From: Taylor R Campbell <campbell@mumble.net>
Date: Sun, 18 Nov 2018 04:09:23 +0000 (+0000)
Subject: Fix printing signed zero imaginary part.
X-Git-Tag: mit-scheme-pucked-10.1.2~16^2~31
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=313b951ff0eed638bd3350c3790a8ec65a16c218;p=mit-scheme.git

Fix printing signed zero imaginary part.
---

diff --git a/src/runtime/arith.scm b/src/runtime/arith.scm
index e5409c8cd..ffbf8cb08 100644
--- a/src/runtime/arith.scm
+++ b/src/runtime/arith.scm
@@ -1977,6 +1977,11 @@ USA.
 		(real:->string i radix))
 	       ((real:negative? i)
 		(string-append "-" (positive-case (real:negate i))))
+	       ((and (flo:flonum? i)
+		     (flo:zero? i)
+		     (flo:negative? (flo:copysign 1. i)))
+		;; Not negative, but positive case gives `+-0.'.
+		"-0.")
 	       (else
 		(string-append "+" (positive-case i)))))
        (if imaginary-unit-j? "j" "i"))
diff --git a/tests/runtime/test-readwrite.scm b/tests/runtime/test-readwrite.scm
index 86575759a..792f74a62 100644
--- a/tests/runtime/test-readwrite.scm
+++ b/tests/runtime/test-readwrite.scm
@@ -93,9 +93,9 @@ USA.
     ("123" ,assert-exact-integer)
     ("1/34" ,assert-exact-rational)
     ("123+456i" ,assert-complex-nonreal)
-    ("-0.i" ,assert-real xfail)         ;real?
-    ("0.-0.i" ,assert-real xfail)       ;real?
-    ("-0.-0.i" ,assert-real xfail)      ;real?
+    ("-0.i" ,assert-real)               ;real?
+    ("0.-0.i" ,assert-real)             ;real?
+    ("-0.-0.i" ,assert-real)            ;real?
     ("1.23" ,assert-flonum)
     ("+inf.0i" ,assert-complex-nonreal)
     ("-inf.0i" ,assert-complex-nonreal)