diff --git a/src/lsp/cobol_indent/indent_main.ml b/src/lsp/cobol_indent/indent_main.ml
index a965fbbe7..507bab36b 100644
--- a/src/lsp/cobol_indent/indent_main.ml
+++ b/src/lsp/cobol_indent/indent_main.ml
@@ -23,7 +23,7 @@ let indent_range ~dialect ~source_format ~indent_config ~range ~filename ~conten
     Cobol_preproc.Src_format.from_config SFFixed
   in
   let state =
-    Cobol_preproc.Preprocess.fold_source_lines ~dialect ~source_format
+    Cobol_preproc.Main.fold_source_lines ~dialect ~source_format
       ~on_initial_source_format:(fun src_format st -> { st with src_format })
       ~on_compiler_directive:(fun _ { payload = cd;  _} st ->
         match cd with
diff --git a/src/lsp/cobol_lsp/document.ml b/src/lsp/cobol_lsp/document.ml
index e99e1b7d2..3f91a5dc1 100644
--- a/src/lsp/cobol_lsp/document.ml
+++ b/src/lsp/cobol_lsp/document.ml
@@ -72,7 +72,7 @@ let rewindable_parse ({ project; textdoc; _ } as doc) =
         recovery = EnableRecovery { silence_benign_recoveries = true };
         config = project.config.cobol_config;
       } @@
-  Cobol_preproc.Preprocess.preprocessor
+  Cobol_preproc.Main.preprocessor
     ~options:Cobol_preproc.Options.{
         default with
         libpath = Project.libpath_for ~uri:(uri doc) project;
@@ -116,7 +116,7 @@ let reparse_and_analyze ?position ({ copybook; rewinder; textdoc; _ } as doc) =
   | Some position, Some rewinder ->
       check doc @@
       Cobol_parser.Main.rewind_and_parse rewinder ~position @@
-      Cobol_preproc.Preprocess.reset_preprocessor_for_string @@
+      Cobol_preproc.Main.reset_preprocessor_for_string @@
       Lsp.Text_document.text textdoc
 
 (** Creates a record for a document that is not yet parsed or analyzed. *)
diff --git a/src/lsp/cobol_parser/main.ml b/src/lsp/cobol_parser/main.ml
index fea41c2c9..5be32258c 100644
--- a/src/lsp/cobol_parser/main.ml
+++ b/src/lsp/cobol_parser/main.ml
@@ -38,19 +38,19 @@ type 'x rewinder =
       ('x * ('x rewinder)) with_diags;
   }
 and preprocessor_rewind =
-  ?new_position: Lexing.position -> (Cobol_preproc.Preprocess.preprocessor as 'r) -> 'r
+  ?new_position: Lexing.position -> (Cobol_preproc.Main.preprocessor as 'r) -> 'r
 and position =
   | Lexing of Lexing.position
   | Indexed of { line: int; char: int }                  (* all starting at 0 *)
 
 type 'm simple_parsing
   = ?options:parser_options
-  -> Cobol_preproc.Preprocess.preprocessor
+  -> Cobol_preproc.Main.preprocessor
   -> (Cobol_ptree.Types.compilation_group option, 'm) output DIAGS.with_diags
 
 type 'm rewindable_parsing
   = ?options:parser_options
-  -> Cobol_preproc.Preprocess.preprocessor
+  -> Cobol_preproc.Main.preprocessor
   -> (((Cobol_ptree.Types.compilation_group option, 'm) output as 'x) *
       'x rewinder) DIAGS.with_diags
 
@@ -78,7 +78,7 @@ type 'm state =
     basis (mostly the pre-processor and tokenizer's states). *)
 and 'm preproc =
   {
-    pp: Cobol_preproc.Preprocess.t;               (* also holds diagnostics *)
+    pp: Cobol_preproc.Main.preprocessor;           (* also holds diagnostics *)
     tokzr: 'm Tokzr.state;
     persist: 'm persist;
   }
@@ -130,21 +130,21 @@ and update_tokzr ps tokzr =
   else { ps with preproc = { ps.preproc with tokzr } }
 
 let add_diag diag ({ preproc = { pp; _ }; _ } as ps) =
-  update_pp ps (Cobol_preproc.Preprocess.add_diag pp diag)
+  update_pp ps (Cobol_preproc.Main.add_diag pp diag)
 let add_diags diags ({ preproc = { pp; _ }; _ } as ps) =
-  update_pp ps (Cobol_preproc.Preprocess.add_diags pp diags)
+  update_pp ps (Cobol_preproc.Main.add_diags pp diags)
 
 let all_diags { preproc = { pp; tokzr; _ }; _ } =
-  DIAGS.Set.union (Cobol_preproc.Preprocess.diags pp) @@ Tokzr.diagnostics tokzr
+  DIAGS.Set.union (Cobol_preproc.Main.diags pp) @@ Tokzr.diagnostics tokzr
 
