diff --git a/compiler/kernel-primitives.rkt b/compiler/kernel-primitives.rkt
index 01a6e75..ecd1216 100644
--- a/compiler/kernel-primitives.rkt
+++ b/compiler/kernel-primitives.rkt
@@ -108,6 +108,8 @@
                                     'hash-remove!
                                     'hash-remove
                                     'equal-hash-code
+
+                                    'string-copy
                                     ))
 (define-predicate KernelPrimitiveName? KernelPrimitiveName)
 
diff --git a/js-assembler/runtime-src/baselib-primitives.js b/js-assembler/runtime-src/baselib-primitives.js
index 867fdfd..4c51476 100644
--- a/js-assembler/runtime-src/baselib-primitives.js
+++ b/js-assembler/runtime-src/baselib-primitives.js
@@ -791,7 +791,15 @@
             if (M.a === 3) {
                 end = baselib.numbers.toFixnum(checkNatural(M, 'substring', 2));
             }
-            return str.substring(start, end);
+            return baselib.strings.makeMutableString((str.substring(start, end)).split(""));
+        });
+
+    installPrimitiveProcedure(
+        'string-copy',
+        1,
+        function(M) {
+            var str = checkString(M, 'substring', 0).toString();
+            return baselib.strings.makeMutableString(str.substring(0, str.length).split(""));
         });
 
 
diff --git a/js-assembler/runtime-src/baselib-strings.js b/js-assembler/runtime-src/baselib-strings.js
index a22dbc5..13bc786 100644
--- a/js-assembler/runtime-src/baselib-strings.js
+++ b/js-assembler/runtime-src/baselib-strings.js
@@ -96,7 +96,7 @@
     };
 
     Str.prototype.replace = function (expr, newStr) {
-	return Str.fromString( this.toString().replace(expr, newStr) );
+	return Str.fromString(this.toString().replace(expr, newStr) );
     };
 
 
@@ -117,11 +117,11 @@
     };
 
     Str.prototype.toUpperCase = function () {
-	return Str.fromString( this.chars.join("").toUpperCase() );
+	return Str.fromString(this.chars.join("").toUpperCase() );
     };
 
     Str.prototype.toLowerCase = function () {
-	return Str.fromString( this.chars.join("").toLowerCase() );
+	return Str.fromString(this.chars.join("").toLowerCase() );
     };
 
     Str.prototype.match = function (regexpr) {
diff --git a/lang/kernel.rkt b/lang/kernel.rkt
index 337735b..334ecff 100644
--- a/lang/kernel.rkt
+++ b/lang/kernel.rkt
@@ -431,6 +431,7 @@ box?
   string-ci<=?
   string-ci>=?
 
+  string-copy
   substring
   string-append
   string->list
diff --git a/tests/more-tests/dots-should-be-syntax-error.rkt b/tests/more-tests/dots-should-be-syntax-error.rkt
new file mode 100644
index 0000000..990de08
--- /dev/null
+++ b/tests/more-tests/dots-should-be-syntax-error.rkt
@@ -0,0 +1,3 @@
+#lang planet dyoo/whalesong/cs019
+
+.. ;; should raise a teaching syntax error
diff --git a/tests/more-tests/string-tests.expected b/tests/more-tests/string-tests.expected
index e6790f6..87d3b19 100644
--- a/tests/more-tests/string-tests.expected
+++ b/tests/more-tests/string-tests.expected
@@ -11,6 +11,7 @@
 ""
 "l"
 "lo"
+"hello world"
 ""
 "hello"
 ""
diff --git a/tests/more-tests/string-tests.rkt b/tests/more-tests/string-tests.rkt
index 12a643d..e033727 100644
--- a/tests/more-tests/string-tests.rkt
+++ b/tests/more-tests/string-tests.rkt
@@ -14,6 +14,8 @@
 (substring "hello world" 3 4)
 (substring "hello world" 3 5)
 
+(string-copy "hello world")
+
 
 (list->string '())
 (list->string '(#\h #\e #\l #\l #\o))
diff --git a/version.rkt b/version.rkt
index 15e32b5..11184ff 100644
--- a/version.rkt
+++ b/version.rkt
@@ -6,4 +6,4 @@
 
 (provide version)
 (: version String)
-(define version "1.62")
+(define version "1.64")