const log = console.log; // zero :: &fa.a const zero = f => x => x; // zero is F // once :: &fa.fa const once = f => x => f(x); // once it I // twice :: &fa.f(fa) const twice = f => x => f(f(x)); // thrice :: &fa.f(f(fa))…

1. Functional programming treats computation as the evaluation of mathematical and avoids state and mutable data. Scala encourages an expression-oriented programming(EOP) 1) In expression-oriented programming every statement is an expression. A state…

Functions in Java Prior to the introduction of Lambda Expressions feature in version 8, Java had long been known as a purely object-oriented programming language. "Everything is an Object" is the philosophy deep in the language design. Objects a…

Java 8 发布带来的一个主要特性就是对函数式编程的支持. 而 Lambda 表达式就是一个新的并且很重要的一个概念. 它提供了一个简单并且很简洁的编码方式. 首先从几个简单的 Lambda 表达式的例子开始了解 Java 中的函数式编程. Lambda 表达式初识: 首先定义一个 Lambda 表达式: x -> x + 1 这个表达式输入参数是一个 x,然后对这个参数 x 的操作是加 1,然后将这个结果返回,即返回值. 从这个简单的 Lambda 表达式可以看出 Lambda 表达式的语法…

初学函数式编程,相信很多程序员兄弟们对于这个名字熟悉又陌生.函数,对于程序员来说并不陌生,编程对于程序员来说也并不陌生,但是函数式编程语言(Functional Programming language)又是什么呢?肯定很多朋友们也会有疑问. 学习一样东西,我们首先是了解他的历史,因为历史总是惊人低调相似,并让你从头到尾的了解它,让自己了解的更透彻. 在计算机的世界中,有两位巨擘对问题的可计算性做了模型化描述 一位是阿兰.图灵(Alan Turing),   图灵机,又称图灵计算.图灵计算机,是…

Lifting Now, let's review map from another perspective. map :: (T -> R) -> [T] -> [R] accepts 2 parameters, a function f :: T -> R and a list list :: [T]. [T] is a generic type paramterized by T, it's not the same as T, but definitely shares s…

background In pursuit of a real-world application, let’s say we need an e-commerce web applicationfor a mail-order coffee bean company. They sell several types of coffee and in differentquantities, both of which affect the price. Imperative methods F…

In computer science, functional programming is a programming paradigm, a style of building the structure and elements of computer programs, that treats computation as the evaluation of mathematical functions and avoids state and mutable data. It is a…

A functional programming function is like a mathematical function, which produces an output that typically depends only on its arguments. Each time a functional programming function is called with the same arguments, the same result is achieved. Func…

书籍: Functional Programming for Java Developers SICP(Structure and Interpretation of Computer Programs) 课程主页(有免费在线版):https://mitpress.mit.edu/sicp/ 视频教程:http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/ papers: Why Functional Pro…

In this blog post I will talk about the changes coming in Angular 2 that will improve its support for functional programming. Angular 2 is still in active development, so all the examples are WIP. Please focus on the capabilities and ideas, and not t…

It is really important to understand function signature in functional programming. The the code example below: const map = fn => anyFunctor => anyFunctor.map(fn); 'map' is pointfree version of any founctor's map, for example: Maybe.of('maybe').map(t…

今天开会提到了函数式编程,针对不同类型的百年城方式,查阅了一部分资料,展示如下: 编程语言一直到近代,从汇编到C到Java,都是站在计算机的角度,考虑CPU的运行模式和运行效率,以求通过设计一个高效的编程语言,作为人与计算机之间沟通的桥梁.因为计算机本质上是串行执行一个个指令流,因此编程语言也被设计为命令式编程(Imperative Programming),先算什么再算什么,怎么输入怎么计算怎么输出,全部由编程人员决定. 后来,大家发现冯·诺伊曼结构将数据和指令平等化的思想能够帮助我们更好地对…

引言 OK.时间非常快又过去了一周.第一周有五一假期所以感觉时间绰绰有余,这周中间没有假期仅仅能靠晚上加周末的时间来消化,事实上还是有点紧张呢! 后来发现每堂课的视频还有相应的课件(Slide).字幕(subtitles)能够下载.这样下载视频学习和在线学习就仅仅差课程中间的Exercise了 Week 2主要讲函数,函数在Scala里是first-class citizen,能够在随意域内出现.这门课事实上也是在借Scala来讲函数式编程原理. 好了,不多说.进入习题解析. 这周的作业主要是使…

In functional programming, a monad is a design pattern that defines how functions, actions, inputs, and outputs can be used together to build generic types,[1] with the following organization: Define a data type, and how values of that data type are…

