distinguish strings created from symbol->string

google · Nov 20, 2019 · 2180857 · 2180857
1 parent 7e5adbe
commit 2180857
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Showing 2 changed files with 7 additions and 4 deletions.
diff --git a/rt/rt.mjs b/rt/rt.mjs
@@ -126,7 +126,8 @@ function rt(engine) {
         // that's not specified on the Scheme language level.  Using JS
         // strings for symbols allows us to compare with ===, as is
         // required.
-        'string?': x => x instanceof String && x.charAt(0) === 's',
+        'string?': x => (typeof x === 'string' || x instanceof String)
+                     && x.charAt(0) === 's',
         '%symbol?': x => typeof(x) === 'string' && x.charAt(0) === 'S',
         '%string=?' : (x, y) => x.valueOf() === y.valueOf(),
 
@@ -145,7 +146,7 @@ function rt(engine) {
         },
 
         '%string->symbol': value => 'S' + value,
-        '%symbol->string': x => new String (x.substring(1)),
+        '%symbol->string': x => x.substring(1),
 
         // Gensyms are instances of String (objects with identity).
         '%make-gensym': str => new String('S' + str),

diff --git a/test/string-eq.ss b/test/string-eq.ss
@@ -18,6 +18,8 @@
   (import (rnrs))
 
   (define (do-test)
-    (let ((x (list->string '(#\a #\b #\c))))
+    (let* ((x (list->string '(#\a #\b #\c)))
+           (y (string->symbol x)))
       (and (not (eq? x (list->string '(#\a #\b #\c))))
-           (eq? x x)))))
+           (eq? x x)
+           (eq? (symbol->string y) (symbol->string y))))))