Implement NSParagraph TabStops properly

Implement NSTextTab handling based on the GNUStep implementation,
with formatting and other adjustments.

AppKit/NSMutableParagraphStyle.m

@@ -128,17 +128,29 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
 }
 
 - (void) setTabStops: (NSArray *) tabStops {
-    tabStops = [tabStops copy];
-    [_tabStops release];
-    _tabStops = tabStops;
+    if (tabStops != _tabStops) {
+        [_tabStops removeAllObjects];
+        [_tabStops addObjectsFromArray: tabStops];
+        [_tabStops sortUsingSelector: @selector(compare:)];
+    }
 }
 
-- (void) addTabStop:(NSTextTab *) tabStop {
-    //NSUnimplementedMethod();
+- (void) addTabStop: (NSTextTab *) tabStop {
+    NSUInteger index = [_tabStops
+            indexOfObjectPassingTest: ^BOOL(NSTextTab *other, NSUInteger id,
+                                            BOOL *stop) {
+              return [other compare: tabStop] == NSOrderedAscending;
+            }];
+
+    if (index == NSNotFound) {
+        [_tabStops insertObject: tabStop atIndex: 0];
+    } else {
+        [_tabStops insertObject: tabStop atIndex: index];
+    }
 }
 
-- (void) removeTabStop:(NSTextTab *) tabStop {
-    //NSUnimplementedMethod();
+- (void) removeTabStop: (NSTextTab *) tabStop {
+    [_tabStops removeObject: tabStop];
 }
 
 - (void) setHyphenationFactor: (float) factor {

AppKit/NSParagraphStyle.m

@@ -34,7 +34,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
     return shared;
 }
 
-+ (NSWritingDirection)defaultWritingDirectionForLanguage:(NSString *)languageName {
++ (NSWritingDirection) defaultWritingDirectionForLanguage: (NSString *) languageName {
     NSUnimplementedMethod();
     return NSWritingDirectionNatural;
 }
@@ -74,7 +74,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
     _lineHeightMultiple = 0;
     _lineSpacing = 0;
     _defaultTabInterval = 0;
-    _tabStops = [[[self class] _defaultTabStops] retain];
+    _tabStops = [[[self class] _defaultTabStops] mutableCopy];
     _hyphenationFactor = 0;
     _tighteningFactorForTruncation = 0;
 }

AppKit/NSTextView.subproj/NSTextTab.m

@@ -136,4 +136,20 @@ NSString *NSTabColumnTerminatorsAttributeName =
     return self.location == other.location &&
            self.tabStopType == other.tabStopType;
 }
+
+- (NSComparisonResult) compare: (id) anObject {
+    CGFloat loc;
+
+    if (anObject == self)
+        return NSOrderedSame;
+    if (anObject == nil || ![anObject isKindOfClass: [self class]])
+        return NSOrderedAscending;
+    loc = ((NSTextTab *) anObject)->_location;
+    if (_location < loc)
+        return NSOrderedAscending;
+    else if (_location > loc)
+        return NSOrderedDescending;
+    else
+        return NSOrderedSame;
+}
 @end

AppKit/include/AppKit/NSMutableParagraphStyle.h

@@ -48,8 +48,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
 
 - (void) setDefaultTabInterval: (CGFloat) interval;
 - (void) setTabStops: (NSArray *) tabStops;
-- (void) addTabStop:(NSTextTab *) tabStop;
-- (void) removeTabStop:(NSTextTab *) tabStop;
+- (void) addTabStop: (NSTextTab *) tabStop;
+- (void) removeTabStop: (NSTextTab *) tabStop;
 
 
 - (void) setHyphenationFactor: (float) factor;

AppKit/include/AppKit/NSParagraphStyle.h

@@ -45,14 +45,14 @@ typedef enum {
     CGFloat _lineHeightMultiple;
     CGFloat _lineSpacing;
     CGFloat _defaultTabInterval;
-    NSArray *_tabStops;
+    NSMutableArray *_tabStops;
     float _hyphenationFactor;
     float _tighteningFactorForTruncation;
 }
 
 + (NSParagraphStyle *) defaultParagraphStyle;
 
-+ (NSWritingDirection)defaultWritingDirectionForLanguage:(NSString *)languageName;
++ (NSWritingDirection)defaultWritingDirectionForLanguage: (NSString *)languageName;
 
 - (NSWritingDirection) baseWritingDirection;
 

AppKit/include/AppKit/NSTextTab.h

@@ -49,4 +49,5 @@ APPKIT_EXPORT NSString *NSTabColumnTerminatorsAttributeName;
 
 - (CGFloat) location;
 
+- (NSComparisonResult) compare: (id) anObject;
 @end