函数式编程(Functional Programming), 函数式编程强调的函数:1.不依赖外部状态:2.不改变外部状态. 函数式编程可解决线程安全问题,每一个函数都是线程安全的. 时间状态:变量一旦有了状态,它就有可能随着时间而发生变化,时间是最不可预知的因素. 空间状态:如果把一个线程看成一个独立的空间,在程序的世界当中,空间会产生交叉重叠.一个变量如果可以被两个线程同时访问,它的值如果可以在两个空间发生变化,这个变量同样变得很危险 高阶函数:参数为函数或返回值为函数的函数: 实现一个计算…

Getting started with functional programming 开始函数式编程 higher-order functions-高阶函数 所有FP语言的主要特点是函数可以像普通值一样处理.它们可以存储到变量中,放入集合和结构中,作为参数传递给其他函数,并作为结果从其他函数返回. 将其他函数作为参数或返回新函数的函数称为高阶函数. 下面这两个模式在FP中很常见: filter: (collection<T>, (T → bool)) -> collection<…

Python Lambda & Functional Programming 函数式编程 匿名函数 纯函数 高阶函数 # higher-order functions def apply_twice(func, arg): return func(func(arg)) def add_five(x): return x + 5 print(apply_twice(add_five, 10)) # Pure function def pure_function(x, y): temp = x +…

JavaScript Functional Programming JavaScript 函数式编程 anonymous function https://en.wikipedia.org/wiki/Anonymous_function Lambda function https://en.wikipedia.org/wiki/Lambda_function http://en.wikipedia.org/wiki/Lambda_calculus Ramda v0.27.0 https://ra…

What is applicative functor: the ability to apply functors to each other. For example we have tow functors: Container(2), Container(3) // We can't do this because the numbers are bottled up. add(Container.of(), Container.of()); // NaN We cannot just…

什么是函数式编程 函数式编程是一种编程范式. 编程范式又是什么? 编程范式是一种解决问题的思路. 命令式编程 把程序看作 一系列改变状态的指令: 函数式编程 把程序看作 一系列数学函数映射的组合. i++; // 命令式 关心指令步骤 [i].map(x => x + 1); // 函数式 关心映射关系 函数式编程有什么好处 易写易读:聚焦重要逻辑,摆脱了循环之类的底层工作. 易复用:面向对象可复用单位是类,函数式可复用单位是函数,更小更灵活. 易测:纯函数[后面有写]不依赖外部环境,测试起来准…

函数编程(简称FP)不只代指Haskell Scala等之类的语言,还表示一种编程思维,软件思考方式,也称面向函数编程. 编程的本质是组合,组合的本质是范畴Category,而范畴是函数的组合. 首先,什么是函数式编程,这并没有唯一定义,它只是广泛聚合了一些编程风格的特性,我们可以将它与面向对象编程OOP进行对比, 两者区别是,OOP主要聚焦于数据的区别,而FP则注重数据结构的一致性. 面向对象: 数据和对数据的操作紧紧耦合 .对象隐藏它们操作的实现细节,其他对象调用这些操作只需要通过接口. .…

Learning notes. Video. Less than: If you use 'ramda', you maybe know 'lt, gt'.. R.lt(2, 1); //=> false Is '2' less than '1' , the result is false. We can see that the data is actually come first which is 2. Normally in FP, we want data come last. Wha…

Let's say we want to write a most simple implementation 'avg' function: const avg = list => { let sum = 0; for(let i = 0; i < list.length; i++) { sum += list[i] } return sum / list.length } Basiclly, the 'avg' function doing two things: Calculate su…

Imaging we have a deck of cards, eveytimes we need to pick one card from deck, the result we want to have is: // Selected: "A♠", // Remaining: [ "2♠", "3♠", "4♠", "5♠", "6♠", "7♠", &quo…

Recently, I am learning Working with ADT. Got some extra thought about State Monad. Basiclly how to thinking in State. First, we need to know the type of State: State returns Pair with Unit on the left, and state on the right: State(state => Pair(Uni…

print(abs(-10)) # 函数可以是变量 f = abs f(-10) def add(x,y,f): return f(x) + f(y) x = -5 y = 6 f = abs # 简单的函数式编程 print(add(x,y,f)) # 高阶函数 # map/reduce # map()函数接收两个参数,一个是函数,一个是Iterable,map将传入的函数依次作用到序列的每个元素,并把结果作为新的Iterator返回. def f(x): return x * x r = m…

Recentlly, I am learning crocks.js ADT libaray. In the beginning, it is hard to understand when to use 'runWith', 'evalWith', 'execWith'. Until I went though the coursea thrid times... I finally have some feelings for it. State has 'get, put, modify'…

Let's examine a pointfree way to write these applicative calls. Since we know map is equal to of/ap, we can write generic functions that will ap as many times as we specify: const liftA2 = curry((g, f1, f2) => f1.map(g).ap(f2)); const liftA3 = curry(…

Before we introduce what is Monad, first let's recap what is a pointed functor: A pointed functor is a Functor with .of() method Why pointed Functor is imporant? here OK, now, let's continue to see some code: const mmo = Maybe.of(Maybe.of('nunchucks'…