From 0fbe20532529e779d8c0d5280ce6b5322ac869d1 Mon Sep 17 00:00:00 2001
From: Kevin Ryde <user42@zip.com.au>
Date: Mon, 4 Dec 2006 23:38:24 +0000
Subject: [PATCH] (scm_product): For flonum*inum and complex*inum, return exact
 0 if inum==0.  Already done for inum*flonum and inum*complex, and as per R5RS
 section "Exactness".

---
 libguile/numbers.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libguile/numbers.c b/libguile/numbers.c
index c1f11aecb..13e060ec1 100644
--- a/libguile/numbers.c
+++ b/libguile/numbers.c
@@ -3632,6 +3632,9 @@ scm_product (SCM x, SCM y)
     }
   } else if (SCM_REALP (x)) {
     if (SCM_INUMP (y)) {
+      /* inexact*exact0 => exact 0, per R5RS "Exactness" section */
+      if (SCM_EQ_P (y, SCM_INUM0))
+        return y;
       return scm_make_real (SCM_INUM (y) * SCM_REAL_VALUE (x));
     } else if (SCM_BIGP (y)) {
       return scm_make_real (scm_i_big2dbl (y) * SCM_REAL_VALUE (x));
@@ -3645,6 +3648,9 @@ scm_product (SCM x, SCM y)
     }
   } else if (SCM_COMPLEXP (x)) {
     if (SCM_INUMP (y)) {
+      /* inexact*exact0 => exact 0, per R5RS "Exactness" section */
+      if (SCM_EQ_P (y, SCM_INUM0))
+        return y;
       return scm_make_complex (SCM_INUM (y) * SCM_COMPLEX_REAL (x),
 			       SCM_INUM (y) * SCM_COMPLEX_IMAG (x));
     } else if (SCM_BIGP (y)) {