From aa26a6d2b15f2a1315fffb2fec9ea7c8b4ef81f1 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 16:07:14 +0200
Subject: [PATCH 01/16] fix (app modules) usage in (ice-9 session)

* module/ice-9/session.scm (root-modules): Fix '(app modules) usage.
---
 module/ice-9/session.scm | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/module/ice-9/session.scm b/module/ice-9/session.scm
index f3c8f6625..10ce61396 100644
--- a/module/ice-9/session.scm
+++ b/module/ice-9/session.scm
@@ -404,8 +404,7 @@ It is an image under the mapping EXTRACT."
 		     identity))
 
 (define (root-modules)
-  (cons the-root-module
-	(submodules (nested-ref the-root-module '(app modules)))))
+  (submodules (resolve-module '() #f)))
 
 (define (submodules m)
   (hash-fold (lambda (name var data)

From 51b22dbb48b51303e0a2f8d3fa2b87e703736feb Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:34:22 +0200
Subject: [PATCH 02/16] tweak to resolve-module

* module/ice-9/boot-9.scm (resolve-module): If we found a module but it
  didn't have a public interface and we're not autoloading, just return
  the module directly instead of dispatching to make-modules-in.
---
 module/ice-9/boot-9.scm | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 6a36ea4a0..9f9a9d391 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2360,10 +2360,10 @@ If there is no handler at all, Guile prints an error and then exits."
           (try-load-module name version)
           (resolve-module name #f))
          (else
-          ;; A module is not bound (but maybe something else is),
-          ;; we're not autoloading -- here's the weird semantics,
-          ;; we create an empty module.
-          (make-modules-in root name)))))))
+          ;; No module found (or if one was, it had no public interface), and
+          ;; we're not autoloading. Here's the weird semantics: we ensure
+          ;; there's an empty module.
+          (or already (make-modules-in root name))))))))
 
 
 (define (try-load-module name version)

From 0f27ab8a9e10ccb014a0bfc7fcc984d8d1bf124b Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:37:36 +0200
Subject: [PATCH 03/16] add module-ref-submodule, module-define-submodule!

* module/ice-9/boot-9.scm (module-ref-submodule):
  (module-define-submodule!): New stubs, will be used to separate
  traversing the module tree from accessing values.
---
 module/ice-9/boot-9.scm | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 9f9a9d391..5f2da30c3 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1916,6 +1916,20 @@ If there is no handler at all, Guile prints an error and then exits."
 (define (module-map proc module)
   (hash-map->list proc (module-obarray module)))
 
+;; Submodules
+;;
+;; Modules exist in a separate namespace from values, because you generally do
+;; not want the name of a submodule, which you might not even use, to collide
+;; with local variables that happen to be named the same as the submodule.
+;;
+(define (module-ref-submodule module name)
+  (let ((m (module-ref module name)))
+    (and m (module? m) m)))
+
+(define (module-define-submodule! module name submodule)
+  (module-define! module name submodule))
+
+
 
 
 ;;; {Low Level Bootstrapping}

From b910c4ac4ec8c66d1c6495ae958fd76641a32e53 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:41:34 +0200
Subject: [PATCH 04/16] nested-ref et al use module-ref-submodule; add -module
 nested variants

* module/ice-9/boot-9.scm: Update comments above nested-ref to include
  ref-module and define-module!.
  (nested-ref, nested-set!, nested-define!, nested-remove!): Use
  module-ref-submodule to traverse the module hierarchy.
  (nested-ref-module, nested-define-module!): New functions, like
  nested-ref and nested-define!, but operate on namespaces instead of
  values.
  (local-ref-module, local-define-module): New analogs of local-ref and
  local-define, but for namespaces.
---
 module/ice-9/boot-9.scm | 108 ++++++++++++++++++++++++++++++----------
 1 file changed, 81 insertions(+), 27 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 5f2da30c3..9fef3a795 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2084,15 +2084,15 @@ If there is no handler at all, Guile prints an error and then exits."
 ;;; {Recursive Namespaces}
 ;;;
 ;;; A hierarchical namespace emerges if we consider some module to be
-;;; root, and variables bound to modules as nested namespaces.
+;;; root, and submodules of that module to be nested namespaces.
 ;;;
-;;; The routines in this file manage variable names in hierarchical namespace.
+;;; The routines here manage variable names in hierarchical namespace.
 ;;; Each variable name is a list of elements, looked up in successively nested
 ;;; modules.
 ;;;
 ;;;             (nested-ref some-root-module '(foo bar baz))
-;;;             => <value of a variable named baz in the module bound to bar in
-;;;                 the module bound to foo in some-root-module>
+;;;             => <value of a variable named baz in the submodule bar of
+;;;                 the submodule foo of some-root-module>
 ;;;
 ;;;
 ;;; There are:
@@ -2105,50 +2105,104 @@ If there is no handler at all, Guile prints an error and then exits."
 ;;;     nested-define! a-root name val
 ;;;     nested-remove! a-root name
 ;;;
+;;; These functions manipulate values in namespaces. For referencing the
+;;; namespaces themselves, use the following:
 ;;;
-;;; (current-module) is a natural choice for a-root so for convenience there are
+;;;     nested-ref-module a-root name
+;;;     nested-define-module! a-root name mod
+;;;
+;;; (current-module) is a natural choice for a root so for convenience there are
 ;;; also:
 ;;;
-;;;     local-ref name          ==      nested-ref (current-module) name
-;;;     local-set! name val     ==      nested-set! (current-module) name val
-;;;     local-define name val   ==      nested-define! (current-module) name val
-;;;     local-remove name       ==      nested-remove! (current-module) name
+;;;     local-ref name                ==  nested-ref (current-module) name
+;;;     local-set! name val           ==  nested-set! (current-module) name val
+;;;     local-define name val         ==  nested-define! (current-module) name val
+;;;     local-remove name             ==  nested-remove! (current-module) name
+;;;     local-ref-module name         ==  nested-ref-module (current-module) name
+;;;     local-define-module! name m   ==  nested-define-module! (current-module) name m
 ;;;
 
