1. 面向过程

面向过程：处理事情以过程为核心，一步一步的实现。

2. 面向对象

面向对象：万物皆对象。（封装、继承、多态）

3. 链式编程

链式编程：是将多个操作（多行代码）通过点号(.)链接在一起成为一句代码,使代码可读性好。a(1).b(2).c(3)

• 链式编程特点：方法的返回值是block,block必须有返回值（本身对象），block参数（需要操作的值）
• 代表：masonry框架。
• 模仿masonry，写一个加法计算器，练习链式编程思想。

    int iResult = [CaculatorMaker makeCaculators:^(CaculatorMaker * _Nonnull make) {
        make.add123(9).sub123(2).muilt123(3);
    }];
    NSLog(@"--%d--",iResult);

//CaculatorMaker.h

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface CaculatorMaker : NSObject

@property (nonatomic, assign) int iResult;

+ (int)makeCaculators:(void(^)(CaculatorMaker *make))caculatorMaker;

//加法
- (CaculatorMaker *(^)(int))add123;

//减法
- (CaculatorMaker *(^)(int))sub123;

//乘法
- (CaculatorMaker *(^)(int))muilt123;

//除法
- (CaculatorMaker *(^)(int))divide123;

@end

NS_ASSUME_NONNULL_END

//CaculatorMaker.m
#import "CaculatorMaker.h"

@implementation CaculatorMaker

+ (int)makeCaculators:(void (^)(CaculatorMaker * _Nonnull))caculatorMaker {
    CaculatorMaker *maker = [[CaculatorMaker alloc] init];
    caculatorMaker(maker);
    return maker.iResult;
}

- (CaculatorMaker * _Nonnull (^)(int))add123 {
    return ^CaculatorMaker *(int value) {
        self->_iResult += value;
        return self;
    };
}

- (CaculatorMaker * _Nonnull (^)(int))sub123 {
    return ^CaculatorMaker *(int value) {
        self->_iResult -= value;
        return self;
    };
}

- (CaculatorMaker * _Nonnull (^)(int))muilt123 {
    return ^CaculatorMaker *(int value) {
        self->_iResult *= value;
        return self;
    };
}

- (CaculatorMaker * _Nonnull (^)(int))divide123 {
    return ^CaculatorMaker *(int value) {
        self->_iResult /= value;
        return self;
    };
}

@end

4. 函数式编程 FP（Functional Programming）

• 函数式编程特点：每个方法必须有返回值（本身对象）,把函数或者Block当做参数,block参数（需要操作的值）block返回值（操作结果）
• 代表：ReactiveCocoa
• 用函数式编程实现，写一个加法计算器,并且加法计算器自带判断是否等于某个值.

    Caculator *c = [[Caculator alloc] init];
    BOOL isqule = [[[c caculator:^int(int result) {
        result += 2;
        result *= 5;
        return result;
    }] equle:^BOOL(int result) {
        return result == 10;
    }] isEqule];
    
//    BOOL isqule = [[c caculator:^int(int result) {
//        result += 2;
//        result *= 5;
//        return result;
//    }] equle:^BOOL(int result) {
//        return result == 10;
//    }].isEqule;
    
    NSLog(@"---%d",isqule);

//Caculator.h
#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface Caculator : NSObject

@property (nonatomic, assign) BOOL isEqule;
@property (nonatomic, assign) int result;

- (Caculator *)caculator:(int(^)(int result))caculator;
- (Caculator *)equle:(BOOL(^)(int result))operation;

@end

NS_ASSUME_NONNULL_END

//Caculator.m
#import "Caculator.h"

@implementation Caculator

- (Caculator *)caculator:(int (^)(int))caculator {
    self.result = caculator(0);
    return self;
}

- (Caculator *)equle:(BOOL (^)(int))operation {
    self.isEqule = operation(self.result);
    return self;
}

@end

5. 响应式编程 RP（Reactive Programming）

你变我也变

• 代表：KVO运用

6. 函数响应式编程 FRP ReactiveObjC

MVVM + RxSwift

block 返回值 ------链式编程 masonry
block 参数 ------函数式编程

参考