# Connect Four

> ⚠️ **Experimental — generated with no human supervision.** This realm was
> produced automatically by an MCP-driven agent to exercise the gno MCP server
> and tooling, and to generate test content for gno compilers, linters and
> formatters. **Not audited. Not for production.** Full context & folder README:
> [r/moul/x/daily](https://github.com/moul/gno-contracts/blob/main/r/moul/x/daily/README.md)

---


A two-player Connect Four realm on a 7-wide × 6-tall board. The game creator plays 🔴 and moves first; the named opponent plays 🟡. `Drop` enforces turn order by caller, rejects full and out-of-range columns, and detects a horizontal, vertical, or diagonal 4-in-a-row (or a draw). `Render` draws the board with 🔴🟡· and shows whose turn it is or who won.

Realm path: `gno.land/r/REPLACE_ADDR/connect4`

## Example calls

```
# create a game against another address (you are 🔴, returns the game id)
NewGame(g1zabc...opponent)   # -> 1

# drop discs into columns 0-6 (turns alternate, enforced by caller)
Drop(1, 3)   # 🔴 drops in column 3
Drop(1, 3)   # 🟡 drops in column 3 (called from opponent's key)

# view state
render:            # lists all games
render:1           # shows board for game 1
```

## What changed in v1

Two ports against [`v0`](https://github.com/moul/gno-contracts/tree/4f2df83869b80470eb81c48a82fdbe82256b8113/r/moul/x/daily/connect4), which stays live and untouched.

### Rendering

Identical behaviour to [`v0`](https://github.com/moul/gno-contracts/tree/4f2df83869b80470eb81c48a82fdbe82256b8113/r/moul/x/daily/connect4) apart from rendering, which now goes
through [`p/moul/kit/ui`](/p/moul/kit/ui/v0) instead of the local `short` helper.

**One address format.** Eleven realms carried their own `shortAddr` with four different truncation rules, so the same account rendered differently depending on which realm you opened. `ui.Addr` is that decision made once: 8 leading characters, an ellipsis, 4 trailing, in backticks.

### Storage

State moved from a hand-rolled `avl.Tree` + `nextID` + zero-padding helper to
[`p/moul/kit/store`](/p/moul/kit/store/v0), which keys entries by
[`seqid`](/p/nt/seqid/v0) instead of a fixed-width decimal string.

`v0` padded ids to width 12. Past that width the padding stops and the tree
orders `"1000000000000"` before `"999999999999"`, so every list this realm
renders would be wrong from that entry on. `store` keys are 8 big-endian bytes
whose order is numeric for every `uint64`, so there is no width left to outgrow.

`Game` loses its `ID` field, which the store now owns, so `Drop` emits with the
`gameID` it was already given and `renderGame` takes the id alongside the game.
`Drop`'s trailing `games.Set(...)` is gone as well: it re-stored a pointer that
was already in the tree, and mutating through it persists on its own, which is
how the rest of this realm already worked.

Ids stay plain integers and the rendered output of the storage port is
unchanged. Each port changes something `v0` promised, one the rendered output
and one the storage layout, so under this repo's versioning rule each is a
compatibility change and neither could be an edit to `v0` in place.

They land in the **same** new version because `v1` was never published. A
version number is a tag on something that exists on a chain, and until it does
there is nothing for a second number to avoid disturbing, so the right move is
to keep editing the version you have. `gnopm unbump` is what folded the second
port back down into this one.

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---

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:**

![gno.land/r/moul/x/daily/connect4/v1 dependency graph](https://raw.githubusercontent.com/moul/gno-contracts/main/_assets/gno.land/r/moul/x/daily/connect4/v1/deps.png)

> 🧪 **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).

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