 
 (define (nested-ref root names)
-  (let loop ((cur root)
-             (elts names))
-    (cond
-     ((null? elts)              cur)
-     ((not (module? cur))       #f)
-     (else (loop (module-ref cur (car elts) #f) (cdr elts))))))
+  (if (null? names)
+      root
+      (let loop ((cur root)
+                 (head (car names))
+                 (tail (cdr names)))
+        (if (null? tail)
+            (module-ref cur head #f)
+            (let ((cur (module-ref-submodule cur head)))
+              (and cur
+                   (loop cur (car tail) (cdr tail))))))))
 
 (define (nested-set! root names val)
   (let loop ((cur root)
-             (elts names))
-    (if (null? (cdr elts))
-        (module-set! cur (car elts) val)
-        (loop (module-ref cur (car elts)) (cdr elts)))))
+             (head (car names))
+             (tail (cdr names)))
+    (if (null? tail)
+        (module-set! cur head val)
+        (let ((cur (module-ref-submodule cur head)))
+          (if (not cur)
+              (error "failed to resolve module" names)
+              (loop cur (car tail) (cdr tail)))))))
 
 (define (nested-define! root names val)
   (let loop ((cur root)
-             (elts names))
-    (if (null? (cdr elts))
-        (module-define! cur (car elts) val)
-        (loop (module-ref cur (car elts)) (cdr elts)))))
+             (head (car names))
+             (tail (cdr names)))
+    (if (null? tail)
+        (module-define! cur head val)
+        (let ((cur (module-ref-submodule cur head)))
+          (if (not cur)
+              (error "failed to resolve module" names)
+              (loop cur (car tail) (cdr tail)))))))
 
 (define (nested-remove! root names)
   (let loop ((cur root)
-             (elts names))
-    (if (null? (cdr elts))
-        (module-remove! cur (car elts))
-        (loop (module-ref cur (car elts)) (cdr elts)))))
+             (head (car names))
+             (tail (cdr names)))
+    (if (null? tail)
+        (module-remove! cur head)
+        (let ((cur (module-ref-submodule cur head)))
+          (if (not cur)
+              (error "failed to resolve module" names)
+              (loop cur (car tail) (cdr tail)))))))
+
+
+(define (nested-ref-module root names)
+  (let loop ((cur root)
+             (names names))
+    (if (null? names)
+        cur
+        (let ((cur (module-ref-submodule cur (car names))))
+          (and cur
+               (loop cur (cdr names)))))))
+
+(define (nested-define-module! root names module)
+  (if (null? names)
+      (error "can't redefine root module" root module)
+      (let loop ((cur root)
+                 (head (car names))
+                 (tail (cdr names)))
+        (if (null? tail)
+            (module-define-submodule! cur head module)
+            (let ((cur (or (module-ref-submodule cur head)
+                           (let ((m (make-module 31)))
+                             (set-module-kind! m 'directory)
+                             (set-module-name! m (append (module-name cur)
+                                                         (list head)))
+                             (module-define-submodule! cur head m)
+                             m))))
+              (loop cur (car tail) (cdr tail)))))))
+
 
 (define (local-ref names) (nested-ref (current-module) names))
 (define (local-set! names val) (nested-set! (current-module) names val))
 (define (local-define names val) (nested-define! (current-module) names val))
 (define (local-remove names) (nested-remove! (current-module) names))
+(define (local-ref-module names) (nested-ref-module (current-module) names))
+(define (local-define-module names mod) (nested-define-module! (current-module) names mod))
+
 
 
 

From 9e0bfdbaa39ff87e002ec5bbf7183de4ce8f6b61 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:44:31 +0200
Subject: [PATCH 05/16] use the define-module variants in module-name and
 make-modules-in