 (* --- *)
 
 let rec produce_tokens (ps: _ state as 's) : 's * Text_tokenizer.tokens =
-  let text, pp = Cobol_preproc.Preprocess.next_chunk ps.preproc.pp in
+  let text, pp = Cobol_preproc.Main.next_chunk ps.preproc.pp in
   let { preproc = { pp; tokzr; _ }; _ } as ps = update_pp ps pp in
   assert (text <> []);
   (* Note: this is the source format in use at the end of the sentence. *)
-  let source_format = Cobol_preproc.Preprocess.source_format pp in
+  let source_format = Cobol_preproc.Main.source_format pp in
   match Tokzr.tokenize_text ~source_format tokzr text with
   | Error `MissingInputs, tokzr ->
       produce_tokens (update_tokzr ps tokzr)
@@ -396,7 +396,7 @@ let on_exn ps e =
 let first_stage (ps: 'm state) ~make_checkpoint : ('a, 'm) stage =
   let ps, tokens = produce_tokens ps in
   let first_pos = match tokens with
-    | [] -> Cobol_preproc.Preprocess.position ps.preproc.pp
+    | [] -> Cobol_preproc.Main.position ps.preproc.pp
     | t :: _ -> Cobol_common.Srcloc.start_pos ~@t
   in
   normal ps tokens (make_checkpoint first_pos)
@@ -419,9 +419,9 @@ let aggregate_output (type m) (ps: m state) res
   | Eidetic ->
       let artifacts =
         { tokens = Tokzr.parsed_tokens ps.preproc.tokzr;
-          pplog = Cobol_preproc.Preprocess.rev_log ps.preproc.pp;
-          rev_comments = Cobol_preproc.Preprocess.rev_comments ps.preproc.pp;
-          rev_ignored = Cobol_preproc.Preprocess.rev_ignored ps.preproc.pp } in
+          pplog = Cobol_preproc.Main.rev_log ps.preproc.pp;
+          rev_comments = Cobol_preproc.Main.rev_comments ps.preproc.pp;
+          rev_ignored = Cobol_preproc.Main.rev_ignored ps.preproc.pp } in
       WithArtifacts (res, artifacts)
 
 (** Simple parsing *)
@@ -469,7 +469,7 @@ let init_rewindable_parse ps ~make_checkpoint =
 
 (** Stores a stage as part of the memorized rewindable history events. *)
 let save_interim_stage (ps, _, env) (store: _ rewindable_history) =
-  let preproc_position = Cobol_preproc.Preprocess.position ps.preproc.pp in
+  let preproc_position = Cobol_preproc.Main.position ps.preproc.pp in
   match store with
   | store'
     when preproc_position.pos_cnum <> preproc_position.pos_bol ->
@@ -516,7 +516,7 @@ let find_history_event_preceding ~position ({ store; _ } as rwps) =
         pos
     | Indexed { line; char } ->
         let ps = rewindable_parser_state rwps in
-        Cobol_preproc.Preprocess.position_at ~line ~char ps.preproc.pp
+        Cobol_preproc.Main.position_at ~line ~char ps.preproc.pp
   in
   let rec aux = function
     | [] ->
@@ -560,7 +560,7 @@ let rec rewind_n_parse
 
