In --coq mode, qualify references to MenhirLib modules.

New options --coq-lib-path and --coq-lib-no-path control this behavior.

CHANGES.md

 # Changes
 
+## 2018/05/30
+
+* In `--coq` mode, Menhir now produces references to `MenhirLib.Grammar`
+  instead of just `Grammar`, and similarly for all modules in Menhir's support
+  library.
+
+* New command line option `--coq-lib-no-path` to suppress the above behavior
+  and retain the previous (now-deprecated) behavior, that is, produce
+  unqualified references the modules in Menhir's support library.
+
+* New command line option `--coq-lib-path <path>` to indicate under what name
+  (or path) the support library has been installed. Its default value is
+  `MenhirLib`.
+
 ## 2018/05/23
 
 * New commands `--infer-write-query`, `--infer-read-reply`, and

doc/macros.tex

@@ -160,6 +160,8 @@
 \newcommand{\ostdlib}{\oo{stdlib}}
 \newcommand{\oversion}{\oo{version}}
 \newcommand{\ocoq}{\oo{coq}}
+\newcommand{\ocoqlibpath}{\oo{coq-lib-path}}
+\newcommand{\ocoqlibnopath}{\oo{coq-lib-no-path}}
 \newcommand{\ocoqnocomplete}{\oo{coq-no-complete}}
 \newcommand{\ocoqnoactions}{\oo{coq-no-actions}}
 \newcommand{\olisterrors}{\oo{list-errors}}

doc/manual.tex

@@ -130,6 +130,15 @@ irredundant. For more information, see \sref{sec:errors:new}.
 
 \docswitch{\ocoq} This switch causes \menhir to produce Coq code. See \sref{sec:coq}.
 
+\docswitch{\ocoqlibpath \nt{path}} This switch allows specifying under what name (or path) the Coq support library
+MenhirLib is known to Coq. When \menhir runs in \ocoq mode, the generated
+parser contains references to several modules in this library. This path is
+used to qualify these references. Its default value is \texttt{MenhirLib}.
+
+\docswitch{\ocoqlibnopath} This switch indicates that references to the Coq library MenhirLib
+should \emph{not} be qualified. This was the default behavior of \menhir prior to 2018/05/30.
+This switch is provided for compatibility, but normally should not be used.
+
 \docswitch{\ocoqnoactions} (Used in conjunction with \ocoq.) This switch
 causes the semantic actions present in the \vy file to be ignored and
 replaced with \verb+tt+, the unique inhabitant of Coq's \verb+unit+ type. This
@@ -3518,11 +3527,19 @@ named \verb+Parser.unambiguous+.
 % correspond bien à la fin du Stream.
 
 The parsers produced by \menhir's Coq back-end must be linked with a Coq
-library, which can be found in the CompCert tree~\cite{compcert,compcert-github}, in the
-\compcertgithubfile{cparser/validator}
-subdirectory. CompCert can be used as
+library. This library can be installed via the command \verb+opam install coq-menhirlib+.%
+%
+\footnote{This assumes that you have installed \texttt{opam}, the OCaml package manager,
+and that you have run the command \texttt{opam repo add coq-released
+https://coq.inria.fr/opam/released}.}
+%
+The Coq sources of this library can be found at
+\url{https://gitlab.inria.fr/fpottier/coq-menhirlib}.
+
+The CompCert verified compiler~\cite{compcert,compcert-github} can be used as
 an example if one wishes to use \menhir to generate a formally verified parser
-as part of some other project.
+as part of some other project. See in particular the directory
+\compcertgithubfile{cparser}.
 