* module/ice-9/boot-9.scm (module-name): Use module-define-submodule!
  instead of nested-define!.
  (make-modules-in): Rewrite in terms of nested-define-module!.
---
 module/ice-9/boot-9.scm | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 9fef3a795..b6b077c6c 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2267,24 +2267,16 @@ If there is no handler at all, Guile prints an error and then exits."
             ;; `resolve-module'. This is important as `psyntax' stores module
             ;; names and relies on being able to `resolve-module' them.
             (set-module-name! mod name)
-            (nested-define! (resolve-module '() #f) name mod)
+            (nested-define-module! (resolve-module '() #f) name mod)
             (accessor mod))))))
 
 (define (make-modules-in module name)
-  (if (null? name)
-      module
-      (make-modules-in
-       (let* ((var (module-local-variable module (car name)))
-              (val (and var (variable-bound? var) (variable-ref var))))
-         (if (module? val)
-             val
-             (let ((m (make-module 31)))
-               (set-module-kind! m 'directory)
-               (set-module-name! m (append (module-name module)
-                                           (list (car name))))
-               (module-define! module (car name) m)
-               m)))
-       (cdr name))))
+  (or (nested-ref-module module name)
+      (let ((m (make-module 31)))
+        (set-module-kind! m 'directory)
+        (set-module-name! m (append (module-name module) name))
+        (nested-define-module! module name m)
+        m)))
 
 (define (beautify-user-module! module)
   (let ((interface (module-public-interface module)))

From d58ccc669cf796b8b9c579e86f3072f0f4223adf Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:55:32 +0200
Subject: [PATCH 06/16] resolve-module uses -module variants

* module/ice-9/boot-9.scm (resolve-module): Use module-define-submodule!
  when binding the root, and nested-ref-module for the hot lookup, which
  is guaranteed to return a module or #f.
---
 module/ice-9/boot-9.scm | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index b6b077c6c..5775c46b6 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2400,15 +2400,15 @@ If there is no handler at all, Guile prints an error and then exits."
   (let ((root (make-module)))
     (set-module-name! root '())
     ;; Define the-root-module as '(guile).
-    (module-define! root 'guile the-root-module)
+    (module-define-submodule! root 'guile the-root-module)
 
     (lambda (name . args) ;; #:optional (autoload #t) (version #f)
-      (let* ((already (nested-ref root name))
+      (let* ((already (nested-ref-module root name))
              (numargs (length args))
              (autoload (or (= numargs 0) (car args)))
              (version (and (> numargs 1) (cadr args))))
         (cond
-         ((and already (module? already)
+         ((and already
                (or (not autoload) (module-public-interface already)))
           ;; A hit, a palpable hit.
           (if (and version 

From 635a8b36b1dbed877fb8df752600870e9e1ee625 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 15:58:08 +0200
Subject: [PATCH 07/16] deprecated %app shims use module-define-submodule!

* module/ice-9/deprecated.scm (%app, app, modules): Don't use the module
  interface to provide %app shims, use module-define-submodule! directly
  to side-effect the root module.
---
 module/ice-9/deprecated.scm | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/module/ice-9/deprecated.scm b/module/ice-9/deprecated.scm
index 5c43b2f6b..2ea99ba23 100644
--- a/module/ice-9/deprecated.scm
+++ b/module/ice-9/deprecated.scm
@@ -38,9 +38,8 @@
             $tanh
             closure?
             %nil
-            @bind
-            %app
-            app))
+            @bind))
+
 
 ;;;; Deprecated definitions.
 
@@ -299,10 +298,12 @@
                    (lambda ()
                      (set! id old-v) ...)))))))))
 
-;; Define (%app modules)
-(define %app (make-module 31))
-(set-module-name! %app '(%app))
-(nested-define! %app '(modules) (resolve-module '() #f))
-
-;; app aliases %app
-(define app %app)
+;; Define (%app) and (%app modules), and have (app) alias (%app). This
+;; side-effects the-root-module, both to the submodules table and (through
+;; module-define-submodule! above) the obarray.
+;;
+(let ((%app (make-module 31)))
+  (set-module-name! %app '(%app))
+  (module-define-submodule! the-root-module '%app %app)
+  (module-define-submodule! the-root-module 'app %app)
+  (module-define-submodule! %app 'modules (resolve-module '() #f)))

From 28b8c785e7fbdc53045b32a896f4a730b29e050b Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 16:03:23 +0200
Subject: [PATCH 08/16] nested module fixen to (ice-9 ls)

* module/ice-9/ls.scm (local-definitions-in, definitions-in): Use nested
  module procedures, as appropriate.
  (recursive-local-define): Fix attempt to treat null as false. Whoops..
---
 module/ice-9/ls.scm | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/module/ice-9/ls.scm b/module/ice-9/ls.scm
index f729d58ce..6a5b4e09a 100644
--- a/module/ice-9/ls.scm
+++ b/module/ice-9/ls.scm
@@ -1,6 +1,6 @@
 ;;;; ls.scm --- functions for browsing modules
 ;;;;
-;;;; 	Copyright (C) 1995, 1996, 1997, 1999, 2001, 2006 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 1995, 1996, 1997, 1999, 2001, 2006, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -54,21 +54,19 @@
 ;;;		Analogous to `ls', but with local definitions only.
 