 let rewindable_parse
   : options:_ -> memory:'m memory -> make_checkpoint:_
-    -> Cobol_preproc.Preprocess.preprocessor
+    -> Cobol_preproc.Main.preprocessor
     -> ((('a option, 'm) output as 'x) * 'x rewinder) with_diags =
   fun ~options ~memory ~make_checkpoint pp ->
   let res, rwps =
@@ -581,7 +581,7 @@ let parse
     (type m)
     ~(memory: m memory)
     ?(options = Options.default)
-  : Cobol_preproc.Preprocess.t ->
+  : Cobol_preproc.Main.t ->
     (Cobol_ptree.Types.compilation_group option, m) output with_diags =
   parse_once ~options ~memory
     ~make_checkpoint:Grammar.Incremental.compilation_group
@@ -593,7 +593,7 @@ let rewindable_parse
     (type m)
     ~(memory: m memory)
     ?(options = Options.default)
-  : Cobol_preproc.Preprocess.t ->
+  : Cobol_preproc.Main.t ->
     (((Cobol_ptree.Types.compilation_group option, m) output as 'x) * 'x rewinder)
       with_diags =
   rewindable_parse ~options ~memory
diff --git a/src/lsp/cobol_parser/main.mli b/src/lsp/cobol_parser/main.mli
index 015c772d7..7fa5e18d0 100644
--- a/src/lsp/cobol_parser/main.mli
+++ b/src/lsp/cobol_parser/main.mli
@@ -37,7 +37,7 @@ open Outputs
 (** Simple parsing functions traverse the inputs once to produce a result. *)
 type 'm simple_parsing
   = ?options:Options.parser_options
-  -> Cobol_preproc.Preprocess.t
+  -> Cobol_preproc.Main.preprocessor
   -> (Cobol_ptree.Types.compilation_group option, 'm) output
     Cobol_common.Diagnostics.with_diags
 
@@ -60,7 +60,7 @@ val parse_with_artifacts
     {!rewinder} that may then be given to {!rewind_and_parse}. *)
 type 'm rewindable_parsing
   = ?options:parser_options
-  -> Cobol_preproc.Preprocess.preprocessor
+  -> Cobol_preproc.Main.preprocessor
   -> (((Cobol_ptree.Types.compilation_group option, 'm) output as 'x) * 'x rewinder)
     Cobol_common.Diagnostics.with_diags
 
@@ -74,7 +74,7 @@ and 'x rewinder
     of the input. *)
 and preprocessor_rewind =
   ?new_position:Lexing.position ->
-  (Cobol_preproc.Preprocess.t as 'r) -> 'r
+  (Cobol_preproc.Main.t as 'r) -> 'r
 
 (* val rewindable_parse *)
 (*   : memory:'m memory -> 'm rewindable_parsing *)
diff --git a/src/lsp/cobol_preproc/preprocess.ml b/src/lsp/cobol_preproc/main.ml
similarity index 100%
rename from src/lsp/cobol_preproc/preprocess.ml
rename to src/lsp/cobol_preproc/main.ml
diff --git a/src/lsp/cobol_preproc/preprocess.mli b/src/lsp/cobol_preproc/main.mli
similarity index 100%
rename from src/lsp/cobol_preproc/preprocess.mli
rename to src/lsp/cobol_preproc/main.mli
diff --git a/src/lsp/superbol_free_lib/command_pp.ml b/src/lsp/superbol_free_lib/command_pp.ml
index 2c4182f98..2651b0322 100644
--- a/src/lsp/superbol_free_lib/command_pp.ml
+++ b/src/lsp/superbol_free_lib/command_pp.ml
@@ -63,7 +63,7 @@ let cmd =
                          ~default:  common.preproc_options.source_format }
                    in
                    input |>
-                   Cobol_preproc.Preprocess.preprocessor ~options:preproc_options |>
+                   Cobol_preproc.Main.preprocessor ~options:preproc_options |>
                    Cobol_parser.Main.parse_simple ~options:common.parser_options
                  in
                  let my_text = Cobol_preproc.Src_input.from ~filename:file ~f:parse in
@@ -96,7 +96,7 @@ let cmd =
                  let text =
                    let common = common_get () in
                    Cobol_common.Diagnostics.show_n_forget @@
-                   Cobol_preproc.Preprocess.text_of_file file
+                   Cobol_preproc.Main.text_of_file file
                      ~options:common.preproc_options
                  in
                  let s =
diff --git a/test/cobol_parsing/parser_testing.ml b/test/cobol_parsing/parser_testing.ml
index fbf9eb373..9ad7b88d8 100644
--- a/test/cobol_parsing/parser_testing.ml
+++ b/test/cobol_parsing/parser_testing.ml
@@ -21,7 +21,7 @@ let preproc
   =
   Cobol_common.Srcloc.TESTING.register_file_contents ~filename contents;
   String { filename; contents } |>
-  Cobol_preproc.Preprocess.preprocessor
+  Cobol_preproc.Main.preprocessor
     ~options:Cobol_preproc.Options.{
         default with
         libpath = [];
@@ -149,7 +149,7 @@ let rewindable_parse
   =
   let DIAGS.{ result = Only ptree, rewinder; diags } =
     String { filename = "prog.cob"; contents = prog } |>
-    Cobol_preproc.Preprocess.preprocessor
+    Cobol_preproc.Main.preprocessor
       ~options:Cobol_preproc.Options.{
           verbose; libpath = []; source_format;
           config = Option.value config ~default:default.config;
@@ -198,7 +198,7 @@ let iteratively_append_chunks ?config ~f (prog, positions) =
       Pretty.(to_string "%S" @@ EzString.after prog (pos.cnum - 1));
     succ i,
     rewind_n_parse ~f:(f i num_chunks) rewinder pos
-      (Cobol_preproc.Preprocess.reset_preprocessor_for_string prog)
+      (Cobol_preproc.Main.reset_preprocessor_for_string prog)
   end (1, rewinder) (pairwise positions.pos_anonymous)
 
