517 lines
17 KiB
Objective-C
517 lines
17 KiB
Objective-C
//
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// MPExpression.h
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// MathPad
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//
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// Created by Kim Wittenburg on 10.08.14.
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// Copyright (c) 2014 Kim Wittenburg. All rights reserved.
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//
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@import Foundation;
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#import "NSString+MPExpressionElement.h"
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@class MPExpression, MPFunction, MPRangePath;
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@protocol MPExpressionElement;
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/*!
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@class MPExpression
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@brief An expression is the base object for any mathematical expression.
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@discussion Every expression consists of string elements (represented by the
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@c NSString class) and function (represented by the @c MPFunction
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class) elements which both can be contained within an expression.
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Functions in turn can have expressions as elements (also called
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'children' in this context). Both expressions and functions are
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mutable.
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Through this organization expression are organized in a tree-like
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structure (called the 'expression tree') allowing easy and
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logical access to each element.
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An expression can evaluate itself giving you either a
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result or possibly an error if the expression was not constructed
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correctly.
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*/
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@interface MPExpression : NSObject <NSCopying, NSCoding>
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#pragma mark Creation Methods
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/*!
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@method init
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@brief Initlializes a newly created expression.
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@discussion This method is a convenience initializer to initialize an empty
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expression.
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@return An expression.
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*/
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- (instancetype)init;
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/*!
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@method initWithElement:
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@brief Initializes a newly created expression with one element.
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@discussion This method is a convenience initializer to initialize an
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expression with a single element.
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@param element
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The element to be added to the expression. The @c element will be
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copied.
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@return An expression initialized with @c element.
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*/
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- (instancetype)initWithElement:(id<MPExpressionElement>)element;
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/*!
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@method initWithElements:
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@brief Initializes a newly created expression with the given elements.
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@discussion This method is the designated initializer for the @c MPExpression
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class.
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@param elements
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The elements that should be added to the expression. Each element
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is copied and the copy is then added to the expression.
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@return An expression containing the elements from @c elements.
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*/
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- (instancetype)initWithElements:(NSArray *)elements; /* designated initializer */
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#pragma mark Working With the Expression Tree
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/*!
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@property parent
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@brief The receiver's parent.
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@discussion Expressions are organized in a tree-like structure. Through this
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property an expression's containing function can be accessed.
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You should not set this property manually because that can cause
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inconsistencies in the expression tree.
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@return The parent of the receiver or @c nil if the receiver is the root
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expression.
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*/
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@property (nonatomic, weak) MPFunction *parent;
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/*!
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@method fixElements
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@brief Repairs any inconsistencies in the receiver.
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@discussion This method goes over all elements in the receiver and tries to
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repair inconsistencies that occured when mutating the receiver.
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Since this method is called automatically everytime the receiver
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is mutated there should be little need for you to call it
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yourself.
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*/
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- (void)fixElements;
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#pragma mark Primitive Methods
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/*!
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@method length
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@brief Returns the length of the receiver.
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@discussion The length of an expression is calculated by walking over each
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element in the receiver and sending it a @c length message. This
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method should be used to determine the number of digits or
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symbols in an expression.
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To address a symbol in the expression counted in the @c length
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reference frame of an expression the word 'location' is used.
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@return The length of the receiver. This is the number of symbols in all
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elements in the receiver where a function element is counted as a
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single symbol.
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*/
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- (NSUInteger)length;
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/*!
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@method numberOfElements
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@brief Returns the number of elements in the receiver.
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@discussion The number of elements may vary from the number of elements that
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were added to the receiver (using either @c -initWithElements: or
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@ -replaceElementsInRange:withElements:)
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To address a specific symbol in an expression the word 'index' is
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used. The index of elements is used when you access an
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expression's elements using subscript syntax.
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@return The current number of elements in the receiver.
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*/
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- (NSUInteger)numberOfElements;
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/* Subscripting is supported for indexes and elements */
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- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx;
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- (id)objectAtIndexedSubscript:(NSUInteger)idx;
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/*!
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@method elementAtIndex:
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@brief Returns the element at @c anIndex.
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@discussion The element is not copied before it is returned. So be aware that
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if you mutate a @c MPFunction object returned from this function
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the changes will be reflected in the receiver.
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This method can also be called using indexed subscript getter
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syntax.