 (define (local-definitions-in root names)
-  (let ((m (nested-ref root names))
-	(answer '()))
-    (if (not (module? m))
-	(set! answer m)
-	(module-for-each (lambda (k v) (set! answer (cons k answer))) m))
-    answer))
+  (let ((m (nested-ref-module root names)))
+    (if m
+        (module-map (lambda (k v) k) m)
+        (nested-ref root names))))
 
 (define (definitions-in root names)
-  (let ((m (nested-ref root names)))
-    (if (not (module? m))
-	m
+  (let ((m (nested-ref-module root names)))
+    (if m
 	(reduce union
-		(cons (local-definitions-in m  '())
+		(cons (local-definitions-in m '())
 		      (map (lambda (m2) (definitions-in m2 '()))
-			   (module-uses m)))))))
+			   (module-uses m))))
+        (nested-ref root names))))
 
 (define (ls . various-refs)
   (if (pair? various-refs)
@@ -90,7 +88,7 @@
 
 (define (recursive-local-define name value)
   (let ((parent (reverse! (cdr (reverse name)))))
-    (and parent (make-modules-in (current-module) parent))
-    (local-define name value)))
+    (module-define! (make-modules-in (current-module) parent)
+                    name value)))
 
 ;;; ls.scm ends here

From 9b023f3c63f51ded3216de11c7f6126f02bacd8f Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 16:08:01 +0200
Subject: [PATCH 09/16] use nested-ref-module in (system xref)

* module/system/xref.scm (program-callee-rev-vars): Use
  nested-ref-module instead of nested-ref.
---
 module/system/xref.scm | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/module/system/xref.scm b/module/system/xref.scm
index 94ecb5bbf..acf5ed2f5 100644
--- a/module/system/xref.scm
+++ b/module/system/xref.scm
@@ -1,4 +1,4 @@
-;;;; 	Copyright (C) 2009 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2009, 2010 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -62,8 +62,8 @@
                            (lp (1+ i) (if v (cons-uniq v out) out))))
                         ((,mod ,sym ,public?)
                          ;; hm, hacky.
-                         (let* ((m (nested-ref the-root-module
-                                               (append '(%app modules) mod)))
+                         (let* ((m (nested-ref-module (resolve-module '() #f)
+                                                      mod))
                                 (v (and m
                                         (module-variable
                                          (if public?

From f905381d317d0e3edbcea55cdd05e29ba9e5cb20 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Thu, 22 Apr 2010 14:12:05 +0200
Subject: [PATCH 10/16] add submodules field to modules

* module/ice-9/boot-9.scm (module-type, module-constructor): Add a field
  to modules, a table that will hold submodules.
  (make-module, make-autoload-interface): Adapt.
---
 module/ice-9/boot-9.scm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 5775c46b6..ac00ece85 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1565,7 +1565,8 @@ If there is no handler at all, Guile prints an error and then exits."
      (import-obarray #:no-setter)
      observers
      (weak-observers #:no-setter)
-     version)))
+     version
+     submodules)))
 
 
 ;; make-module &opt size uses binder
@@ -1606,7 +1607,8 @@ If there is no handler at all, Guile prints an error and then exits."
                                           #f #f #f
                                           (make-hash-table %default-import-size)
                                           '()
-                                          (make-weak-key-hash-table 31) #f)))
+                                          (make-weak-key-hash-table 31) #f
+                                          (make-hash-table 7))))
 
           ;; We can't pass this as an argument to module-constructor,
           ;; because we need it to close over a pointer to the module
@@ -2680,7 +2682,8 @@ If there is no handler at all, Guile prints an error and then exits."
                           (set-car! autoload i)))
                     (module-local-variable i sym))))))
     (module-constructor (make-hash-table 0) '() b #f #f name 'autoload #f
-                        (make-hash-table 0) '() (make-weak-value-hash-table 31) #f)))
+                        (make-hash-table 0) '() (make-weak-value-hash-table 31) #f
+                        (make-hash-table 0))))
 
 (define (module-autoload! module . args)
   "Have @var{module} automatically load the module named @var{name} when one

From f6a5308b03f30872a1973a6d40116a636fa52b11 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 16:13:06 +0200
Subject: [PATCH 11/16] module-{ref,define}-submodule use the submodules table

* module/ice-9/boot-9.scm (module-ref-submodule)
  (module-define-submodule!): Implement in terms of the
  module-submodules table, instead of looking for bindings in the value
  namespace.

