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Arguments · 9

1. #1erc721
2. #2README.md
3. #3# erc721 — NFT (ERC-721 port) > ⚠️ **Experimental — generated with no human supervision** by the daily MCP pipeline (Solidity→Gno port). Not audited. See [r/moul/x/daily](https://github.com/moul/gno-contracts/blob/main/r/moul/x/daily/README.md). --- An idiomatic gno.land port of the Solidity **ERC-721** non-fungible token standard. Each token is a unique, sequentially-minted integer id owned by exactly one address. Ownership, per-owner balances and single-token approvals live in ordered `avl.Tree`s, so `Render` can list every token deterministically. `msg.sender` maps to `unsafe.PreviousRealm().Address()`, `require` to `panic`, and Solidity events to `chain.Emit` (`Mint`, `Transfer`, `Approval`). ## Transactions - `Mint(cur realm, to address) int64` — mint the next token id to `to`; returns the id. - `Transfer(cur realm, to address, id int64)` — move a token you own (or are approved for) to `to`; clears the approval. - `Approve(cur realm, spender address, id int64)` — owner grants `spender` the right to transfer token `id`. ## Read-only - `OwnerOf(id int64) address` — owner of a token (panics if it does not exist). - `BalanceOf(owner address) uint64` — number of tokens held by `owner`. - `TotalSupply() int64` — total tokens in circulation. - `Render(path string)` — Markdown: total supply + a token → owner → approved table. ## Example ``` Mint(cur, g1alice...) // -> tokenID 1 Mint(cur, g1alice...) // -> tokenID 2 Approve(cur, g1bob..., 1) // alice approves bob for token 1 Transfer(cur, g1carol..., 1) // owner alice sends token 1 to carol OwnerOf(1) // -> g1carol... BalanceOf(g1alice...) // -> 1 TotalSupply() // -> 2 ``` <!-- BEGIN GNOCONTRACTS FOOTER (generated by `make readmes`; do not edit below) --> --- Part of **[moul/gno-contracts](https://github.com/moul/gno-contracts)** — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage. **Dependency graph:**  > 🧪 **Highly experimental — potentially vibe-coded.** Not audited; may break, change, or be removed at any time. Do not use with anything of value. Full disclaimer: [DISCLAIMER](https://github.com/moul/gno-contracts/blob/main/DISCLAIMER.md). <!-- END GNOCONTRACTS FOOTER -->
4. #4erc721.gno
5. #5// Package erc721 is an idiomatic gno.land port of the Solidity ERC-721 // non-fungible token standard. Each token has a unique integer id owned by // exactly one address; ids are minted sequentially. Ownership, per-owner // balances and single-token approvals are kept in ordered avl trees so that // Render can iterate deterministically. package erc721 import ( "strconv" "chain" "chain/runtime/unsafe" "gno.land/p/nt/avl/v0" ) const ( name = "Gno NFT" symbol = "GNFT" ) var ( owners avl.Tree // tokenID (zero-padded string) -> address balances avl.Tree // owner address (string) -> uint64 approvals avl.Tree // tokenID (zero-padded string) -> approved address nextID int64 = 1 minted int64 // total tokens ever minted (== live supply, no burn) ) // key formats a token id into a zero-padded, lexicographically-sortable key. func key(id int64) string { s := strconv.FormatInt(id, 10) for len(s) < 12 { s = "0" + s } return s } // Mint creates the next token id and assigns it to `to`. Only sequential // minting is supported (id is returned via the Mint event). func Mint(cur realm, to address) int64 { if !to.IsValid() { panic("erc721: mint to invalid address") } id := nextID nextID++ minted++ owners.Set(key(id), to) balances.Set(to.String(), balanceOf(to)+1) chain.Emit("Mint", "to", to.String(), "tokenID", strconv.FormatInt(id, 10)) return id } // Transfer moves token `id` from the caller to `to`. The caller must own the // token (approvals are cleared on transfer). func Transfer(cur realm, to address, id int64) { if !to.IsValid() { panic("erc721: transfer to invalid address") } caller := unsafe.PreviousRealm().Address() from := ownerOf(id) // panics if the token does not exist if caller != from { // allow the single-token approved operator too if approvedOf(id) != caller { panic("erc721: caller is neither owner nor approved") } } if from == to { panic("erc721: transfer to current owner") } owners.Set(key(id), to) balances.Set(from.String(), balanceOf(from)-1) balances.Set(to.String(), balanceOf(to)+1) approvals.Remove(key(id)) // clear approval on transfer chain.Emit("Transfer", "from", from.String(), "to", to.String(), "tokenID", strconv.FormatInt(id, 10)) } // Approve grants `spender` the right to transfer token `id`. Only the current // owner may approve. func Approve(cur realm, spender address, id int64) { caller := unsafe.PreviousRealm().Address() owner := ownerOf(id) if caller != owner { panic("erc721: approve caller is not owner") } approvals.Set(key(id), spender) chain.Emit("Approval", "owner", owner.String(), "spender", spender.String(), "tokenID", strconv.FormatInt(id, 10)) } // --- read-only helpers (safe to call from tests and Render) --- // ownerOf returns the owner of token `id`, panicking if it does not exist. func ownerOf(id int64) address { v := owners.Get(key(id)) if v == nil { panic("erc721: query for nonexistent token") } return v.(address) } // approvedOf returns the approved address for token `id`, or the zero address. func approvedOf(id int64) address { v := approvals.Get(key(id)) if v == nil { return address("") } return v.(address) } // balanceOf returns how many tokens `owner` holds. func balanceOf(owner address) uint64 { v := balances.Get(owner.String()) if v == nil { return 0 } return v.(uint64) } // exists reports whether token `id` has been minted (and not since moved away). func exists(id int64) bool { return owners.Has(key(id)) } // totalSupply returns the number of tokens in circulation. func totalSupply() int64 { return minted } // OwnerOf is the exported read-only accessor for ownerOf. func OwnerOf(id int64) address { return ownerOf(id) } // BalanceOf is the exported read-only accessor for balanceOf. func BalanceOf(owner address) uint64 { return balanceOf(owner) } // TotalSupply is the exported read-only accessor for totalSupply. func TotalSupply() int64 { return totalSupply() } // Render displays collection metadata and a token -> owner table. func Render(path string) string { out := "# " + name + " (" + symbol + ")\n\n" out += "**Total supply:** " + strconv.FormatInt(totalSupply(), 10) + "\n\n" if owners.Size() == 0 { out += "_No tokens minted yet._\n" return out } out += "| Token ID | Owner | Approved |\n" out += "|---------:|-------|----------|\n" owners.Iterate("", "", func(k string, v interface{}) bool { owner := v.(address) id, _ := strconv.ParseInt(k, 10, 64) appr := approvedOf(id) apprStr := "—" if appr != address("") { apprStr = appr.String() } out += "| " + strconv.FormatInt(id, 10) + " | " + owner.String() + " | " + apprStr + " |\n" return false }) return out }
6. #6gnomod.toml
7. #7module = "gno.land/r/moul/x/daily/erc721/v0" gno = "0.9"
8. #8/gno.MemPackageType
9. #9 MPUserProd