1 files changed, 36 insertions, 33 deletions

diff --git a/lib/configuration/syntax.ml b/lib/configuration/syntax.ml
index 8efdc59..1eb3c70 100644
--- a/lib/configuration/syntax.ml
+++ b/lib/configuration/syntax.ml
@@ -13,46 +13,49 @@ let toml_of_table Table.{ file; tab; name } =
 
   Otoml.table values
 
-type extern = {
-  intern_key : Path.t E.t;
-  target : Table.t;
-  extern_key : Path.column E.t;
-  allow_missing : bool;
-  match_rule : string option;
-}
+module Extern = struct
+  type t = {
+    intern_key : Path.t E.t;
+    target : Table.t;
+    extern_key : Path.column E.t;
+    allow_missing : bool;
+    match_rule : string option;
+  }
+  (** Describe a relation beteween two tables *)
 
-let toml_of_extern extern =
-  let values =
-    [
-      ( "intern_key",
-        Otoml.string
-        @@ ImportExpression.Repr.repr ~top:true Path.repr extern.intern_key );
-      ( "extern_key",
-        Otoml.string
-        @@ ImportExpression.Repr.repr ~top:true
-             (fun v -> ":" ^ ImportCSV.Csv.column_to_string v)
-             extern.extern_key );
-      ("file", Otoml.string extern.target.file);
-      ("allow_missing", Otoml.boolean extern.allow_missing);
-    ]
-  in
+  let toml_of_extern extern =
+    let values =
+      [
+        ( "intern_key",
+          Otoml.string
+          @@ ImportExpression.Repr.repr ~top:true Path.repr extern.intern_key );
+        ( "extern_key",
+          Otoml.string
+          @@ ImportExpression.Repr.repr ~top:true
+               (fun v -> ":" ^ ImportCSV.Csv.column_to_string v)
+               extern.extern_key );
+        ("file", Otoml.string extern.target.file);
+        ("allow_missing", Otoml.boolean extern.allow_missing);
+      ]
+    in
 
-  let values =
-    match extern.target.tab with
-    | 1 -> values
-    | tab -> ("tab", Otoml.integer tab) :: values
-  in
+    let values =
+      match extern.target.tab with
+      | 1 -> values
+      | tab -> ("tab", Otoml.integer tab) :: values
+    in
 
-  Otoml.table values
+    Otoml.table values
 
-let toml_of_externs externs =
-  List.map externs ~f:(fun e -> (e.target.name, toml_of_extern e))
-  |> Otoml.table
+  let toml externs =
+    List.map externs ~f:(fun e -> (e.target.name, toml_of_extern e))
+    |> Otoml.table
+end
 
 type t = {
   version : int;
   source : Table.t;
-  externals : extern list;
+  externals : Extern.t list;
   columns : Path.t E.t list;
   filters : Path.t E.t list;
   sort : Path.t E.t list;
@@ -80,7 +83,7 @@ let repr t =
     [
       ("version", Otoml.integer t.version);
       ("source", toml_of_table t.source);
-      ("externals", toml_of_externs t.externals);
+      ("externals", Extern.toml t.externals);
       ("sheet", sheet);
     ]
   in