Add language/wisp, Wisp tests, and SRFI-119 documentation

* doc/ref/srfi-modules.texi (srfi-119): add node
* module/language/wisp.scm: New file.
* module/language/wisp/spec.scm: New file.
* test-suite/tests/srfi-119.test: New file.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

module/language/wisp/spec.scm

@@ -0,0 +1,70 @@
+;;; Language interface for Wisp in Guile
+
+;; Copyright (C) 2005--2014 by David A. Wheeler and Alan Manuel K. Gloria
+;; Copyright (C) 2014--2023 Arne Babenhauserheide.
+;; Copyright (C) 2023 Maxime Devos <maximedevos@telenet.be>
+
+;;;; 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 library; if not, write to the Free Software
+;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+;; adapted from spec.scm: https://gitorious.org/nacre/guile-sweet/?p=nacre:guile-sweet.git;a=blob;f=sweet/spec.scm;hb=ae306867e371cb4b56e00bb60a50d9a0b8353109
+
+(define-module (language wisp spec)
+  #:use-module (language wisp)
+  #:use-module (system base compile)
+  #:use-module (system base language)
+  #:use-module (language scheme compile-tree-il)
+  #:use-module (language scheme decompile-tree-il)
+  #:export (wisp))
+
+;;;
+;;; Language definition
+;;;
+
+
+(define (read-one-wisp-sexp port env)
+  ;; Allow using "# foo" as #(foo).
+  ;; Don't use the globally-acting read-hash-extend, because this
+  ;; doesn't make much sense in parenthese-y (non-Wisp) Scheme.
+  ;; Instead, use fluids to temporarily add the extension.
+  (with-fluids ((%read-hash-procedures (fluid-ref %read-hash-procedures)))
+    (read-hash-extend #\# (lambda args #\# ))
+    ;; Read Wisp files as UTF-8, to support non-ASCII characters.
+    ;; TODO: would be nice to support ';; coding: whatever' lines
+    ;; like in parenthese-y Scheme.
+    (set-port-encoding! port "UTF-8")
+    (if (eof-object? (peek-char port))
+        (read-char port) ; return eof: we’re done
+        (let ((chunk (wisp-scheme-read-chunk port)))
+          (and (not (null? chunk)) ; <---- XXX: maybe (pair? chunk)
+               (car chunk))))))
+
+(define-language wisp
+  #:title "Wisp Scheme Syntax. See SRFI-119 for details"
+  ;; . #:reader read-one-wisp-sexp
+  #:reader read-one-wisp-sexp ; : lambda (port env) : let ((x (read-one-wisp-sexp port env))) (display x)(newline) x ;
+  #:compilers `((tree-il . ,compile-tree-il))
+  #:decompilers `((tree-il . ,decompile-tree-il))
+  #:evaluator (lambda (x module) (primitive-eval x))
+  #:printer write ; TODO: backtransform to Wisp? Use source-properties?
+  #:make-default-environment
+  (lambda ()
+    ;; Ideally we'd duplicate the whole module hierarchy so that `set!',
+    ;; `fluid-set!', etc. don't have any effect in the current environment.
+    (let ((m (make-fresh-user-module)))
+      ;; Provide a separate `current-reader' fluid so that
+      ;; compile-time changes to `current-reader' are
+      ;; limited to the current compilation unit.
+      (module-define! m 'current-reader (make-fluid))
+      m)))