From: Chris Hanson <org/chris-hanson/cph>
Date: Sun, 29 Jan 2017 04:26:35 +0000 (-0800)
Subject: Simplify logic for printing generic I/O ports.
X-Git-Tag: mit-scheme-pucked-9.2.12~227^2~36
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=ad3f8af85cea7cff823c6411e1189a3aaeef93c7;p=mit-scheme.git

Simplify logic for printing generic I/O ports.
---

diff --git a/src/runtime/genio.scm b/src/runtime/genio.scm
index ed2cd6f95..8669b9b59 100644
--- a/src/runtime/genio.scm
+++ b/src/runtime/genio.scm
@@ -339,17 +339,18 @@ USA.
 	 (output-buffer-open? ob))))
 
 (define (generic-io/write-self port output-port)
-  (cond ((i/o-port? port)
-	 (write-string " for channels: " output-port)
-	 (write (generic-io/input-channel port) output-port)
-	 (write-string " " output-port)
-	 (write (generic-io/output-channel port) output-port))
-	((input-port? port)
-	 (write-string " for channel: " output-port)
-	 (write (generic-io/input-channel port) output-port))
-	((output-port? port)
-	 (write-string " for channel: " output-port)
-	 (write (generic-io/output-channel port) output-port))))
+  (let ((ib (port-input-buffer port))
+	(ob (port-output-buffer port)))
+    (let ((ic (and ib (input-buffer-channel ib)))
+	  (oc (and ob (output-buffer-channel ob))))
+      (cond ((and ic oc (not (eq? ic oc)))
+	     (write-string " for channels: " output-port)
+	     (write ic output-port)
+	     (write-string " " output-port)
+	     (write oc output-port))
+	    ((or ic oc)
+	     (write-string " for channel: " output-port)
+	     (write (or ic oc) output-port))))))
 
 (define (generic-io/supports-coding? port)
   port