[PATCH v9 06/18] Share features tested by cond-expand library declarations and expressions.

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

This addresses a FIXME in r7rs-libraries.scm, which was about the
cond-expand define-library declarations not using the same features as
provided in (scheme base).

* .gitignore: Register /module/ice-9/endianness.scm.
* am/bootstrap.am (NOCOMP_SOURCES): Register ice-9/endianness.scm and
scheme/features.scm.
* configure.ac: Define a NATIVE_ENDIANNESS output variable.
* module/ice-9/endianness.scm.in: New file.
* module/scheme/base.scm (features): Move to...
* module/scheme/features.scm: ... here.  Include this file in base.scm
and...
* module/ice-9/r7rs-libraries.scm: ... here.
(define-library) <handle-cond-expand>: Adjust to match the definition of
cond-expand found in (scheme base).
* module/ice-9/boot-9.scm (%cond-expand-features): Move before where
r7rs-libraries.scm is included.
* NEWS: Update NEWS.

---

(no changes since v5)

Changes in v5:
 - Update NEWS

 .gitignore                      |  1 +
 NEWS                            |  1 +
 am/bootstrap.am                 |  2 ++
 configure.ac                    |  7 +++-
 module/ice-9/boot-9.scm         | 62 +++++++++++++++++----------------
 module/ice-9/endianness.scm.in  |  1 +
 module/ice-9/r7rs-libraries.scm |  6 ++--
 module/scheme/base.scm          | 10 ++----
 module/scheme/features.scm      | 44 +++++++++++++++++++++++
 9 files changed, 92 insertions(+), 42 deletions(-)
 create mode 100644 module/ice-9/endianness.scm.in
 create mode 100644 module/scheme/features.scm

diff --git a/.gitignore b/.gitignore
index 931ebf7c4..7903bee15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -122,6 +122,7 @@ INSTALL
 /meta/guild
 /meta/guile-config
 /lib/locale.h
+/module/ice-9/endianness.scm
 /module/ice-9/eval.go.stamp
 /doc/ref/standard-library.texi
 /doc/ref/standard-libraryscmfiles
diff --git a/NEWS b/NEWS
index 1de1fa8b4..e5cc3c7aa 100644
--- a/NEWS
+++ b/NEWS
@@ -56,6 +56,7 @@ other operations, given the internal use of those functions.
 ** R7RS define-library now properly supports 'rename' declarations
    (<https://bugs.gnu.org/67255>)
 ** (scheme base)'s cond-expand supports non-negative integer in modules names
+** define-library's cond-expand declarations can now test complete features
 
 \f
 Changes in 3.0.9 (since 3.0.8)
diff --git a/am/bootstrap.am b/am/bootstrap.am
index a71946958..39f65f100 100644
--- a/am/bootstrap.am
+++ b/am/bootstrap.am
@@ -427,12 +427,14 @@ ELISP_SOURCES =					\
   language/elisp/boot.el
 
 NOCOMP_SOURCES =				\
+  ice-9/endianness.scm				\
   ice-9/match.upstream.scm			\
   ice-9/psyntax.scm				\
   ice-9/read.scm				\
   ice-9/r6rs-libraries.scm			\
   ice-9/r7rs-libraries.scm			\
   ice-9/quasisyntax.scm				\
+  scheme/features.scm				\
   srfi/srfi-42/ec.scm				\
   srfi/srfi-64/testing.scm			\
   srfi/srfi-67/compare.scm			\
diff --git a/configure.ac b/configure.ac
index d0a2dc79b..d049a5a1b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -326,7 +326,12 @@ else
 fi
 AC_CHECK_LIB(uca, __uc_get_ar_bsp)
 
-AC_C_BIGENDIAN
+AC_C_BIGENDIAN(
+  [AC_DEFINE([WORDS_BIGENDIAN], 1)
+   AC_SUBST([NATIVE_ENDIANNESS], [big])],
+  [AC_SUBST([NATIVE_ENDIANNESS], [little])]
+)
+AC_CONFIG_FILES([module/ice-9/endianness.scm])
 
 AC_C_LABELS_AS_VALUES
 
diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index a79d49ae1..3da328b2a 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -4066,6 +4066,38 @@ but it fails to load."
              (process-use-modules (list quoted-args ...))
              *unspecified*))))))
 
+;;; This is defined early because ice-9/r7rs-libraries makes use of
+;;; the R7RS features, which requires it to be defined.
+(define %cond-expand-features
+  ;; This should contain only features that are present in core Guile,
+  ;; before loading any modules.  Modular features are handled by
+  ;; placing 'cond-expand-provide' in the relevant module.
+  '(guile
+    guile-2
+    guile-2.2
+    guile-3
+    guile-3.0
+    r5rs
+    r6rs
+    r7rs
+    exact-closed ieee-float full-unicode ratios ;; R7RS features.
+    srfi-0   ;; cond-expand itself
+    srfi-4   ;; homogeneous numeric vectors
+    srfi-6   ;; string ports
+    srfi-13  ;; string library
+    srfi-14  ;; character sets
+    srfi-16  ;; case-lambda
+    srfi-23  ;; `error` procedure
+    srfi-30  ;; nested multi-line comments
+    srfi-39  ;; parameterize
+    srfi-46  ;; basic syntax-rules extensions
+    srfi-55  ;; require-extension
+    srfi-61  ;; general cond clause
+    srfi-62  ;; s-expression comments
+    srfi-87  ;; => in case clauses
+    srfi-105 ;; curly infix expressions
+    ))
+
 (include-from-path "ice-9/r6rs-libraries")
 (include-from-path "ice-9/r7rs-libraries")
 
