From dfe3a75b3f64ac993f64c6380c442de53ec21235 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 22 Feb 2017 01:25:22 -0800
Subject: [PATCH] Add unicode support to string-replace.

---
 src/runtime/runtime.pkg |  3 +--
 src/runtime/string.scm  | 26 --------------------------
 src/runtime/ustring.scm |  7 +++++++
 3 files changed, 8 insertions(+), 28 deletions(-)

diff --git a/src/runtime/runtime.pkg b/src/runtime/runtime.pkg
index cfecd6195..becea1c84 100644
--- a/src/runtime/runtime.pkg
+++ b/src/runtime/runtime.pkg
@@ -1046,7 +1046,6 @@ USA.
 	  string-match-forward-ci
 	  string-pad-left
 	  string-pad-right
-	  string-replace
 	  string-search-all
 	  string-search-backward
 	  string-search-forward
@@ -1057,7 +1056,6 @@ USA.
 	  substring-match-backward-ci
 	  substring-match-forward
 	  substring-match-forward-ci
-	  substring-replace
 	  substring-search-all
 	  substring-search-backward
 	  substring-search-forward
@@ -1140,6 +1138,7 @@ USA.
 	  string-prefix-ci?
 	  string-prefix?
 	  string-ref
+	  string-replace
 	  string-set!
 	  string-slice
 	  string-splitter
diff --git a/src/runtime/string.scm b/src/runtime/string.scm
index 6768eb580..80f230186 100644
--- a/src/runtime/string.scm
+++ b/src/runtime/string.scm
@@ -89,32 +89,6 @@ USA.
 	(string-set! result j (string-ref string i)))
       result)))
 
-;;;; Replace
-
-(define (string-replace string char1 char2)
-  (guarantee-string string 'STRING-REPLACE)
-  (guarantee-char char1 'STRING-REPLACE)
-  (guarantee-char char2 'STRING-REPLACE)
-  (let ((string (string-copy string)))
-    (%substring-replace! string 0 (string-length string) char1 char2)
-    string))
-
-(define (substring-replace string start end char1 char2)
-  (guarantee-substring string start end 'SUBSTRING-REPLACE)
-  (guarantee-char char1 'SUBSTRING-REPLACE)
-  (guarantee-char char2 'SUBSTRING-REPLACE)
-  (let ((string (string-copy string)))
-    (%substring-replace! string start end char1 char2)
-    string))
-
-(define (%substring-replace! string start end char1 char2)
-  (let loop ((start start))
-    (let ((index (substring-find-next-char string start end char1)))
-      (if index
-	  (begin
-	    (string-set! string index char2)
-	    (loop (fix:+ index 1)))))))
-
 ;;;; Compare
 
 (define (string-compare string1 string2 if= if< if>)
diff --git a/src/runtime/ustring.scm b/src/runtime/ustring.scm
index 664454bfa..c3663c4f9 100644
--- a/src/runtime/ustring.scm
+++ b/src/runtime/ustring.scm
@@ -780,6 +780,13 @@ USA.
 
 (define (burst-string string delimiter allow-runs?)
   ((string-splitter delimiter allow-runs?) string))
+
+(define (string-replace string char1 char2)
+  (guarantee bitless-char? char1 'string-replace)
+  (guarantee bitless-char? char2 'string-replace)
+  (string-map (lambda (char)
+		(if (char=? char char1) char2 char))
+	      string))
 
 (define (string-8-bit? string)
   (receive (string start end) (translate-slice string 0 (string-length string))
-- 
2.25.1