Renamed NSIndexPath+MPRemoveFirstIndex Category to NSIndexPath+MPReverseIndexPath

Added MPDisplayExtension Category to MPExpression and MPFunction
Added Methods to Invalidate the Cache to MPExpressionLayout and MPFunctionLayout

MathPad/MPDisplayExtension.h

@@ -0,0 +1,21 @@
+//
+//  MPExpression+MPDisplayExtension.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 23.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPModel.h"
+
+@interface MPExpression (MPDisplayExtension)
+
+- (void)subexpressionChangedAtRangePath:(MPRangePath *)rangePath;
+
+@end
+
+@interface MPFunction (MPDisplayExtension)
+
+- (void)subexpressionChangedAtRangePath:(MPRangePath *)rangePath;
+
+@end

MathPad/MPDisplayExtension.m

@@ -0,0 +1,33 @@
+//
+//  MPExpression+MPDisplayExtension.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 23.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPDisplayExtension.h"
+
+@implementation MPExpression (MPDisplayExtension)
+
+- (void)subexpressionChangedAtRangePath:(MPRangePath *)rangePath
+{
+    NSUInteger index = [self.parent indexOfChild:self];
+    NSIndexPath *newLocation = [rangePath.location indexPathByPrecedingIndex:index];
+    [self.parent subexpressionChangedAtRangePath:[[MPRangePath alloc] initWithLocation:newLocation
+                                                                                length:rangePath.length]];
+}
+
+@end
+
+@implementation MPFunction (MPDisplayExtension)
+
+- (void)subexpressionChangedAtRangePath:(MPRangePath *)rangePath
+{
+    NSUInteger index = [self.parent indexOfSymbol:self];
+    NSIndexPath *newLocation = [rangePath.location indexPathByPrecedingIndex:index];
+    [self.parent subexpressionChangedAtRangePath:[[MPRangePath alloc] initWithLocation:newLocation
+                                                                                length:rangePath.length]];
+}
+
+@end

MathPad/MPExpressionLayout.m

@@ -74,6 +74,7 @@
 - (void)invalidate
 {
     _valid = NO;
+    [self.parent invalidate];
 }
 
 - (void)expressionEditedInRange:(NSRange)range replacementLength:(NSUInteger)length
@@ -86,7 +87,7 @@
         [newPlaceholders addObject:[NSNull null]];
     }
     [_symbolCache replaceObjectsInRange:range withObjectsFromArray:newPlaceholders];
-    _valid = NO;
+    [self invalidate];
 }
 
 - (BOOL)hasCacheForSymbolAtIndex:(NSUInteger)index

MathPad/MPFunctionLayout.h

@@ -40,6 +40,7 @@
 #pragma mark Cache Methods
 
 - (void)invalidate;
+- (void)editedChildAtIndex:(NSUInteger)index;
 
 - (BOOL)hasCacheForChildAtIndex:(NSUInteger)index;
 - (MPExpressionLayout *)expressionLayoutForChildAtIndex:(NSUInteger)index;

MathPad/MPFunctionLayout.m

@@ -73,6 +73,15 @@
 - (void)invalidate
 {
     _valid = NO;
+    [self.parent invalidate];
+}
+
+- (void)editedChildAtIndex:(NSUInteger)index
+{
+    if ([self hasCacheForChildAtIndex:index]) {
+        _childCache[index] = [NSNull null];
+    }
+    [self invalidate];
 }
 
 - (BOOL)hasCacheForChildAtIndex:(NSUInteger)index

MathPad/MPModel.h

@@ -16,9 +16,10 @@
 #import "MPException.h"
 #import "MPExpression.h"
 #import "MPFunction.h"
+#import "MPRangePath.h"
 
 #import "NSObject+MPStringTest.h"
 #import "NSTextStorage+MPSetContents.h"
-#import "NSIndexPath+MPRemoveFirstIndex.h"
+#import "NSIndexPath+MPReverseIndexPath.h"
 
 #endif

MathPad/NSIndexPath+MPReverseIndexPath.h

@@ -0,0 +1,23 @@
+//
+//  NSIndexPath+MPRemoveFirstIndex.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 23.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface NSIndexPath (MPReverseIndexPath)
+
+/*!
+ @method indexPathByRemovingFirstIndex
+ @brief Provides an index path with the indexes in the receiving index path, excluding the first one.
+ @discussion Returns an empty NSIndexPath instance if the receiving index path’s length is 1 or less.
+ @return New index path with the receiving index path’s indexes, excluding the first one.
+ */
+- (NSIndexPath *)indexPathByRemovingFirstIndex;
+
+- (NSIndexPath *)indexPathByPrecedingIndex:(NSUInteger)index;
+
+@end

MathPad/NSIndexPath+MPReverseIndexPath.m

@@ -0,0 +1,37 @@
+//
+//  NSIndexPath+MPRemoveFirstIndex.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 23.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "NSIndexPath+MPReverseIndexPath.h"
+
+@implementation NSIndexPath (MPReverseIndexPath)
+
+- (NSIndexPath *)indexPathByRemovingFirstIndex
+{
+    if (self.length <= 1) {
+        return [[NSIndexPath alloc] init];
+    }
+    NSUInteger indexes[self.length];
+    [self getIndexes:indexes];
+    NSUInteger newIndexes[self.length-1];
+    for (NSUInteger i = 0; i < self.length-1; i++) {
+        newIndexes[i] = indexes[i+1];
+    }
+    return [[NSIndexPath alloc] initWithIndexes:newIndexes length:self.length-1];
+}
+
+- (NSIndexPath *)indexPathByPrecedingIndex:(NSUInteger)index
+{
+    NSUInteger newIndexes[self.length+1];
+    newIndexes[0] = index;
+    for (NSUInteger i = 0; i < self.length; i++) {
+        newIndexes[i+1] = [self indexAtPosition:i];
+    }
+    return [[NSIndexPath alloc] initWithIndexes:newIndexes length:self.length+1];
+}
+
+@end