/p/moul/x/daily/flatmap/v0

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`gno.land/p/moul/x/daily/flatmap/v0`

Sorted-vector map — New, Set, Get, Has, Delete, Keys, Values, At, Iterate, Range, Clone, Sorted, MaxEntries.

1import "gno.land/p/moul/x/daily/flatmap/v0"
2
3f := flatmap.New()
4f.Set("delta", "4"); f.Set("alpha", "1")
5f.Keys()                  // ["alpha" "delta"] — sorted by construction
6f.At(0)                   // "alpha", "1", true — indexed access
7f.Range("a", "c", fn)     // lo inclusive, hi exclusive

The STL flat_map trade. Keys and values live in two parallel sorted slices instead of a hash table or a tree of nodes:

operation	cost
`Get`	O(log n) binary search over contiguous memory
iteration	O(n), already ordered, nothing to sort
`Set` in the middle	O(n) — the tail shifts
`Set` at the end	O(1) amortised — the fast path

Cheap reads and cheap ordered iteration, paid for at write time. That trade is stated rather than hidden.

On chain the ordering is the real draw: a built-in gno map iterates in an unspecified order, so a Render built from one can differ between nodes. A flat map is sorted by construction, so iteration is deterministic without a sort on every read.

Sorted storage also buys two things a hash map cannot offer: At(i) positional access, and Range(lo, hi) as two binary searches and a walk — including when the bounds are not themselves keys.

Sorted() is exported so callers can assert the invariant; it holds through the whole public API, including 200 worst-case head insertions.

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