Declared in NSOrderedSet+BlocksKit.h

Overview

Block extensions for NSOrderedSet.

Both inspired by and resembling Smalltalk syntax, these utilities allow for iteration through an ordered set (also known as a uniqued array) in a concise way that saves a ton of boilerplate code for filtering or finding objects.

Includes code by the following:

Tasks

  • – bk_each:

    Loops through an ordered set and executes the given block with each object.

  • – bk_apply:

    Enumerates through an ordered set concurrently and executes the given block once for each object.

  • – bk_match:

    Loops through an ordered set to find the object matching the block.

  • – bk_select:

    Loops through an ordered set to find the objects matching the block.

  • – bk_reject:

    Loops through an ordered set to to find the objects not matching the block.

  • – bk_map:

    Call the block once for each object and create an ordered set of the return values.

  • – bk_reduce:withBlock:

    Arbitrarily accumulate objects using a block.

  • – bk_any:

    Loops through an ordered set to find whether any object matches the block.

  • – bk_none:

    Loops through an ordered set to find whether no objects match the block.

  • – bk_all:

    Loops through an ordered set to find whether all objects match the block.

  • – bk_corresponds:withBlock:

    Tests whether every element of this ordered set relates to the corresponding element of another array according to match by block.

Instance Methods

bk_all:

- (BOOL)bk_all:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to find whether all objects match the block.

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

YES if the block returns YES for all objects in the ordered set, NO otherwise.

Declared In

NSOrderedSet+BlocksKit.h

bk_any:

- (BOOL)bk_any:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to find whether any object matches the block.

This method is similar to the Scala list exists. It is functionally identical to bk_match: but returns a BOOL instead. It is not recommended to use bk_any: as a check condition before executing bk_match:, since it would require two loops through the ordered set.

For example, you can find if a string in an ordered set starts with a certain letter:

 NSString *letter = @"A";
 BOOL containsLetter = [stringArray bk_any:^(id obj) {
     return [obj hasPrefix:@"A"];
 }];

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

YES for the first time the block returns YES for an object, NO otherwise.

Declared In

NSOrderedSet+BlocksKit.h

bk_apply:

- (void)bk_apply:(void ( ^ ) ( id obj ))block
Discussion

Enumerates through an ordered set concurrently and executes the given block once for each object.

Enumeration will occur on appropriate background queues. This will have a noticeable speed increase, especially on multi-core devices, but you must be aware of the thread safety of the objects you message from within the block. Be aware that the order of objects is not necessarily the order each block will be called in.

Parameters

block

A single-argument, void-returning code block.

Declared In

NSOrderedSet+BlocksKit.h

bk_corresponds:withBlock:

- (BOOL)bk_corresponds:(NSOrderedSet *)list withBlock:(BOOL ( ^ ) ( id obj1 , id obj2 ))block
Discussion

Tests whether every element of this ordered set relates to the corresponding element of another array according to match by block.

For example, finding if a list of numbers corresponds to their sequenced string values;

 NSArray *numbers = @[ @(1), @(2), @(3) ];
 NSArray *letters = @[ @"1", @"2", @"3" ];
 BOOL doesCorrespond = [numbers bk_corresponds:letters withBlock:^(id number, id letter) {
     return [[number stringValue] isEqualToString:letter];
 }];

Parameters

list

An array of objects to compare with.

block

A two-argument, BOOL-returning code block.

Return Value

Returns a BOOL, true if every element of the ordered set relates to corresponding element in another ordered set.

Declared In

NSOrderedSet+BlocksKit.h

bk_each:

- (void)bk_each:(void ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set and executes the given block with each object.

Parameters

block

A single-argument, void-returning code block.

Declared In

NSOrderedSet+BlocksKit.h

bk_map:

- (NSOrderedSet *)bk_map:(id ( ^ ) ( id obj ))block
Discussion

Call the block once for each object and create an ordered set of the return values.

This is sometimes referred to as a transform, mutating one of each object: NSOrderedSet *new = [stringArray bk_map:^id(id obj) { return [obj stringByAppendingString:@“.png”]); }];

Parameters

block

A single-argument, object-returning code block.

Return Value

Returns an ordered set of the objects returned by the block.

Declared In

NSOrderedSet+BlocksKit.h

bk_match:

- (id)bk_match:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to find the object matching the block.

bk_match: is functionally identical to bk_select:, but will stop and return on the first match.

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

Returns the object, if found, or nil.

See Also

Declared In

NSOrderedSet+BlocksKit.h

bk_none:

- (BOOL)bk_none:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to find whether no objects match the block.

This selector performs literally the exact same function as bk_all: but in reverse.

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

YES if the block returns NO for all objects in the ordered set, NO otherwise.

Declared In

NSOrderedSet+BlocksKit.h

bk_reduce:withBlock:

- (id)bk_reduce:(id)initial withBlock:(id ( ^ ) ( id sum , id obj ))block
Discussion

Arbitrarily accumulate objects using a block.

The concept of this selector is difficult to illustrate in words. The sum can be any NSObject, including (but not limited to) a string, number, or value.

For example, you can concentate the strings in an ordered set: NSString *concentrated = [stringArray bk_reduce:@“” withBlock:^id(id sum, id obj) { return [sum stringByAppendingString:obj]; }];

You can also do something like summing the lengths of strings in an ordered set: NSUInteger value = [[[stringArray bk_reduce:nil withBlock:^id(id sum, id obj) { return @([sum integerValue] + obj.length); }]] unsignedIntegerValue];

Parameters

initial

The value of the reduction at its start.

block

A block that takes the current sum and the next object to return the new sum.

Return Value

An accumulated value.

Declared In

NSOrderedSet+BlocksKit.h

bk_reject:

- (NSOrderedSet *)bk_reject:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to to find the objects not matching the block.

This selector performs literally the exact same function as bk_select: but in reverse.

This is useful, as one may expect, for removing objects from an ordered set to. NSOrderedSet *new = [computers bk_reject:^BOOL(id obj) { return ([obj isUgly]); }];

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

Returns an ordered set of all objects not found.

Declared In

NSOrderedSet+BlocksKit.h

bk_select:

- (NSOrderedSet *)bk_select:(BOOL ( ^ ) ( id obj ))block
Discussion

Loops through an ordered set to find the objects matching the block.

Parameters

block

A single-argument, BOOL-returning code block.

Return Value

Returns an ordered set of the objects found.

See Also

Declared In

NSOrderedSet+BlocksKit.h