Declarations.mli: reorganization of modular structures

 The earlier type [struct_expr_body] was far too broad,
 leading to code with unclear invariants, many "assert false", etc etc.
 Its replacement [module_alg_expr] has only three constructors:
   * MEident
   * MEapply : note the module_path as 2nd arg, no more constraints here
   * MEwith : no more constant_body inside, constr is just fine
 But no more SEBfunctor or SEBstruct constructor here (see below).
 This way, this datatype corresponds to algebraic expressions,
 i.e. anything that can appear in non-interactive modules.
 In fact, it even coincides now with [Entries.module_struct_entry].

 - Functor constructors are now necessarily on top of other
   structures thanks to a generic [functorize] datatype.

 - Structures are now separated from algebraic expressions by design :
   the [mod_type] and [typ_expr] fields now only contain structures
   (or functorized structures), while [mod_type_alg] and [typ_expr_alg]
   are restricted to algebraic expressions only.

 - Only the implementation field [mod_expr] could be either algebraic
   or structural. We handle this via a specialized datatype
   [module_implementation] with four constructors:

    * Abstract : no implementation (cf. for instance Declare Module)
    * Algebraic(_) : for non-interactive modules, e.g. Module M := N.
    * Struct(_) : for interactive module, e.g. Module M : T. ... End M.
    * FullStruct : for interactive module with no type restriction.

   The [FullStruct] is a particular case of [Struct] where the implementation
   need not be stored at all, since it is exactly equal to its expanded
   type present in [mod_type]. This is less fragile than hoping as earlier
   that pointer equality between [mod_type] and [mod_expr] will be
   preserved...

 - We clearly emphasize that only [mod_type] and [typ_expr] are
   relevant for the kernel, while [mod_type_alg] and [typ_expr_alg]
   are there only for a nicer extraction and shorter module printing.
   [mod_expr] is also not accessed by the kernel, but it is important
   for Print Assumptions later.

 - A few implicit invariants remain, for instance "no MEwith in mod_expr",
   see the final comment in Declarations

 - Heavy refactoring of module-related files : modops, mod_typing,
   safe_typing, declaremods, extraction/extract_env.ml ...

 - Coqchk has been adapted accordingly. The code concerning MEwith
   in Mod_checking is now gone, since we cannot have any in mod_expr.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16712 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 7 insertions, 7 deletions

diff --git a/toplevel/himsg.ml b/toplevel/himsg.ml
index c9090f76e0..de77ee131c 100644
--- a/toplevel/himsg.ml
+++ b/toplevel/himsg.ml
@@ -671,8 +671,11 @@ let explain_label_already_declared l =
 let explain_application_to_not_path _ =
   str "Application of modules is restricted to paths."
 
-let explain_not_a_functor mtb =
-  str "Application of not a functor."
+let explain_not_a_functor () =
+  str "Application of a non-functor."
+
+let explain_is_a_functor () =
+  str "Illegal use of a functor."
 
 let explain_incompatible_module_types mexpr1 mexpr2 =
   str "Incompatible module types."
@@ -687,9 +690,6 @@ let explain_incompatible_labels l l' =
   str "Opening and closing labels are not the same: " ++
   str (Label.to_string l) ++ str " <> " ++ str (Label.to_string l') ++ str "!"
 
-let explain_signature_expected mtb =
-  str "Signature expected."
-
 let explain_not_a_module s =
   quote (str s) ++ str " is not a module."
 
@@ -719,12 +719,12 @@ let explain_module_error = function
   | SignatureMismatch (l,spec,err) -> explain_signature_mismatch l spec err
   | LabelAlreadyDeclared l -> explain_label_already_declared l
   | ApplicationToNotPath mexpr -> explain_application_to_not_path mexpr
-  | NotAFunctor mtb -> explain_not_a_functor mtb
+  | NotAFunctor -> explain_not_a_functor ()
+  | IsAFunctor -> explain_is_a_functor ()
   | IncompatibleModuleTypes (m1,m2) -> explain_incompatible_module_types m1 m2
   | NotEqualModulePaths (mp1,mp2) -> explain_not_equal_module_paths mp1 mp2
   | NoSuchLabel l -> explain_no_such_label l
   | IncompatibleLabels (l1,l2) -> explain_incompatible_labels l1 l2
-  | SignatureExpected mtb -> explain_signature_expected mtb
   | NotAModule s -> explain_not_a_module s
   | NotAModuleType s -> explain_not_a_module_type s
   | NotAConstant l -> explain_not_a_constant l