 
@@ -230,7 +230,7 @@ let iteratively_append_chunks_stuttering ?config ~f
       Pretty.(to_string "%S" @@ EzString.after prog (pos.cnum - 1));
     let rewinder =
       rewind_n_parse ~f:(f i num_chunks) rewinder pos
-        (Cobol_preproc.Preprocess.reset_preprocessor_for_string prog)
+        (Cobol_preproc.Main.reset_preprocessor_for_string prog)
     in
     let rewinder =
       if i < num_chunks then begin
@@ -241,7 +241,7 @@ let iteratively_append_chunks_stuttering ?config ~f
           Fmt.(truncated ~max:30)
           Pretty.(to_string "%S" @@ EzString.after prog' (pos.cnum - 1));
         rewind_n_parse ~f:(f i num_chunks) rewinder next_pos_1
-          (Cobol_preproc.Preprocess.reset_preprocessor_for_string prog')
+          (Cobol_preproc.Main.reset_preprocessor_for_string prog')
       end else rewinder
     in
     succ i, rewinder
@@ -280,13 +280,13 @@ let simulate_cut_n_paste ?config ~f0 ~f ?verbose ?(repeat = 1)
       and prog_suffix = EzString.after prog (next_pos.cnum - 1) in
       let rewinder =
         rewind_n_parse ~f:(fun _ _ -> ()) rewinder pos @@
-        Cobol_preproc.Preprocess.reset_preprocessor_for_string @@
+        Cobol_preproc.Main.reset_preprocessor_for_string @@
         prog_prefix ^ prog_suffix
       in
       Pretty.out "Putting it back@.";
       let rewinder =
         rewind_n_parse ~f:(f chunk_num num_chunks ~ptree0) rewinder pos @@
-        Cobol_preproc.Preprocess.reset_preprocessor_for_string prog
+        Cobol_preproc.Main.reset_preprocessor_for_string prog
       in
       loop (succ i) rewinder
     end
diff --git a/test/cobol_preprocessing/preproc_testing.ml b/test/cobol_preprocessing/preproc_testing.ml
index 48eaafd54..0e0b892f4 100644
--- a/test/cobol_preprocessing/preproc_testing.ml
+++ b/test/cobol_preprocessing/preproc_testing.ml
@@ -24,7 +24,7 @@ let preprocess
     ?(source_format = Cobol_config.Types.(SF SFFixed))
     contents =
   DIAGS.show_n_forget ~ppf:Fmt.stdout @@
-  Cobol_preproc.Preprocess.preprocess_input
+  Cobol_preproc.Main.preprocess_input
     ~options:Cobol_preproc.Options.{ default with verbose; libpath = [];
                                                   source_format } @@
   Cobol_preproc.Src_input.String { filename; contents }
@@ -36,7 +36,7 @@ let show_text
     contents =
   let text =
     DIAGS.show_n_forget ~ppf:Fmt.stdout @@
-    Cobol_preproc.Preprocess.text_of_input
+    Cobol_preproc.Main.text_of_input
       ~options:Cobol_preproc.Options.{ default with verbose; libpath = [];
                                                     source_format } @@
     Cobol_preproc.Src_input.String { filename; contents }
@@ -53,7 +53,7 @@ let show_source_lines
     contents
   =
   DIAGS.show_n_forget ~ppf:Fmt.stdout @@
-  Cobol_preproc.Preprocess.fold_source_lines ~dialect ~source_format
+  Cobol_preproc.Main.fold_source_lines ~dialect ~source_format
     ~f:begin fun lnum line () ->
       if with_line_numbers then Pretty.out "@\n%u: " lnum else Pretty.out "@\n";
       Pretty.out "%a" Cobol_preproc.Text.pp_text line;
@@ -71,10 +71,10 @@ let show_source_lines
     end
 