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@param anIndex
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The index of the element. If the index is greater than or equal
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to the number of elements in the receiver an @c NSRangeException
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is raised.
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@return The element located at @c anIndex.
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*/
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- (id<MPExpressionElement>)elementAtIndex:(NSUInteger)anIndex;
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/*!
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@method elementsInRange:
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@brief Returns an array of the elements that are located in the
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specified range. The range is specified in indexes.
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@discussion The objects in the returned array are not copied before they are
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returned. You should be aware of the fact that mutations to any
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returned element will be reflected in the receiver.
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If the @c range exceeds the receiver's bounds an @c
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NSRangeException is raised.
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@param range
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The requested range within the receiver's bounds.
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@return An array of objects that conform to the @c MPExpressionElement
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protocol (that is @c NSString objects and @c MPFunction objects).
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The length of the returned array is equal to the length of the
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specified range.
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*/
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- (NSArray *)elementsInRange:(NSRange)range;
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/*!
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@method indexOfElement:
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@brief Returns the index of @c element or @c NSNotFound if it was not
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found.
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@discussion
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@param
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@return
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*/
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#warning Implementation may be faulty
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- (NSUInteger)indexOfElement:(id<MPExpressionElement>)element;
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/*!
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@method replaceSymbolsInRange:withElements:
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@brief Replaces the elements in the given range with the contents of the
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@c elements array.
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@discussion This is the most primitive mutation method of @c MPExpression.
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Every other mutating method utlimately must call this method.
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After the receiver has been mutated @c -fixElements is called to
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restore integrity of the receiver.
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After the receiver has been mutated (and integrity has been
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restored) the receiver sends a @c
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-didChangeElementsInRangePath:replacementLength: to itself. For
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more information see the documentation on that method.
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@param range
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The @c range is specified in the length reference
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frame. Because of this this method can be directly used for user
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interaction.
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@param elements
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The elements that should replace the symbols specified by @c
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range.
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*/
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- (void)replaceSymbolsInRange:(NSRange)range
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withElements:(NSArray *)elements;
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// TODO: - (NSUInteger)indexOfElementAtSymbolLocation:(NSUInteger)location;
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#warning Evaluating must possibly return error
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- (double)doubleValue; // Evaluates Expression
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#pragma mark Notifications
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// All notification methods should create a new rangePath with the receiver's index added to the beginning of the path and then ascend the message to it's parent
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// TODO: More notifications
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/*!
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@method didChangeElementsInRangePath:replacementLength:
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@brief Called after the receiver has been mutated.
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@discussion This method does nothing more than notify it's parent that it has
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been mutated at the receiver's index. If you need to know about
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changes in an expression you should override this method instead
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of @c -replaceSymbolsInRange:withElements because this method
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gives you information about the number of elements changed during
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the mutation.
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@param rangePath
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The range path at which the receiver was changed starting at the
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receiver.
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@param replacementLength
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The number of elements replacing the elements specified by @c
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rangePath.
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*/
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- (void)didChangeElementsInRangePath:(MPRangePath *)rangePath
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replacementLength:(NSUInteger)replacementLength;
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#pragma mark Basic NSObject Methods
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/*!
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@method isEqualToExpression:
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@brief Returns wether the receiver is equal to @c anExpression.
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@param anExpression
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The expression the receiver should be compared to.
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@return @c YES if @c anExpression is equal to the receiver, @c NO
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otherwise.
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*/
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- (BOOL)isEqualToExpression:(MPExpression *)anExpression;
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- (NSString *)description;
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- (NSUInteger)hash;
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@end
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/* --------------------------------------------------------------------------- */
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/* Extension Methods */
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/* --------------------------------------------------------------------------- */
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@interface MPExpression (MPExpressionExtension)
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#pragma mark Working With the Expression Tree
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/*!
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@method elementAtIndexPath:
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@brief Returns the element at the specified index path.
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@discussion The returned object can be an @c NSString, a @c MPFunction or an
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@c MPExpression depending on the element @c indexPath points to.
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If any of the indexes exceed the bounds of the respective
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receiver an @c NSRangeException is raised.
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If the index path does not contain any indexes the receiver
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itself is returned.
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@param indexPath
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The index path the required object is located at.
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@return The element located at @c indexPath. The element is not copied
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before it is returned. Be aware of the fact that any mutations
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made to the returned object are reflected in the receiver.
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*/
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- (id)elementAtIndexPath:(NSIndexPath *)indexPath;
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/*!
