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…
1. The three principles of OOP are encapsulation(封装性), inheritance(继承性) and polymorphism(多态性). example: class Shape{ def area: Double = 0.0 } # supertype # subtypes class Rectangle(val width: Double, val height: Double) extends Shape{ override def ar…
1. Scala is a contraction of "scalable" and "language". It's a fusion of objected-oritended and functional programming. 2. Compare Book class between Java and Scala Java: class Book{ private String title; private int numberOfPages; pub…
Scala's object-oriented collections support mutable and immutable type hierarchies. Also support functional higher-order operations such as map, filter, and reduce that let you use expression-oriented programming in collections. Higher-order operatio…
1. Translating Java Classes to Scala Classes Example 1: # a class declaration in Java public class Book{} # Scala equivalent of a class declaration class Book Example 2: # a Java class with a Construtor public class Book{ private final int isbn; priv…
The basic functional cornerstones of Scala: immutable data types, passing of functions as parameters and pattern matching. 1. Basic Pattern Matching In Scala, your cases can include types, wildcards, sequences, regular expressions, and so forth. scal…
1. Variables (1) Three ways to define variables: 1) val refers to define an immutable variable; scala> val x = x: Int = scala> x*x res4: Int = scala> res4 + # use result as a value res6: Int = scala> res4 + res6 res7: Int = scala> x = # x i…
1. Unified Type System Scala has a unified type system, enclosed by the type Any at the top of the hierarchy and the type Nothing at the bottom of the hierarchy. All Scala types inherit from Any. # Using Any, Book extends AnyRef, and x is an Int that…
A trait provides code reusability in Scala by encapsulating method and state and then offing possibility of mixing them into classes thus allowing code reuse. #define Trait Gliding scala> trait Gliding{ | def gliding(){ println("gliding")} |…
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…
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…
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…
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…
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…
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…
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…