* module/ice-9/deprecated.scm (module-ref-submodule):
  (module-define-submodule!): Define deprecated versions of these that
  duplicate the submodules table in the normal values namespace, for
  back compatibility.
---
 module/ice-9/boot-9.scm     |  6 ++----
 module/ice-9/deprecated.scm | 20 +++++++++++++++++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index ac00ece85..bc9f170ca 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1925,12 +1925,10 @@ If there is no handler at all, Guile prints an error and then exits."
 ;; with local variables that happen to be named the same as the submodule.
 ;;
 (define (module-ref-submodule module name)
-  (let ((m (module-ref module name)))
-    (and m (module? m) m)))
+  (hashq-ref (module-submodules module) name))
 
 (define (module-define-submodule! module name submodule)
-  (module-define! module name submodule))
-
+  (hashq-set! (module-submodules module) name submodule))
 
 
 
diff --git a/module/ice-9/deprecated.scm b/module/ice-9/deprecated.scm
index 2ea99ba23..c6dab4e93 100644
--- a/module/ice-9/deprecated.scm
+++ b/module/ice-9/deprecated.scm
@@ -38,7 +38,9 @@
             $tanh
             closure?
             %nil
-            @bind))
+            @bind)
+
+  #:replace (module-ref-submodule module-define-submodule!))
 
 
 ;;;; Deprecated definitions.
@@ -298,6 +300,22 @@
                    (lambda ()
                      (set! id old-v) ...)))))))))
 
+(define (module-ref-submodule module name)
+  (or (hashq-ref (module-submodules module) name)
+      (let ((var (module-local-variable module name)))
+        (and (variable-bound? var)
+             (module? (variable-ref var))
+             (begin
+               (warn "module" module "not in submodules table")
+               (variable-ref var))))))
+
+(define (module-define-submodule! module name submodule)
+  (let ((var (module-local-variable module name)))
+    (if (and var (variable-bound? var) (not (module? (variable-ref var))))
+        (warn "defining module" module ": not overriding local definition" var)
+        (module-define! module name submodule)))
+  (hashq-set! (module-submodules module) name submodule))
+
 ;; Define (%app) and (%app modules), and have (app) alias (%app). This
 ;; side-effects the-root-module, both to the submodules table and (through
 ;; module-define-submodule! above) the obarray.

From 81fc66cfb665814d9cfd766b3c19be90ae1b13ec Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 16:31:09 +0200
Subject: [PATCH 12/16] add submodule binders

* module/ice-9/boot-9.scm (module-submodule-binder)
  (set-module-submodule-binder!): New field on modules.
  (make-module, make-autoload-interface): Adapt.
  (module-ref-submodule): If we miss the submodules table, call the
  submodules binder, if any.

* module/ice-9/deprecated.scm (module-ref-submodule): Check the
  submodule binder before the deprecated look into the obarray.
---
 module/ice-9/boot-9.scm     | 11 +++++++----
 module/ice-9/deprecated.scm |  2 ++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index bc9f170ca..3dcc8d90f 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1566,7 +1566,8 @@ If there is no handler at all, Guile prints an error and then exits."
      observers
      (weak-observers #:no-setter)
      version
-     submodules)))
+     submodules
+     submodule-binder)))
 
 
 ;; make-module &opt size uses binder
@@ -1608,7 +1609,7 @@ If there is no handler at all, Guile prints an error and then exits."
                                           (make-hash-table %default-import-size)
                                           '()
                                           (make-weak-key-hash-table 31) #f
-                                          (make-hash-table 7))))
+                                          (make-hash-table 7) #f)))
 
           ;; We can't pass this as an argument to module-constructor,
           ;; because we need it to close over a pointer to the module
@@ -1925,7 +1926,9 @@ If there is no handler at all, Guile prints an error and then exits."
 ;; with local variables that happen to be named the same as the submodule.
 ;;
 (define (module-ref-submodule module name)
-  (hashq-ref (module-submodules module) name))
+  (or (hashq-ref (module-submodules module) name)
+      (and (module-submodule-binder module)
+           ((module-submodule-binder module) module name))))
 
 (define (module-define-submodule! module name submodule)
   (hashq-set! (module-submodules module) name submodule))
@@ -2681,7 +2684,7 @@ If there is no handler at all, Guile prints an error and then exits."
                     (module-local-variable i sym))))))
     (module-constructor (make-hash-table 0) '() b #f #f name 'autoload #f
                         (make-hash-table 0) '() (make-weak-value-hash-table 31) #f
-                        (make-hash-table 0))))
+                        (make-hash-table 0) #f)))
 
 (define (module-autoload! module . args)
   "Have @var{module} automatically load the module named @var{name} when one
diff --git a/module/ice-9/deprecated.scm b/module/ice-9/deprecated.scm
index c6dab4e93..15e245d1a 100644
--- a/module/ice-9/deprecated.scm
+++ b/module/ice-9/deprecated.scm
@@ -302,6 +302,8 @@
 
