1 files changed, 55 insertions, 0 deletions
diff --git a/lib/analysers/headers.ml b/lib/analysers/headers.ml
new file mode 100644
index 0000000..916dfee
--- /dev/null
+++ b/lib/analysers/headers.ml
@@ -0,0 +1,55 @@
+open StdLabels
+module I = ImportConf
+module E = ImportExpression.T
+module Syntax = ImportConf.Syntax
+module Table = ImportDataTypes.Table
+module Path = ImportDataTypes.Path
+
+module SheeetMap = Map.Make (struct
+  type t = Table.t
+
+  (** We are sure we can’t have the same name for two different table. *)
+  let compare v1 v2 = String.compare (Table.name v1) (Table.name v2)
+end)
+
+type content = string array
+
+type t = content SheeetMap.t
+(** The map associate a line of headers for each table. 
+
+    The header are always in string. *)
+
+(** Get the headers. The function has to be called after reading each document,
+    and will reformat the first line with the values from the cell. The
+    functions will not be evaluated (instead they will be displayed "as is".
+
+    When there is no value for this path, return empty string.
+ *)
+let columns : Syntax.t -> t -> string list =
+ fun conf t ->
+  (* We build here a custom printer which search in the array for the column
+     name.
+
+     This function will be given as argument in the expression printer. *)
+  let f : Path.t -> Buffer.t -> unit =
+   fun path b ->
+    let source = I.get_table_for_name conf path.alias in
+
+    match SheeetMap.find_opt source t with
+    | None -> ()
+    | Some arr -> (
+        try Buffer.add_string b (Array.get arr (path.column - 1)) with
+        | _ ->
+            prerr_endline
+            @@ Printf.sprintf "No header found for :%s.%s"
+                 (Option.value ~default:(I.root_table conf).Table.name
+                    path.alias)
+                 (ImportCSV.Csv.column_to_string path.column))
+  in
+
+  List.map conf.Syntax.columns ~f:(fun column ->
+      let b = Buffer.create 4 in
+
+      ImportExpression.Headers.headers_of_expression b f column;
+
+      Buffer.contents b)