from our shores, they should first secure our southern border.”
“If Joe Biden truly cared about Americans, he would prioritize national security over international affairs,” Rep. Cawthorn said in a separate press release. The least we can do to secure our own country is send the same number of troops to the US-Mexico border to assist our border patrol agents working diligently to secure America.
What opponents say
The president has defended his Ukraine and Mexico policies, stating that both seek peace and diplomacy.
Our nations [the US and Mexico] have a long and complicated history, and we haven't always been perfect neighbors, but we have seen the power and purpose of cooperation,” Biden said in 2021. “We're safer when we work together, whether it's to manage our shared border or stop the pandemic. [In both the Obama and Biden administration], we made a commitment that we look at Mexico as an equal, not as somebody who is south of our border.”
No mistake: If Russia goes ahead with its plans, it will be responsible for a catastrophic and unnecessary war of choice. To protect our collective security, the United States and our allies are ready to defend every inch of NATO territory. We won't send troops into Ukraine, but we will continue to support the Ukrainian people... But, I repeat, Russia can choose diplomacy. It is not too late to de-escalate and return to the negotiating table.”
Odds of passage
The Secure America's Borders First Act has nine Republican sponsors. Either the House Armed Services or Foreign Affairs Committees may vote on it.
Rep. Paul Gosar, a Republican, co-sponsored the USB Act (R-AZ4). The House Armed Services Committee may vote on it.
With Republicans in control, passage is unlikely.
Sad NoCoiner
3 years ago
Two Key Money Principles You Should Understand But Were Never Taught
Prudence is advised. Be debt-free. Be frugal. Spend less.
This advice sounds nice, but it rarely works.
Most people never learn these two money rules. Both approaches will impact how you see personal finance.
It may safeguard you from inflation or the inability to preserve money.
Let’s dive in.
#1: Making long-term debt your ally
High-interest debt hurts consumers. Many credit cards carry 25% yearly interest (or more), so always pay on time. Otherwise, you’re losing money.
Some low-interest debt is good. Especially when buying an appreciating asset with borrowed money.
Inflation helps you.
If you borrow $800,000 at 3% interest and invest it at 7%, you'll make $32,000 (4%).
As money loses value, fixed payments get cheaper. Your assets' value and cash flow rise.
The never-in-debt crowd doesn't know this. They lose money paying off mortgages and low-interest loans early when they could have bought assets instead.
#2: How To Buy Or Build Assets To Make Inflation Irrelevant
Dozens of studies demonstrate actual wage growth is static; $2.50 in 1964 was equivalent to $22.65 now.
These reports never give solutions unless they're selling gold.
But there is one.
Assets beat inflation.
$100 invested into the S&P 500 would have an inflation-adjusted return of 17,739.30%.
Likewise, you can build assets from nothing. Doing is easy and quick. The returns can boost your income by 10% or more.
The people who obsess over inflation inadvertently make the problem worse for themselves. They wait for The Big Crash to buy assets. Or they moan about debt clocks and spending bills instead of seeking a solution.
Conclusion
Being ultra-prudent is like playing golf with a putter to avoid hitting the ball into the water. Sure, you might not slice a drive into the pond. But, you aren’t going to play well either. Or have very much fun.
Money has rules.
Avoiding debt or investment risks will limit your rewards. Long-term, being too cautious hurts your finances.
Disclaimer: This article is for entertainment purposes only. It is not financial advice, always do your own research.
Alex Mathers
3 years ago
12 habits of the zenith individuals I know
Calmness is a vital life skill.
It aids communication. It boosts creativity and performance.
I've studied calm people's habits for years. Commonalities:
Have mastered the art of self-humor.
Protectors take their job seriously, draining the room's energy.
They are fixated on positive pursuits like making cool things, building a strong physique, and having fun with others rather than on depressing influences like the news and gossip.
Every day, spend at least 20 minutes moving, whether it's walking, yoga, or lifting weights.
Discover ways to take pleasure in life's challenges.
Since perspective is malleable, they change their view.
Set your own needs first.
Stressed people neglect themselves and wonder why they struggle.
Prioritize self-care.
Don't ruin your life to please others.
Make something.
Calm people create more than react.
They love creating beautiful things—paintings, children, relationships, and projects.
Don’t hold their breath.
If you're stressed or angry, you may be surprised how much time you spend holding your breath and tightening your belly.
Release, breathe, and relax to find calm.
Stopped rushing.
Rushing is disadvantageous.
Calm people handle life better.
Are aware of their own dietary requirements.
They avoid junk food and eat foods that keep them healthy, happy, and calm.
Don’t take anything personally.
Stressed people control everything.
Self-conscious.
Calm people put others and their work first.
Keep their surroundings neat.
Maintaining an uplifting and clutter-free environment daily calms the mind.
Minimise negative people.
Calm people are ruthless with their boundaries and avoid negative and drama-prone people.