Feature: ERC721 NFT Contract #250
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@0xNeshi The repository has been upgraded to a new site generator and the Markdown format to include code listings is slightly different. The CONTRIBUTING guidelines has been updated to reflect these changes. |
| {{#include ../../listings/applications/721/src/erc721.cairo}} | ||
| ``` | ||
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| There are other implementations, such as the [Open Zeppelin](https://docs.openzeppelin.com/contracts-cairo/0.7.0/erc721) one. |
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| # ERC721 Token | |||
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| Contracts that follow the [ERC721 Standard](https://eips.ethereum.org/EIPS/eip-721) are called ERC721 tokens. They are used to represent non-fungible assets. | |||
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Add a small comment to recommend reader to actually click and read the EIP to learn about all the erc721 interface specifications
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Would be nice to also add the optional ERC721Metadata an ERC721Enumerable interfaces
| pub trait IERC721<TContractState> { | ||
| fn balance_of(self: @TContractState, owner: ContractAddress) -> u256; | ||
| fn owner_of(self: @TContractState, token_id: u256) -> ContractAddress; | ||
| fn safe_transfer_from( | ||
| ref self: TContractState, | ||
| from: ContractAddress, | ||
| to: ContractAddress, | ||
| token_id: u256, | ||
| data: Span<felt252> | ||
| ); | ||
| fn transfer_from( | ||
| ref self: TContractState, from: ContractAddress, to: ContractAddress, token_id: u256 | ||
| ); | ||
| fn approve(ref self: TContractState, approved: ContractAddress, token_id: u256); | ||
| fn set_approval_for_all(ref self: TContractState, operator: ContractAddress, approved: bool); | ||
| fn get_approved(self: @TContractState, token_id: u256) -> ContractAddress; | ||
| fn is_approved_for_all( | ||
| self: @TContractState, owner: ContractAddress, operator: ContractAddress | ||
| ) -> bool; | ||
| fn mint(ref self: TContractState, to: ContractAddress, token_id: u256); | ||
| fn burn(ref self: TContractState, token_id: u256); | ||
| } |
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mint and burn are not part of the official ERC interface, add them in a separate interface to separate the official interface and your implementation.
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Add a small comment to explain why we don't have safeTransferFrom(address _from, address _to, uint256 _tokenId) (and that the same behavior can be obtained by calling safe_transfer_from(_from, _to, _tokenId, _data) with empty _data)
| fn mint(ref self: ContractState, to: ContractAddress, token_id: u256) { | ||
| assert(!to.is_zero(), Errors::INVALID_RECEIVER); | ||
| assert(self.owners.read(token_id).is_zero(), Errors::ALREADY_MINTED); | ||
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| self.balances.write(to, self.balances.read(to) + 1); | ||
| self.owners.write(token_id, to); | ||
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| self.emit(Transfer { from: Zero::zero(), to, token_id }); | ||
| } | ||
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| fn burn(ref self: ContractState, token_id: u256) { | ||
| let owner = self._require_owned(token_id); | ||
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| self.balances.write(owner, self.balances.read(owner) - 1); | ||
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| self.owners.write(token_id, Zero::zero()); | ||
| self.approvals.write(token_id, Zero::zero()); | ||
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| self.emit(Transfer { from: owner, to: Zero::zero(), token_id }); | ||
| } |
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Move these in the internal impl as _mint and _burn, and implement mint and burn in a separate interface impl block that call the internal functions
Issue(s): Close #197
Description
Implement a simple ERC721 contract inspired by OZ's implementation.
Note: should replace non-maintained PR #214
Checklist
./scripts/cairo_programs_verifier.shsuccessfully