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@method elementsInRangePath:
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@brief Returns the elements in the specified range path.
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@discussion If any of the indexes or the range exceed the bounds of the
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respective receiver an @c NSRangeException is raised.
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@param rangePath
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The range path the requested objects are located at.
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@return An array of objects specified by the range path. The returned
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elements are not copied before they are returned. Be aware that
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any mutations made to the returned objects are reflected in the
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receiver.
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*/
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- (NSArray *)elementsInRangePath:(MPRangePath *)rangePath;
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/*!
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@method indexPath
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@brief Returns the index path of the receiver in the expression tree.
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@discussion The index path is calculated by walking up the expression tree
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collecting the respective index of the receiver.
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@return The index path of the receiver in the expression tree.
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*/
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- (NSIndexPath *)indexPath;
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#pragma mark Working With Expressions
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/*!
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@method subexpressionFromLocation:
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@brief Creates a new expression from the specified index (inclusive) to
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the end of the receiver.
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@discussion The elements in the newly created expression are copied to the
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new expression. The location is specified in the length reference
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frame.
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If the given location exceeds the receiver's bounds a @c
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NSRangeException is raised.
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@param from
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The first location to be included in the new expression.
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@return A new expression.
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*/
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- (MPExpression *)subexpressionFromLocation:(NSUInteger)from;
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/*!
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@method subexpressionToLocation:
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@brief Creates a new expression from the beginning to the specified
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index (exclusive).
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@discussion The elements in the newly created expression are copied to the
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new expression. The location is specified in the length reference
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frame.
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If the given location exceeds the receiver's bounds a @c
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NSRangeException is raised.
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@param to
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The first location not to be included in the new expression or
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the length of the new expression.
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@return A new expression.
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*/
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- (MPExpression *)subexpressionToLocation:(NSUInteger)to;
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/*!
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@method subexpressionWithRange:
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@brief Creates a new expression with the symbols in the specified range.
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@discussion The elements in the newly created expression are copied to the
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new exoression. The range is specified in the length reference
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frame.
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If the given range exceeds the receiver's bounds a @c
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NSRangeException is raised.
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@param range
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The range from which to create the new expression.
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@return A new expression.
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*/
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- (MPExpression *)subexpressionWithRange:(NSRange)range;
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#pragma mark Mutating Expressions
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/*!
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@method appendElement:
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@brief Appends @c anElement to the receiver.
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@param anElement
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The element to append to the receiver.
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*/
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- (void)appendElement:(id<MPExpressionElement>)anElement;
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/*!
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@method appendElements:
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@brief Appends the objects from @c elements to the receiver.
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@param elements
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The elements to append to the receiver.
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*/
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- (void)appendElements:(NSArray *)elements;
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/*!
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@method insertElement:atLocation:
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@brief Inserts @c anElement at @c location.
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@discussion The location is specified in the length reference frame.
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If the given location exceeds the receiver's bounds a @c
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NSRangeException is raised.
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@param anElement
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The element to be inserted into the receiver.
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@param location
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The location @c anElement should be inserted at.
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*/
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- (void)insertElement:(id<MPExpressionElement>)anElement
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atLocation:(NSUInteger)location;
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/*!
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@method insertElements:atLocation:
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@brief Inserts the elements from @c elements at @c location.
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@discussion The location is specified in the length reference frame.
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If the given location exceeds the receiver's bounds a @c
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NSRangeException is raised.
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@param elements
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The elements to be inserted into the receiver.
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@param location
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The location the elements in @c elements should be inserted into
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the receiver.
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*/
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- (void)insertElements:(NSArray *)elements
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atLocation:(NSUInteger)location;
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/*!
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@method deleteElementsInRange:
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@brief Removes the elements specified by @c range from the receiver.
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@discussion The range is specified in the length reference frame.
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If @c range exceeds the receiver's bounds a @c NSRangeException
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is raised.
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@param range
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The range to remove from the receiver.
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*/
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- (void)deleteElementsInRange:(NSRange)range;
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#pragma mark Querying Expressions
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/*!
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@method elements
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@brief Returns an array of all elements in the receiver.
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@discussion The elements in the returned array are not copied before they are
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returned.
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@return An array of all elements from the receiver.
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*/
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- (NSArray *)elements;
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// TODO: - (NSMutableArray *)mutableElements;
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@end
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