Added a magic cookie, which is checked at link time, ensuring that

a parser produced by menhir --table cannot be linked with an incorrect
version of MenhirLib.

CHANGES

+2015/11/11:
+The code produced by version XXXXXXXX of menhir --table can now be linked only
+against a matching version of MenhirLib. If an incorrect version of MenhirLib
+is installed, the OCaml compiler should complain that
+[MenhirLib.StaticVersion.require_XXXXXXXX] is undefined.
+
 2015/11/10:
 Optimized the computation of $symbolstartpos, based on a couple of assumptions
 about the lexer. (See the manual.)

GNUmakefile

@@ -112,10 +112,12 @@ package: clean
 	    $(HEADACHE) -h $(LIBHEAD) $$file ; \
 	  done
 # Set the version number into the files that mention it. These
-# include version.ml, version.tex, META.
+# include version.ml, StaticVersion.{ml,mli}, version.tex, META.
 	@ echo "-> Setting version to $(DATE)."
 	@ echo let version = \"$(DATE)\" > $(PACKAGE)/src/version.ml
 	@ echo version = \"$(DATE)\" >> $(PACKAGE)/src/META
+	@ echo "let require_$(DATE) = ()" > $(PACKAGE)/src/StaticVersion.ml
+	@ echo "val require_$(DATE) : unit" > $(PACKAGE)/src/StaticVersion.mli
 # Copy and compile the documentation.
 	@ echo "-> Generating the documentation."
 	@ cp -r doc $(PACKAGE)

TODO

-* Add a magic number to detect inconsistencies between Menhir and MenhirLib?
-
 * Look for "artificial dependency" and remove them.
   Make sure every module is explicitly called.
 

src/StaticVersion.ml

+(* This file is overwritten when a package is created. It is supposed
+   to define a value of type [unit] whose name is [require_XXXXXXXX],
+   where [XXXXXXXX] is our 8-digit version number. *)
+
+let require_unreleased =
+  ()

src/StaticVersion.mli

+(* This file is overwritten when a package is created. It is supposed
+   to define a value of type [unit] whose name is [require_XXXXXXXX],
+   where [XXXXXXXX] is our 8-digit version number. *)
+
+val require_unreleased: unit
+

src/menhirLib.mlpack

@@ -15,3 +15,4 @@ TableFormat
 InspectionTableFormat
 InspectionTableInterpreter
 TableInterpreter
+StaticVersion

src/tableBackend.ml

@@ -58,6 +58,9 @@ let entry =
 let start =
   interpreter ^ ".start"
 
+let staticVersion =
+  menhirlib ^ ".StaticVersion"
+
 (* The following are names of internal sub-modules. *)
 
 let basics =
@@ -949,6 +952,19 @@ let first () =
 
 (* ------------------------------------------------------------------------ *)
 
+(* A reference to [MenhirLib.StaticVersion.require_XXXXXXXX], where [XXXXXXXX]
+   is our 8-digit version number. This ensures that the generated code can be
+   linked only with an appropriate version of MenhirLib. This is important
+   because we use unsafe casts, and a version mismatch could cause a crash. *)
+
+let versiondef = {
+  valpublic = true;
+  valpat = PUnit;
+  valval = EVar (staticVersion ^ ".require_" ^ Version.version);
+}
+
+(* ------------------------------------------------------------------------ *)
+
 (* Let's put everything together. *)
 
 open UnparameterizedSyntax
@@ -960,6 +976,15 @@ let program =
  
   [ SIFunctor (grammar.parameters,
 
+    (* Make a reference to [MenhirLib.StaticVersion.require_XXXXXXXX], where
+       [XXXXXXXX] is our 8-digit version number. This ensures that the
+       generated code can be linked only with an appropriate version of
+       MenhirLib. This is important because we use unsafe casts, and a
+       version mismatch could cause a crash. *)
+
+    SIComment "This generated code requires the following version of MenhirLib:" ::
+    SIValDefs (false, [ versiondef ]) ::
+
     (* Define the internal sub-module [basics], which contains the definitions
        of the exception [Error] and of the type [token]. Then, include this
        sub-module. This sub-module is used again below, as part of the

src/version.ml

+(* This file is overwritten when a package is created. The version
+   string is defined as an 8-digit version number [XXXXXXXX]. *)
+
+(* During development, [version] is defined as ["unreleased"]. This
+   must match the name of the variable [version_unreleased] in the
+   module [StaticVersion]. *)
+
 let version =
-  "<unreleased>" (* to be overridden when a package is created *)
+  "unreleased"