From 1729d8ff31a255eba2cc845d6875dcbdbb963156 Mon Sep 17 00:00:00 2001
From: Mikael Djurfeldt <djurfeldt@nada.kth.se>
Date: Tue, 10 Nov 1998 14:40:28 +0000
Subject: [PATCH] * boot-9.scm (values, call-with-values): Moved here from
 syncase.scm.

---
 ice-9/boot-9.scm | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
index ef63d6ded..31909fe3d 100644
--- a/ice-9/boot-9.scm
+++ b/ice-9/boot-9.scm
@@ -493,6 +493,31 @@
 	(loop (cons init answer) (- n 1)))))
 
 
+
+;;; {Multiple return values}
+
+(define *values-rtd*
+  (make-record-type "values"
+		    '(values)))
+
+(define values
+  (let ((make-values (record-constructor *values-rtd*)))
+    (lambda x
+      (if (and (not (null? x))
+	       (null? (cdr x)))
+	  (car x)
+	  (make-values x)))))
+
+(define call-with-values
+  (let ((access-values (record-accessor *values-rtd* 'values))
+	(values-predicate? (record-predicate *values-rtd*)))
+    (lambda (producer consumer)
+      (let ((result (producer)))
+	(if (values-predicate? result)
+	    (apply consumer (access-values result))
+	    (consumer result))))))
+
+
 
 ;;; {and-map, or-map, and map-in-order}
 ;;;