A method to convert an NSSet to a list

programming-nu · Nov 28, 2010 · fa7e4b4 · fa7e4b4
1 parent 1ebb73c
commit fa7e4b4
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diff --git a/objc/extensions.h b/objc/extensions.h
@@ -77,6 +77,8 @@ limitations under the License.
 @interface NSSet(Nu)
 /*! Creates a set that contains the contents of a specified list. */
 + (NSSet *) setWithList:(id) list;
+/*! Convert a set into a list. */
+- (NuCell *) list;
 @end
 
 /*!

diff --git a/objc/extensions.m b/objc/extensions.m
@@ -164,6 +164,27 @@ + (NSSet *) setWithList:(id) list
     return s;
 }
 
+// Convert a set into a list.
+- (NuCell *) list
+{
+    NSEnumerator *setEnumerator = [self objectEnumerator];
+    NSObject *anObject = [setEnumerator nextObject];
+
+    if(!anObject)
+        return nil;
+
+    NuCell *result = [[[NuCell alloc] init] autorelease];
+    NuCell *cursor = result;
+    [cursor setCar:anObject];
+
+    while ((anObject = [setEnumerator nextObject])) {
+        [cursor setCdr:[[[NuCell alloc] init] autorelease]];
+        cursor = [cursor cdr];
+        [cursor setCar:anObject];
+    }
+    return result;
+}
+
 @end
 
 @implementation NSMutableSet(Nu)