 let rec show_all_text pp =
-  match Cobol_preproc.Preprocess.next_chunk pp with
+  match Cobol_preproc.Main.next_chunk pp with
   | { payload = Cobol_preproc.Text.Eof; _ } :: _, _ ->
     Cobol_common.Diagnostics.Set.pp Fmt.stdout
-      (Cobol_preproc.Preprocess.diags pp);
+      (Cobol_preproc.Main.diags pp);
     pp
   | text, pp ->
     Pretty.out "%a@\n" Cobol_preproc.Text.pp_text text;
@@ -98,12 +98,12 @@ let preprocess_n_then_cut_n_paste_right_of_indicator
   Pretty.out "fixed: %a@." show_lines fixed_lines;
   Pretty.out " free: %a@." show_lines free_lines;
   Cobol_preproc.Src_input.string ~filename fixed_format_contents |>
-  Cobol_preproc.Preprocess.preprocessor
+  Cobol_preproc.Main.preprocessor
     ~options:Cobol_preproc.Options.{ default with verbose; libpath = [];
                                                   source_format } |>
   show_all_text |>
-  Cobol_preproc.Preprocess.reset_preprocessor_for_string free_format_contents |>
+  Cobol_preproc.Main.reset_preprocessor_for_string free_format_contents |>
   show_all_text |>
-  Cobol_preproc.Preprocess.reset_preprocessor_for_string fixed_format_contents |>
+  Cobol_preproc.Main.reset_preprocessor_for_string fixed_format_contents |>
   show_all_text |>
   ignore
diff --git a/test/output-tests/gnucobol.ml b/test/output-tests/gnucobol.ml
index 4a4251ba8..d2ba6d1a4 100644
--- a/test/output-tests/gnucobol.ml
+++ b/test/output-tests/gnucobol.ml
@@ -190,7 +190,7 @@ let do_check_parse (test_filename, contents, _, { check_loc;
   let source_format = guess_source_format ~filename ~command:check_command in
   let parse_simple input =
     input |>
-    Cobol_preproc.Preprocess.preprocessor
+    Cobol_preproc.Main.preprocessor
       ~options:Cobol_preproc.Options.{ default with source_format } |>
     Cobol_parser.Main.parse_simple
   in
diff --git a/test/output-tests/preproc.ml b/test/output-tests/preproc.ml
index 960476584..e509ee9ed 100644
--- a/test/output-tests/preproc.ml
+++ b/test/output-tests/preproc.ml
@@ -18,7 +18,7 @@ open Testsuite_utils
 
 let preprocess_file ~source_format ~config filename =
   Cobol_common.Diagnostics.show_n_forget ~min_level:Error @@
-  Cobol_preproc.Preprocess.preprocess_file filename
+  Cobol_preproc.Main.preprocess_file filename
     ~options:Cobol_preproc.Options.{ source_format; config;
                                      verbose = false; libpath = [] }
     ~ppf:std_formatter
diff --git a/test/output-tests/reparse.ml b/test/output-tests/reparse.ml
index 02cf9bfe2..bb1ef1b98 100644
--- a/test/output-tests/reparse.ml
+++ b/test/output-tests/reparse.ml
@@ -23,7 +23,7 @@ let reparse_file ~source_format ~config filename =
           default with
           recovery = DisableRecovery
         } @@
-    Cobol_preproc.Preprocess.preprocessor
+    Cobol_preproc.Main.preprocessor
       ~options:Cobol_preproc.Options.{
           default with
           libpath = [];