gno.land/p/moul/x/daily/orderedmap/v0

Map that remembers insertion order — New, Set, Get, Has, Delete, Keys, Values, Iterate, At, Clone, Len, MaxKeys.

1import "gno.land/p/moul/x/daily/orderedmap/v0"
2
3o := orderedmap.New()
4o.Set("delta", "4"); o.Set("alpha", "1")
5o.Keys()             // ["delta" "alpha"] — insertion order, not sorted
6o.Set("delta", "99") // updates in place, keeps position

This matters more on chain than off it. gno map iteration order is unspecified, so a realm that ranges over a built-in map to build its Render can emit a different page on every call — a consensus bug, not a cosmetic one. This type gives back a deterministic order without requiring the keys to be sortable.

Semantics worth knowing, each with a test:

• Updating keeps position. Insertion order means first insertion, not last write.
• Re-inserting after a delete goes last — it is a new insertion.
• Keys returns a copy, so a caller cannot reorder the map through it.

Backed by a built-in map for O(1) Get plus a slice holding the order. Delete is O(n): closing the gap in that slice is what preserves order, and that trade is stated rather than hidden. MaxKeys (4096) bounds growth; a full map refuses new keys but still accepts updates to existing ones.

Live demo: r/moul/x/daily/orderedmapdemo · render it at /r/moul/x/daily/orderedmapdemo/v0.

Part of moul/gno-contracts — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

🧪 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.