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48 lines
2.2 KiB
48 lines
2.2 KiB
3 weeks ago
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= ERC-6909
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ERC-6909 is a draft EIP that draws on ERC-1155 learnings since it was published in 2018. The main goals of ERC-6909 is to decrease gas costs and complexity--this is mainly accomplished by removing batching and callbacks.
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TIP: To understand the inspiration for a multi token standard, see the xref:erc1155.adoc#multi-token-standard[multi token standard] section within the EIP-1155 docs.
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== Changes from ERC-1155
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There are three main changes from ERC-1155 which are as follows:
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. The removal of batch operations.
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. The removal of transfer callbacks.
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. Granularization in approvals--approvals can be set globally (as operators) or as amounts per token (inspired by ERC20).
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== Constructing an ERC-6909 Token Contract
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We'll use ERC-6909 to track multiple items in a game, each having their own unique attributes. All item types will by minted to the deployer of the contract, which we can later transfer to players. We'll also use the xref:api:token/ERC6909.adoc#ERC6909Metadata[`ERC6909Metadata`] extension to add decimals to our fungible items (the vanilla ERC-6909 implementation does not have decimals).
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For simplicity, we will mint all items in the constructor--however, minting functionality could be added to the contract to mint on demand to players.
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TIP: For an overview of minting mechanisms, check out xref:erc20-supply.adoc[Creating ERC-20 Supply].
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Here's what a contract for tokenized items might look like:
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[source,solidity]
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----
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include::api:example$token/ERC6909/ERC6909GameItems.sol[]
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----
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Note that there is no content URI functionality in the base implementation, but the xref:api:token/ERC6909.adoc#ERC6909ContentURI[`ERC6909ContentURI`] extension adds it. Additionally, the base implementation does not track total supplies, but the xref:api:token/ERC6909.adoc#ERC6909TokenSupply[`ERC6909TokenSupply`] extension tracks the total supply of each token id.
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Once the contract is deployed, we will be able to query the deployer’s balance:
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[source,javascript]
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----
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> gameItems.balanceOf(deployerAddress, 3)
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1000000000
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----
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We can transfer items to player accounts:
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[source,javascript]
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----
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> gameItems.transfer(playerAddress, 2, 1)
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> gameItems.balanceOf(playerAddress, 2)
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1
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> gameItems.balanceOf(deployerAddress, 2)
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0
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----
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