return-from operator

programming-nu · Nov 25, 2010 · 1ebb73c · 1ebb73c
1 parent 3c27800
commit 1ebb73c
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Showing 4 changed files with 57 additions and 3 deletions.
diff --git a/objc/block.m b/objc/block.m
@@ -158,6 +158,9 @@ - (id) callWithArguments:(id)cdr context:(NSMutableDictionary *)calling_context
     }
     @catch (NuReturnException *exception) {
         value = [exception value];
+		if ([exception blockForReturn] && ([exception blockForReturn] != self)) {
+			@throw(exception);
+		}
     }
     @catch (id exception) {
         @throw(exception);
@@ -230,6 +233,9 @@ - (id) evalWithArguments:(id)cdr context:(NSMutableDictionary *)calling_context
     }
     @catch (NuReturnException *exception) {
         value = [exception value];
+		if ([exception blockForReturn] && ([exception blockForReturn] != self)) {
+			@throw(exception);
+		}
     }
     @catch (id exception) {
         @throw(exception);

diff --git a/objc/nuinternals.h b/objc/nuinternals.h
@@ -52,9 +52,11 @@ limitations under the License.
 @interface NuReturnException : NSException
 {
     id value;
+	id blockForReturn;
 }
 
 - (id) value;
+- (id) blockForReturn;
 @end
 
 // use this to test a value for "truth"

diff --git a/objc/operator.m b/objc/operator.m
@@ -53,11 +53,20 @@ - (id) init
 @end
 
 @implementation NuReturnException
-- (id) initWithValue:(id) v;
+- (id) initWithValue:(id) v
 {
     [super initWithName:@"NuReturnException" reason:@"A return operator was evaluated" userInfo:nil];
     value = [v retain];
-    return self; ;
+    blockForReturn = nil;
+    return self;
+}
+
+- (id) initWithValue:(id) v blockForReturn:(id) b
+{
+    [super initWithName:@"NuReturnException" reason:@"A return operator was evaluated" userInfo:nil];
+    value = [v retain];
+    blockForReturn = b;                           // weak reference
+    return self;
 }
 
 - (void) dealloc
@@ -71,6 +80,11 @@ - (id) value
     return value;
 }
 
+- (id) blockForReturn
+{
+    return blockForReturn;
+}
+
 @end
 
 @implementation NuOperator : NSObject
@@ -2007,6 +2021,29 @@ - (id) callWithArguments:(id)cdr context:(NSMutableDictionary *)context
 
 @end
 
+@interface Nu_return_from_operator : NuOperator {}
+@end
+
+@implementation Nu_return_from_operator
+
+- (id) callWithArguments:(id)cdr context:(NSMutableDictionary *)context
+{
+    id block = nil;
+    id value = nil;
+    id cursor = cdr;
+    if (cursor && cursor != Nu__null) {
+        block = [[cursor car] evalWithContext:context];
+        cursor = [cursor cdr];
+    }
+    if (cursor && cursor != Nu__null) {
+        value = [[cursor car] evalWithContext:context];
+    }
+    @throw [[[NuReturnException alloc] initWithValue:value blockForReturn:block] autorelease];
+    return nil;                                   // unreached
+}
+
+@end
+
 @interface Nu_version_operator : NuOperator {}
 @end
 
@@ -2160,6 +2197,7 @@ void load_builtins(NuSymbolTable *symbolTable)
     install("break",    Nu_break_operator);
     install("continue", Nu_continue_operator);
     install("return",   Nu_return_operator);
+    install("return-from",   Nu_return_from_operator);
 
     install("try",      Nu_try_operator);
 

diff --git a/test/test_return.nu b/test/test_return.nu
@@ -50,4 +50,12 @@
         (assert_equal "positive" (rtc sign:1))
         (assert_equal "-" (ReturnTestClass sign:-1))
         (assert_equal "0" (ReturnTestClass sign:0))
-        (assert_equal "+" (ReturnTestClass sign:1))))
+        (assert_equal "+" (ReturnTestClass sign:1)))
+
+     (- testReturnFromOperator is
+        (set outer (do ()
+                       (10 times:
+                           (do (i) (10 times:
+                                       (do (j) (if (and (eq i 3) (eq j 4))
+                                                   (return-from outer (+ i j)))))))))
+        (assert_equal 7 (outer))))