 (define (module-ref-submodule module name)
   (or (hashq-ref (module-submodules module) name)
+      (and (module-submodule-binder module)
+           ((module-submodule-binder module) module name))
       (let ((var (module-local-variable module name)))
         (and (variable-bound? var)
              (module? (variable-ref var))

From 993dae8623e0fe6195000afb81902ea466bd2dc4 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 17:03:34 +0200
Subject: [PATCH 13/16] module-public-interface in Scheme

* libguile/modules.c: Consolidate all variables to the top of the file.
  (scm_module_public_interface): Dispatch to Scheme.
  (scm_post_boot_init_modules): Resolve module-public-interface.

* module/ice-9/boot-9.scm (module-public-interface): Implement in
  Scheme.
---
 libguile/modules.c      | 41 +++++++++++++----------------------------
 module/ice-9/boot-9.scm |  4 +++-
 2 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/libguile/modules.c b/libguile/modules.c
index ccb68b709..c8a4c2aa1 100644
--- a/libguile/modules.c
+++ b/libguile/modules.c
@@ -44,7 +44,16 @@ scm_t_bits scm_module_tag;
 
 static SCM the_module;
 
+static SCM module_make_local_var_x_var;
+
 static SCM the_root_module_var;
+static SCM process_define_module_var;
+static SCM process_use_modules_var;
+static SCM resolve_module_var;
+static SCM module_public_interface_var;
+static SCM module_export_x_var;
+static SCM default_duplicate_binding_procedures_var;
+
 
 static SCM unbound_variable (const char *func, SCM sym)
 {
@@ -149,10 +158,6 @@ convert_module_name (const char *name)
   return list;
 }
 
-static SCM process_define_module_var;
-static SCM process_use_modules_var;
-static SCM resolve_module_var;
-
 SCM
 scm_c_resolve_module (const char *name)
 {
@@ -183,8 +188,6 @@ scm_c_use_module (const char *name)
 	      scm_list_1 (scm_list_1 (convert_module_name (name))));
 }
 
-static SCM module_export_x_var;
-
 SCM
 scm_module_export (SCM module, SCM namelist)
 {
@@ -267,12 +270,6 @@ scm_lookup_closure_module (SCM proc)
  * release.
  */
 
-/* The `module-make-local-var!' variable.  */
-static SCM module_make_local_var_x_var = SCM_UNSPECIFIED;
-
-/* The `default-duplicate-binding-procedures' variable.  */
-static SCM default_duplicate_binding_procedures_var = SCM_UNSPECIFIED;
-
 /* Return the list of default duplicate binding handlers (procedures).  */
 static inline SCM
 default_duplicate_binding_handlers (void)
@@ -638,24 +635,11 @@ SCM_DEFINE (scm_module_import_interface, "module-import-interface", 2, 0, 0,
 }
 #undef FUNC_NAME
 
-SCM_SYMBOL (sym_sys_module_public_interface, "%module-public-interface");
-
-SCM_DEFINE (scm_module_public_interface, "module-public-interface", 1, 0, 0,
-	    (SCM module),
-	    "Return the public interface of @var{module}.\n\n"
-            "If @var{module} has no public interface, @code{#f} is returned.")
-#define FUNC_NAME s_scm_module_public_interface
+SCM
+scm_module_public_interface (SCM module)
 {
-  SCM var;
-
-  SCM_VALIDATE_MODULE (1, module);
-  var = scm_module_local_variable (module, sym_sys_module_public_interface);
-  if (scm_is_true (var))
-    return SCM_VARIABLE_REF (var);
-  else
-    return SCM_BOOL_F;
+  return scm_call_1 (SCM_VARIABLE_REF (module_public_interface_var), module);
 }
-#undef FUNC_NAME
 
 /* scm_sym2var
  *
@@ -899,6 +883,7 @@ scm_post_boot_init_modules ()
   the_root_module_var = scm_c_lookup ("the-root-module");
   default_duplicate_binding_procedures_var = 
     scm_c_lookup ("default-duplicate-binding-procedures");
+  module_public_interface_var = scm_c_lookup ("module-public-interface");
 
   scm_module_system_booted_p = 1;
 }
diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 3dcc8d90f..6110ecf1f 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2218,7 +2218,9 @@ If there is no handler at all, Guile prints an error and then exits."
 ;;; better thought of as a root.
 ;;;
 
-;; module-public-interface is defined in C.
+(define (module-public-interface m)
+  (let ((var (module-local-variable m '%module-public-interface)))
+    (and var (variable-ref var))))
 (define (set-module-public-interface! m i)
   (module-define! m '%module-public-interface i))
 (define (set-system-module! m s)

