[api] Make `vernac/` self-contained.

We make the vernacular implementation self-contained in the `vernac/`
directory. To this extent we relocate the parser, printer, and AST to
the `vernac/` directory, and move a couple of hint-related types to
`Hints`, where they do indeed belong.

IMO this makes the code easier to understand, and provides a better
modularity of the codebase as now all things under `tactics` have 0
knowledge about vernaculars.

The vernacular extension machinery has also been moved to `vernac/`,
this will help when #6171 [proof state cleanup] is completed along
with a stronger typing for vernacular interpretation that can
distinguish different types of effects vernacular commands can perform.

This PR introduces some very minor source-level incompatibilities due
to a different module layering [thus deprecating is not
possible]. Impact should be relatively minor.

1 files changed, 56 insertions, 0 deletions

diff --git a/vernac/pvernac.ml b/vernac/pvernac.ml
new file mode 100644
index 000000000..bac882381
--- /dev/null
+++ b/vernac/pvernac.ml
@@ -0,0 +1,56 @@
+(************************************************************************)
+(*         *   The Coq Proof Assistant / The Coq Development Team       *)
+(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
+(* <O___,, *       (see CREDITS file for the list of authors)           *)
+(*   \VV/  **************************************************************)
+(*    //   *    This file is distributed under the terms of the         *)
+(*         *     GNU Lesser General Public License Version 2.1          *)
+(*         *     (see LICENSE file for the text of the license)         *)
+(************************************************************************)
+
+open Pcoq
+
+let uncurry f (x,y) = f x y
+
+let uvernac = create_universe "vernac"
+
+module Vernac_ =
+  struct
+    let gec_vernac s = Gram.entry_create ("vernac:" ^ s)
+
+    (* The different kinds of vernacular commands *)
+    let gallina = gec_vernac "gallina"
+    let gallina_ext = gec_vernac "gallina_ext"
+    let command = gec_vernac "command"
+    let syntax = gec_vernac "syntax_command"
+    let vernac_control = gec_vernac "Vernac.vernac_control"
+    let rec_definition = gec_vernac "Vernac.rec_definition"
+    let red_expr = new_entry utactic "red_expr"
+    let hint_info = gec_vernac "hint_info"
+    (* Main vernac entry *)
+    let main_entry = Gram.entry_create "vernac"
+    let noedit_mode = gec_vernac "noedit_command"
+
+    let () =
+      let act_vernac = Gram.action (fun v loc -> Some (to_coqloc loc, v)) in
+      let act_eoi = Gram.action (fun _ loc -> None) in
+      let rule = [
+        ([ Symbols.stoken Tok.EOI ], act_eoi);
+        ([ Symbols.snterm (Gram.Entry.obj vernac_control) ], act_vernac );
+      ] in
+      uncurry (Gram.extend main_entry) (None, [None, None, rule])
+
+    let command_entry_ref = ref noedit_mode
+    let command_entry =
+      Gram.Entry.of_parser "command_entry"
+        (fun strm -> Gram.parse_tokens_after_filter !command_entry_ref strm)
+
+  end
+
+let main_entry = Vernac_.main_entry
+
+let set_command_entry e = Vernac_.command_entry_ref := e
+let get_command_entry () = !Vernac_.command_entry_ref
+
+let () =
+  register_grammar Stdarg.wit_red_expr (Vernac_.red_expr);