Replace "pr" struct fields with "pw" fields

* libguile/struct.h (SCM_VTABLE_BASE_LAYOUT): Layout is a "pr" field.
* module/ice-9/boot-9.scm (record-type-vtable): Record vtable fields are
  writable.
  (<parameter>): "pw" fields.
* module/oop/goops.scm (<class>, %compute-layout): <read-only> fields
  are "pw" underneath.
* module/rnrs/records/procedural.scm (record-type-vtable)
  (record-constructor-vtable, make-record-type-descriptor): Use "pw"
  fields in vtables.
* module/srfi/srfi-35.scm (%condition-type-vtable)
  (struct-layout-for-condition): "pw" fields in vtables.
* test-suite/tests/goops.test:
* test-suite/tests/structs.test: Use "pw" fields only.
* benchmark-suite/benchmarks/structs.bm: Update for make-struct/no-tail,
  to use pw fields, and also to remove useless tests that the compiler
  would optimize away.
* doc/ref/api-data.texi (Vtables): Add a note about the now-vestigial
  permissions character and update documentation.
  (Structure Basics, Meta-Vtables): Update examples.
* libguile/hash.c (scm_i_struct_hash): Remove code that would handle
  opaque/self fields.
* libguile/print.h (SCM_PRINT_STATE_LAYOUT): Use "pw" fields.
* libguile/struct.c (scm_struct_init): Simplify check for hidden
  fields.
* libguile/values.c (scm_init_values): Field is "pw".

2 files changed, 14 insertions, 20 deletions

diff --git a/test-suite/tests/goops.test b/test-suite/tests/goops.test
index 390cd8c74..4536a468d 100644
--- a/test-suite/tests/goops.test
+++ b/test-suite/tests/goops.test
@@ -1,6 +1,6 @@
 ;;;; goops.test --- test suite for GOOPS                      -*- scheme -*-
 ;;;;
-;;;; Copyright (C) 2001,2003,2004, 2006, 2008, 2009, 2011, 2012, 2014, 2015 Free Software Foundation, Inc.
+;;;; Copyright (C) 2001,2003,2004, 2006, 2008, 2009, 2011, 2012, 2014, 2015, 2017 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
@@ -148,7 +148,7 @@
     ;; Previously, `class-of' would fail for nameless structs, i.e., structs
     ;; for which `struct-vtable-name' is #f.
     (is-a? (class-of (make-vtable
-                      (string-append standard-vtable-fields "prprpr")))
+                      (string-append standard-vtable-fields "pwpwpw")))
            <class>))
 
   ;; Two cases: one for structs created before goops, one after.
@@ -157,7 +157,7 @@
          (class-of (current-module))))
   (pass-if "late vtable class cached"
     (let ((vtable (make-vtable
-                   (string-append standard-vtable-fields "prprpr"))))
+                   (string-append standard-vtable-fields "pwpwpw"))))
       (eq? (class-of vtable)
            (class-of vtable)))))
 
diff --git a/test-suite/tests/structs.test b/test-suite/tests/structs.test
index c18e42194..3cbc67db3 100644
--- a/test-suite/tests/structs.test
+++ b/test-suite/tests/structs.test
@@ -27,7 +27,7 @@
 ;;;
 
 (define ball-root
-  (make-vtable (string-append standard-vtable-fields "pr") 0))
+  (make-vtable (string-append standard-vtable-fields "pw") 0))
 
 (define (make-ball-type ball-color)
   (make-struct/no-tail ball-root
@@ -69,13 +69,7 @@
 	  ;; end of the vtable tower
 	  (eq? (struct-vtable <standard-vtable>) <standard-vtable>)))
 
-  (pass-if-exception "write-access denied"
-     exception:struct-set!-denied
-
-     ;; The first field of instances of BALL-ROOT is read-only.
-     (struct-set! red vtable-offset-user "blue"))
-
-  (pass-if "write-access granted"
+  (pass-if "write"
      (set-owner! (make-ball red "Bob") "Fred")
      #t)
 
@@ -98,7 +92,7 @@
 
   (pass-if-exception "struct-ref out-of-range"
      exception:out-of-range
-     (let* ((v (make-vtable "prpr"))
+     (let* ((v (make-vtable "pwpw"))
             (s (make-struct/no-tail v 'a 'b)))
        (struct-ref s 2)))
 
@@ -112,7 +106,7 @@
 (with-test-prefix "equal?"
 
   (pass-if "simple structs"
-     (let* ((vtable (make-vtable "pr"))
+     (let* ((vtable (make-vtable "pw"))
             (s1     (make-struct/no-tail vtable "hello"))
             (s2     (make-struct/no-tail vtable "hello")))
        (equal? s1 s2)))
@@ -130,21 +124,21 @@
 (with-test-prefix "hash"
 
   (pass-if "simple structs"
-    (let* ((v  (make-vtable "pr"))
+    (let* ((v  (make-vtable "pw"))
            (s1 (make-struct/no-tail v "hello"))
            (s2 (make-struct/no-tail v "hello")))
       (= (hash s1 7777) (hash s2 7777))))
 
   (pass-if "different structs"
-    (let* ((v  (make-vtable "pr"))
+    (let* ((v  (make-vtable "pw"))
            (s1 (make-struct/no-tail v "hello"))
            (s2 (make-struct/no-tail v "world")))
       (or (not (= (hash s1 7777) (hash s2 7777)))
           (throw 'unresolved))))
 
   (pass-if "different struct types"
-    (let* ((v1 (make-vtable "pr"))
-           (v2 (make-vtable "pr"))
+    (let* ((v1 (make-vtable "pw"))
+           (v2 (make-vtable "pw"))
            (s1 (make-struct/no-tail v1 "hello"))
            (s2 (make-struct/no-tail v2 "hello")))
       (or (not (= (hash s1 7777) (hash s2 7777)))
@@ -156,7 +150,7 @@
       (= (hash s1 7777) (hash s2 7777))))
 
   (pass-if "struct with weird fields"
-    (let* ((v  (make-vtable "prurph"))
+    (let* ((v  (make-vtable "pwuwph"))
            (s1 (make-struct/no-tail v "hello" 123 "invisible-secret1"))
            (s2 (make-struct/no-tail v "hello" 123 "invisible-secret2")))
       (= (hash s1 7777) (hash s2 7777))))
@@ -191,7 +185,7 @@
 (with-test-prefix "make-vtable"
 
   (pass-if "without printer"
-    (let* ((vtable (make-vtable "pwpr"))
+    (let* ((vtable (make-vtable "pwpw"))
 	   (struct (make-struct/no-tail vtable 'x 'y)))
       (and (eq? 'x (struct-ref struct 0))
 	   (eq? 'y (struct-ref struct 1)))))
@@ -201,7 +195,7 @@
       (define (print struct port)
 	(display "hello" port))
 	
-      (let* ((vtable (make-vtable "pwpr" print))
+      (let* ((vtable (make-vtable "pwpw" print))
 	     (struct (make-struct/no-tail vtable 'x 'y))
 	     (str    (call-with-output-string
 		      (lambda (port)