From 83619bb6e016c264be996d398a17e2c5f7f5c4ba Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 15 May 1991 18:44:44 +0000
Subject: [PATCH] Implement new procedure os/filename->display-string.  Change
 definition of os/filename-directory, to return false when there's no
 directory component.

---
 v7/src/edwin/unix.scm | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/v7/src/edwin/unix.scm b/v7/src/edwin/unix.scm
index 033eba49e..ce8b3249c 100644
--- a/v7/src/edwin/unix.scm
+++ b/v7/src/edwin/unix.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;	$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/unix.scm,v 1.16 1991/05/14 02:28:17 cph Exp $
+;;;	$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/unix.scm,v 1.17 1991/05/15 18:44:44 cph Exp $
 ;;;
 ;;;	Copyright (c) 1989-91 Massachusetts Institute of Technology
 ;;;
@@ -103,6 +103,17 @@ Includes the new backup.  Must be > 0."
 	(string-append "~/" (pathname->string relative))
 	(pathname->string pathname))))
 
+(define (os/filename->display-string filename)
+  (let ((home (unix/current-home-directory)))
+    (cond ((not (string-prefix? home filename))
+	   filename)
+	  ((string=? home filename)
+	   "~")
+	  ((char=? #\/ (string-ref filename (string-length home)))
+	   (string-append "~" (string-tail filename (string-length home))))
+	  (else
+	   filename))))
+
 (define (os/auto-save-pathname pathname buffer)
   (let ((wrap
 	 (lambda (name directory)
@@ -294,9 +305,8 @@ Includes the new backup.  Must be > 0."
 (define (os/filename-directory filename)
   (let ((end (string-length filename)))
     (let ((index (substring-find-previous-char filename 0 end #\/)))
-      (if index
-	  (substring filename 0 (+ index 1))
-	  "./"))))
+      (and index
+	   (substring filename 0 (+ index 1))))))
 
 (define (os/filename-non-directory filename)
   (let ((end (string-length filename)))
-- 
2.25.1