From e9bc4aa3fa0e775acf1978722da1fde1ed8a469d Mon Sep 17 00:00:00 2001
From: Marcos Magueta <maguetamarcos@gmail.com>
Date: Sat, 7 Mar 2026 02:40:26 -0300
Subject: erlang port commands and generated tests

---
 lib/merkle.ml | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 lib/merkle.ml

(limited to 'lib/merkle.ml')

diff --git a/lib/merkle.ml b/lib/merkle.ml
new file mode 100644
index 0000000..e3f68d9
--- /dev/null
+++ b/lib/merkle.ml
@@ -0,0 +1,71 @@
+(** Merkle tree module signature for content-addressed hash sets.
+
+    This is an opaque interface that can be backed by different implementations:
+    - A simple hash set (current placeholder)
+    - A proper radix/patricia merkle tree (e.g., plebeia when OCaml 5 support arrives)
+
+    The tree stores hashes as keys (like a set) and computes a root hash
+    from all contained elements. *)
+
+module type S = sig
+  type t
+
+  (** The empty tree *)
+  val empty : t
+
+  (** Check if tree is empty *)
+  val is_empty : t -> bool
+
+  (** Insert a hash into the tree. Returns a new tree. *)
+  val insert : Conventions.Hash.t -> t -> t
+
+  (** Delete a hash from the tree. Returns a new tree. *)
+  val delete : Conventions.Hash.t -> t -> t
+
+  (** Check if a hash is in the tree *)
+  val member : Conventions.Hash.t -> t -> bool
+
+  (** Get all hashes in the tree *)
+  val keys : t -> Conventions.Hash.t list
+
+  (** Compute the root hash of the tree. None if empty. *)
+  val root_hash : t -> Conventions.Hash.t option
+
+  (** Number of elements in the tree *)
+  val size : t -> int
+end
+
+(** Simple hash set implementation.
+    This is a placeholder until a proper radix-merkle library
+    with OCaml 5 support becomes available. *)
+module HashSet : S = struct
+  module StringSet = Set.Make(String)
+
+  type t = StringSet.t
+
+  let empty = StringSet.empty
+
+  let is_empty = StringSet.is_empty
+
+  let insert hash tree = StringSet.add hash tree
+
+  let delete hash tree = StringSet.remove hash tree
+
+  let member hash tree = StringSet.mem hash tree
+
+  let keys tree = StringSet.elements tree
+
+  let root_hash tree =
+    if StringSet.is_empty tree then
+      None
+    else
+      (* Compute root hash by hashing sorted concatenation of all hashes *)
+      let sorted_hashes = StringSet.elements tree in
+      let concatenated = String.concat "" sorted_hashes in
+      Some (Conventions.Hash.hash_text concatenated)
+
+  let size = StringSet.cardinal
+end
+
+(** Default implementation using HashSet *)
+include HashSet
-- 
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