* reimplementation of values, call-with-values as primitives:

	* values.c, values.h: new files.  use a struct to contain multiple
	values, similar to the previous Scheme-level implementation.
	* Makefile.am: add values.c, values.h, values.x.
	* continuations.c (continuation_apply): support R5RS multiple value
	continuations.
	* init.c: call scm_init_values.
	* struct.h: define SCM_SET_STRUCT_PRINTER.

1 files changed, 154 insertions, 0 deletions

diff --git a/libguile/values.c b/libguile/values.c
new file mode 100644
index 000000000..6575a147c
--- /dev/null
+++ b/libguile/values.c
@@ -0,0 +1,154 @@
+/* Copyright (C) 2000 Free Software Foundation, Inc.
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ * 
+ * This program 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307 USA
+ *
+ * As a special exception, the Free Software Foundation gives permission
+ * for additional uses of the text contained in its release of GUILE.
+ *
+ * The exception is that, if you link the GUILE library with other files
+ * to produce an executable, this does not by itself cause the
+ * resulting executable to be covered by the GNU General Public License.
+ * Your use of that executable is in no way restricted on account of
+ * linking the GUILE library code into it.
+ *
+ * This exception does not however invalidate any other reasons why
+ * the executable file might be covered by the GNU General Public License.
+ *
+ * This exception applies only to the code released by the
+ * Free Software Foundation under the name GUILE.  If you copy
+ * code from other Free Software Foundation releases into a copy of
+ * GUILE, as the General Public License permits, the exception does
+ * not apply to the code that you add in this way.  To avoid misleading
+ * anyone as to the status of such modified files, you must delete
+ * this exception notice from them.
+ *
+ * If you write modifications of your own for GUILE, it is your choice
+ * whether to permit this exception to apply to your modifications.
+ * If you do not wish that, delete this exception notice.  */
+
+#include "libguile/_scm.h"
+#include "libguile/eval.h"
+#include "libguile/feature.h"
+#include "libguile/gc.h"
+#include "libguile/numbers.h"
+#include "libguile/ports.h"
+#include "libguile/root.h"
+#include "libguile/strings.h"
+#include "libguile/struct.h"
+#include "libguile/validate.h"
+
+#include "libguile/values.h"
+
+static SCM values_vtable;
+
+#define SCM_VALUESP(x) (SCM_STRUCTP (x)\
+                        && SCM_EQ_P (scm_struct_vtable (x), values_vtable))
+
+static SCM
+print_values (SCM obj, SCM pwps)
+{
+  SCM values = scm_struct_ref (obj, SCM_INUM0);
+  SCM port = SCM_PORT_WITH_PS_PORT (pwps);
+  scm_print_state *ps = SCM_PRINT_STATE (SCM_PORT_WITH_PS_PS (pwps));
+
+  while (SCM_CONSP (values))
+    {
+      scm_iprin1 (SCM_CAR (values), port, ps);
+      values = SCM_CDR (values);
+      if (SCM_CONSP (values))
+	scm_newline (port);
+    }
+  return SCM_UNSPECIFIED;
+}
+
+SCM_DEFINE (scm_values, "values", 0, 0, 1,
+	    (SCM args),
+	    "Delivers all of its arguments to its continuation.  Except for\n"
+	    "continuations created by the `call-with-values' procedure, all\n"
+	    "continuations take exactly one value.  The effect of passing no\n"
+	    "value or more than one value to continuations that were not\n"
+	    "created by call-with-values is unspecified.")
+#define FUNC_NAME s_scm_values
+{
+  long n;
+  SCM result;
+
+  SCM_VALIDATE_LIST_COPYLEN (1, args, n);
+  if (n == 1)
+    result = SCM_CAR (args);
+  else
+    {
+      result = scm_make_struct (values_vtable, SCM_INUM0,
+				scm_cons (args, SCM_EOL));
+    }
+
+  return result;
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_call_with_values, "call-with-values", 2, 0, 0,
+	    (SCM producer, SCM consumer),
+	    "Calls its @var{producer} argument with no values and a\n"
+	    "continuation that, when passed some values, calls the\n"
+	    "@var{consumer} procedure with those values as arguments.  The\n"
+	    "continuation for the call to @var{consumer} is the continuation\n"
+	    "of the call to call-with-values.\n\n"
+	    "@example\n"
+	    "(call-with-values (lambda () (values 4 5))\n"
+	    "                  (lambda (a b) b))\n"
+	    "                                             ==>  5\n\n"
+	    "@end example\n"
+	    "@example\n"
+	    "(call-with-values * -)                             ==>  -1\n"
+	    "@end example")
+#define FUNC_NAME s_scm_call_with_values
+{
+  SCM product;
+
+  SCM_VALIDATE_PROC (1, producer);
+  SCM_VALIDATE_PROC (2, consumer);
+
+  product = scm_apply (producer, SCM_EOL, SCM_EOL);
+  if (SCM_VALUESP (product))
+    product = scm_struct_ref (product, SCM_INUM0);
+  else
+    product = scm_cons (product, SCM_EOL);
+  return scm_apply (consumer, product, SCM_EOL);
+}
+#undef FUNC_NAME
+
+void
+scm_init_values (void)
+{
+  SCM print = scm_make_subr ("%print-values", scm_tc7_subr_2, print_values);
+
+  values_vtable 
+    = scm_permanent_object (scm_make_vtable_vtable (scm_makfrom0str ("pr"),
+						    SCM_INUM0, SCM_EOL));
+  SCM_SET_STRUCT_PRINTER (values_vtable, print);
+
+  scm_add_feature ("values");
+
+#ifndef SCM_MAGIC_SNARFER
+#include "libguile/values.x"
+#endif
+}
+
+/*
+  Local Variables:
+  c-file-style: "gnu"
+  End:
+*/