RNT interface

Co-authored-by: Estevan Castilho <tevo@riajuu.net>

1 files changed, 39 insertions, 0 deletions

diff --git a/lib/sublanguage_context.ml b/lib/sublanguage_context.ml
new file mode 100644
index 0000000..c7598f1
--- /dev/null
+++ b/lib/sublanguage_context.ml
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+(** Execution context passed to every sublanguage.
+
+    - [write_handle]   NT branch handle; sublanguages use it for mutations
+                       (create_relation, link_tuple, etc).  Read-only
+                       sublanguages (DRL) ignore it.
+
+    - [branch]         Structural view over the active branch — gives every
+                       executor random-access to every multigroup bound to
+                       the branch via [mg_of].  Schema lookups for an FQN
+                       [{mg; name}] use [branch#mg_of mg |> Option.bind
+                       (fun m -> m#get_relation name)].
+
+    - [resolve]        Builds an absolute RNT path for an FQN.  Pass
+                       [~branch:b] to address a relation on a different
+                       live branch (cross-multigroup reads).
+
+    - [switch_branch]  Closes the current branch and opens the named one,
+                       returning the delta describing the new branch's mg
+                       set.  Provided by the listener so VCL does not need
+                       direct access to session state. *)
+
+type branch_view = <
+  name           : string;
+  tip            : string;
+  mg_of          : string -> Management.Multigroup.multigroup option;
+  multigroups    : (string * Management.Multigroup.multigroup) list;
+  add_multigroup : name:string -> unit;
+  set_mg         : name:string ->
+                   Management.Multigroup.multigroup -> unit;
+  path           : ?branch:string -> Qualified_name.t -> string;
+>
+
+type t = {
+  write_handle  : Nt.branch_handle;
+  branch        : branch_view;
+  resolve       : ?branch:string -> Qualified_name.t -> string;
+  switch_branch : string ->
+                  (Sublanguage_types.transition_delta, Nt.error) result;
+}