 % fp: ce pourrait être bien de documenter les directives nécessaires pour
 % extraire du code efficace. D'après Xavier ce morceau de extraction.v

src/coqBackend.ml

@@ -451,8 +451,15 @@ module Run (T: sig end) = struct
     write_items f;
     fprintf f "End Aut.\n\n"
 
+  let from_menhirlib f =
+    match Settings.coq_lib_path with
+    | None ->
+        ()
+    | Some path ->
+        fprintf f "From %s " path
+
   let write_theorems f =
-    fprintf f "Require Import Main.\n\n";
+    from_menhirlib f; fprintf f "Require Import Main.\n\n";
 
     fprintf f "Module Parser := Main.Make Aut.\n";
 
@@ -503,13 +510,13 @@ module Run (T: sig end) = struct
       List.iter (fun s -> fprintf f "%s\n\n" s.Stretch.stretch_content)
         Front.grammar.UnparameterizedSyntax.preludes;
 
-    fprintf f "Require Import List.\n";
-    fprintf f "Require Import Int31.\n";
-    fprintf f "Require Import Syntax.\n";
-    fprintf f "Require Import Tuples.\n";
-    fprintf f "Require Import Alphabet.\n";
-    fprintf f "Require Grammar.\n";
-    fprintf f "Require Automaton.\n\n";
+    fprintf f "From Coq.Lists Require Import List.\n";
+    fprintf f "From Coq.Numbers.Cyclic.Int31 Require Import Int31.\n";
+    fprintf f "From Coq.Program Require Import Syntax.\n";
+    from_menhirlib f; fprintf f "Require Import Tuples.\n";
+    from_menhirlib f; fprintf f "Require Import Alphabet.\n";
+    from_menhirlib f; fprintf f "Require Grammar.\n";
+    from_menhirlib f; fprintf f "Require Automaton.\n\n";
     fprintf f "Unset Elimination Schemes.\n\n";
     write_grammar f;
     write_automaton f;

src/settings.ml

@@ -287,6 +287,9 @@ let set_echo_errors filename =
 let cmly =
   ref false
 
+let coq_lib_path =
+  ref (Some "MenhirLib")
+
 let options = Arg.align [
   "--base", Arg.Set_string base, "<basename> Specifies a base name for the output file(s)";
   "--canonical", Arg.Unit (fun () -> construction_mode := ModeCanonical), " Construct a canonical Knuth LR(1) automaton";
@@ -295,8 +298,10 @@ let options = Arg.align [
   "--compare-errors", Arg.String add_compare_errors, "<filename> (used twice) Compare two .messages files";
   "--compile-errors", Arg.String set_compile_errors, "<filename> Compile a .messages file to OCaml code";
   "--coq", Arg.Set coq, " Generate a formally verified parser, in Coq";
-  "--coq-no-complete", Arg.Set coq_no_complete, " Do not generate a proof of completeness";
+  "--coq-lib-path", Arg.String (fun path -> coq_lib_path := Some path), "<path> How to qualify references to MenhirLib";
+  "--coq-lib-no-path", Arg.Unit (fun () -> coq_lib_path := None), " Do *not* qualify references to MenhirLib";
   "--coq-no-actions", Arg.Set coq_no_actions, " Ignore semantic actions in the Coq output";
+  "--coq-no-complete", Arg.Set coq_no_complete, " Do not generate a proof of completeness";
   "--depend", Arg.Unit enable_depend, " Invoke ocamldep and display dependencies";
   "--dump", Arg.Set dump, " Write an .automaton file";
   "--echo-errors", Arg.String set_echo_errors, "<filename> Echo the sentences in a .messages file";
@@ -579,6 +584,9 @@ let echo_errors =
 let cmly =
   !cmly
 
+let coq_lib_path =
+  !coq_lib_path
+
 let infer =
   !infer
 

src/settings.mli

@@ -231,3 +231,9 @@ val echo_errors: string option
    binary-format description of the grammar and automaton. *)
 
 val cmly: bool
+
+(* This name is used in --coq mode. It appears in the generated Coq file,
+   and indicates under what name (or path) the Coq library MenhirLib is
+   known. Its default value is [Some "MenhirLib"]. *)
+
+val coq_lib_path: string option