From 69928c8a3240d8d2417434c18839e098de9f93d8 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 17:22:00 +0200
Subject: [PATCH 14/16] fix some uses of %module-public-interface

* module/ice-9/r5rs.scm:
* module/ice-9/safe-r5rs.scm:
* module/oop/goops/save.scm:
* module/oop/goops/simple.scm:
* module/oop/goops/stklos.scm: Fix some uses of
  %module-public-interface.
---
 module/ice-9/r5rs.scm       | 7 ++++---
 module/ice-9/safe-r5rs.scm  | 5 +++--
 module/oop/goops/save.scm   | 6 ++++--
 module/oop/goops/simple.scm | 5 +++--
 module/oop/goops/stklos.scm | 6 +++---
 5 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/module/ice-9/r5rs.scm b/module/ice-9/r5rs.scm
index c867f9a3c..6432bbc7b 100644
--- a/module/ice-9/r5rs.scm
+++ b/module/ice-9/r5rs.scm
@@ -1,4 +1,4 @@
-;;;; 	Copyright (C) 2000, 2001, 2006 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2000, 2001, 2006, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -31,9 +31,10 @@
 
 	      load))  
 
-(module-use! %module-public-interface (resolve-interface '(ice-9 safe-r5rs)))
+(module-use! (module-public-interface (current-module))
+             (resolve-interface '(ice-9 safe-r5rs)))
 
-(define scheme-report-interface %module-public-interface)
+(define scheme-report-interface (module-public-interface (current-module)))
 
 (define (scheme-report-environment n)
   (if (not (= n 5))
diff --git a/module/ice-9/safe-r5rs.scm b/module/ice-9/safe-r5rs.scm
index f728533cb..a7ab164fa 100644
--- a/module/ice-9/safe-r5rs.scm
+++ b/module/ice-9/safe-r5rs.scm
@@ -1,4 +1,4 @@
-;;;; 	Copyright (C) 2000, 2001, 2004, 2006 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2000, 2001, 2004, 2006, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -129,7 +129,8 @@
 
 (define null-interface (resolve-interface '(ice-9 null)))
 
-(module-use! %module-public-interface null-interface)
+(module-use! (module-public-interface (current-module))
+             null-interface)
 
 (define (null-environment n)
   (if (not (= n 5))
diff --git a/module/oop/goops/save.scm b/module/oop/goops/save.scm
index b51c9e31f..70d8a131c 100644
--- a/module/oop/goops/save.scm
+++ b/module/oop/goops/save.scm
@@ -1,6 +1,6 @@
 ;;; installed-scm-file
 
-;;;; Copyright (C) 2000,2001,2002, 2006, 2009 Free Software Foundation, Inc.
+;;;; Copyright (C) 2000,2001,2002, 2006, 2009, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -848,10 +848,12 @@
     (close-port port)
     objects))
 
+(define iface (module-public-interface (current-module)))
+
 (define-method (load-objects (file <input-port>))
   (let ((m (make-module)))
     (module-use! m the-scm-module)
-    (module-use! m %module-public-interface)
+    (module-use! m iface)
     (save-module-excursion
      (lambda ()
        (set-current-module m)
diff --git a/module/oop/goops/simple.scm b/module/oop/goops/simple.scm
index bc5405a8d..8f4d839c1 100644
--- a/module/oop/goops/simple.scm
+++ b/module/oop/goops/simple.scm
@@ -1,6 +1,6 @@
 ;;; installed-scm-file
 
-;;;; Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+;;;; Copyright (C) 2005, 2006, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -28,4 +28,5 @@
     ((_ arg ...)
      (define-class-with-accessors-keywords arg ...))))
 
-(module-use! %module-public-interface (resolve-interface '(oop goops)))
+(module-use! (module-public-interface (current-module))
+             (resolve-interface '(oop goops)))
diff --git a/module/oop/goops/stklos.scm b/module/oop/goops/stklos.scm
index 718635e4d..8a7ae1636 100644
--- a/module/oop/goops/stklos.scm
+++ b/module/oop/goops/stklos.scm
@@ -34,9 +34,9 @@
 
 ;; Export all bindings that are exported from (oop goops)...
 (module-for-each (lambda (sym var)
-		   (module-add! %module-public-interface sym var))
-		 (nested-ref the-root-module '(%app modules oop goops
-						   %module-public-interface)))
+		   (module-add! (module-public-interface (current-module))
+                                sym var))
+		 (resolve-interface '(oop goops)))
 
 ;; ...but replace the following bindings:
 (export define-class define-method)

From 4e48b4950ecaa10265de6709bf87597a818cf44d Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Fri, 23 Apr 2010 17:16:56 +0200
Subject: [PATCH 15/16] module-public-interface is a field in the module record

* module/ice-9/boot-9.scm (module-public-interface)
  (set-module-public-interface!): Instead of using
  '%module-public-interface, use a field in the module instead.
  (make-module, make-autoload-interface): Adapt.