@@ -4535,36 +4567,6 @@ when none is available, reading FILE-NAME with READER."
 ;;; Remember to update the features list when adding more SRFIs.
 ;;;
 
-(define %cond-expand-features
-  ;; This should contain only features that are present in core Guile,
-  ;; before loading any modules.  Modular features are handled by
-  ;; placing 'cond-expand-provide' in the relevant module.
-  '(guile
-    guile-2
-    guile-2.2
-    guile-3
-    guile-3.0
-    r5rs
-    r6rs
-    r7rs
-    exact-closed ieee-float full-unicode ratios ;; R7RS features.
-    srfi-0   ;; cond-expand itself
-    srfi-4   ;; homogeneous numeric vectors
-    srfi-6   ;; string ports
-    srfi-13  ;; string library
-    srfi-14  ;; character sets
-    srfi-16  ;; case-lambda
-    srfi-23  ;; `error` procedure
-    srfi-30  ;; nested multi-line comments
-    srfi-39  ;; parameterize
-    srfi-46  ;; basic syntax-rules extensions
-    srfi-55  ;; require-extension
-    srfi-61  ;; general cond clause
-    srfi-62  ;; s-expression comments
-    srfi-87  ;; => in case clauses
-    srfi-105 ;; curly infix expressions
-    ))
-
 ;; This table maps module public interfaces to the list of features.
 ;;
 (define %cond-expand-table (make-hash-table))
diff --git a/module/ice-9/endianness.scm.in b/module/ice-9/endianness.scm.in
new file mode 100644
index 000000000..5d3f5dbaa
--- /dev/null
+++ b/module/ice-9/endianness.scm.in
@@ -0,0 +1 @@
+(define %native-endianness '@NATIVE_ENDIANNESS@)
diff --git a/module/ice-9/r7rs-libraries.scm b/module/ice-9/r7rs-libraries.scm
index 773a9d47b..20692989d 100644
--- a/module/ice-9/r7rs-libraries.scm
+++ b/module/ice-9/r7rs-libraries.scm
@@ -29,6 +29,8 @@
 (define-syntax-rule (include-ci filename)
   (include filename))
 
+(include-from-path "scheme/features.scm")
+
 (define-syntax define-library
   (lambda (stx)
     (define (r7rs-module-name->r6rs-module-name name)
@@ -91,9 +93,7 @@
               (syntax->datum #'lib-name)))))
           (id
            (identifier? #'id)
-           ;; FIXME: R7RS (features) isn't quite the same as
-           ;; %cond-expand-features; see scheme/base.scm.
-           (memq (syntax->datum #'id) %cond-expand-features))))
+           (memq (syntax->datum #'id) (features)))))
       (syntax-case clauses (else)
         (() #'())  ; R7RS says this is not specified :-/
         (((else decl ...))
diff --git a/module/scheme/base.scm b/module/scheme/base.scm
index 2bd1f0d89..1f47f8560 100644
--- a/module/scheme/base.scm
+++ b/module/scheme/base.scm
@@ -272,6 +272,8 @@
          (make-exception exn
                          (make-exception-with-irritants irritants))))))
 
+(include-from-path "scheme/features.scm")
+
 (define-syntax r7:cond-expand
   (lambda (x)
     (define (has-req? req)
@@ -551,14 +553,6 @@
       (exact->inexact (expt x y))
       (expt x y)))
 
-(define (features)
-  (append
-   (case (native-endianness)
-     ((big) '(big-endian))
-     ((little) '(little-endian))
-     (else '()))
-   %cond-expand-features))
-
 (define (input-port-open? port)
   (and (not (port-closed? port)) (input-port? port)))
 
diff --git a/module/scheme/features.scm b/module/scheme/features.scm
new file mode 100644
index 000000000..7acbe332b
--- /dev/null
+++ b/module/scheme/features.scm
@@ -0,0 +1,44 @@
+;;; R7RS compatibility libraries -- features
+;;; Copyright (C) 2019-2023 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 License as
+;;; published by the Free Software Foundation, either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; This library is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this program.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Based on code from https://gitlab.com/akku/akku-scm, written
+;;; 2018-2019 by Göran Weinholt <goran@weinholt.se>, as well as
+;;; https://github.com/okuoku/yuni, written 2014-2018 by OKUMURA Yuki
+;;; <mjt@cltn.org>.  This code was originally released under the
+;;; following terms:
+;;;
+;;;     To the extent possible under law, the author(s) have dedicated
+;;;     all copyright and related and neighboring rights to this
+;;;     software to the public domain worldwide. This software is
+;;;     distributed without any warranty.
+;;;
+;;;     See <http://creativecommons.org/publicdomain/zero/1.0/>, for a
+;;;     copy of the CC0 Public Domain Dedication.
+
+;;; This code is shared between (scheme base) and (ice-9
+;;; r7rs-libraries), which gets included in (ice-9 boot-9), to avoid
+;;; having multiple copies 'features' to maintain.
+
+(include-from-path "ice-9/endianness.scm")
+
+(define (features)
+  (append
+   (case %native-endianness
+     ((big) '(big-endian))
+     ((little) '(little-endian))
+     (else '()))
+   %cond-expand-features))
-- 
2.41.0