* module/ice-9/deprecated.scm (module-public-interface):
  (set-module-public-interface!): Add shims so that manually munging
  %module-public-interface should continue to work.
---
 module/ice-9/boot-9.scm     | 13 +++++--------
 module/ice-9/deprecated.scm | 23 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 6110ecf1f..05b6a194a 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -1551,6 +1551,7 @@ If there is no handler at all, Guile prints an error and then exits."
   ;; NOTE: The getter `module-eval-closure' is used in libguile/modules.c.
   ;; NOTE: The getter `module-transfomer' is defined libguile/modules.c.
   ;; NOTE: The getter `module-name' is defined later, due to boot reasons.
+  ;; NOTE: The getter `module-public-interface' is used in libguile/modules.c.
   ;;
   (define-record-type module
     (lambda (obj port) (%print-module obj port))
@@ -1567,7 +1568,8 @@ If there is no handler at all, Guile prints an error and then exits."
      (weak-observers #:no-setter)
      version
      submodules
-     submodule-binder)))
+     submodule-binder
+     public-interface)))
 
 
 ;; make-module &opt size uses binder
@@ -1609,7 +1611,7 @@ If there is no handler at all, Guile prints an error and then exits."
                                           (make-hash-table %default-import-size)
                                           '()
                                           (make-weak-key-hash-table 31) #f
-                                          (make-hash-table 7) #f)))
+                                          (make-hash-table 7) #f #f)))
 
           ;; We can't pass this as an argument to module-constructor,
           ;; because we need it to close over a pointer to the module
@@ -2218,11 +2220,6 @@ If there is no handler at all, Guile prints an error and then exits."
 ;;; better thought of as a root.
 ;;;
 
-(define (module-public-interface m)
-  (let ((var (module-local-variable m '%module-public-interface)))
-    (and var (variable-ref var))))
-(define (set-module-public-interface! m i)
-  (module-define! m '%module-public-interface i))
 (define (set-system-module! m s)
   (set-procedure-property! (module-eval-closure m) 'system-module s))
 (define the-root-module (make-root-module))
@@ -2686,7 +2683,7 @@ If there is no handler at all, Guile prints an error and then exits."
                     (module-local-variable i sym))))))
     (module-constructor (make-hash-table 0) '() b #f #f name 'autoload #f
                         (make-hash-table 0) '() (make-weak-value-hash-table 31) #f
-                        (make-hash-table 0) #f)))
+                        (make-hash-table 0) #f #f)))
 
 (define (module-autoload! module . args)
   "Have @var{module} automatically load the module named @var{name} when one
diff --git a/module/ice-9/deprecated.scm b/module/ice-9/deprecated.scm
index 15e245d1a..d55f20f89 100644
--- a/module/ice-9/deprecated.scm
+++ b/module/ice-9/deprecated.scm
@@ -327,3 +327,26 @@
   (module-define-submodule! the-root-module '%app %app)
   (module-define-submodule! the-root-module 'app %app)
   (module-define-submodule! %app 'modules (resolve-module '() #f)))
+
+;; Allow code that poked %module-public-interface to keep on working.
+;;
+(set! module-public-interface
+      (let ((getter module-public-interface))
+        (lambda (mod)
+          (or (getter mod)
+              (cond
+               ((and=> (module-local-variable mod '%module-public-interface)
+                       variable-ref)
+                => (lambda (iface)
+                     (issue-deprecation-warning 
+"Setting a module's public interface via munging %module-public-interface is
+deprecated. Use set-module-public-interface! instead.")
+                     (set-module-public-interface! mod iface)
+                     iface))
+               (else #f))))))
+
+(set! set-module-public-interface!
+      (let ((setter set-module-public-interface!))
+        (lambda (mod iface)
+          (setter mod iface)
+          (module-define! mod '%module-public-interface iface))))

From 1c1a08238ead8627a65dbc97d6eeb91fe9f8e1a9 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Tue, 27 Apr 2010 22:04:24 +0200
Subject: [PATCH 16/16] comment some global variables in modules.c

* libguile/modules.c: Comment some global variables.
---
 libguile/modules.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libguile/modules.c b/libguile/modules.c
index c8a4c2aa1..ac15eaaac 100644
--- a/libguile/modules.c
+++ b/libguile/modules.c
@@ -42,11 +42,13 @@ int scm_module_system_booted_p = 0;
 
 scm_t_bits scm_module_tag;
 
+/* The current module, a fluid. */
 static SCM the_module;
 
-static SCM module_make_local_var_x_var;
-
+/* Most of the module system is implemented in Scheme. These bindings from
+   boot-9 are needed to provide the Scheme interface. */
 static SCM the_root_module_var;
+static SCM module_make_local_var_x_var;
 static SCM process_define_module_var;
 static SCM process_use_modules_var;
 static SCM resolve_module_var;