Code Style Terminology

LINQ-style

Chained functional operations on collections:

strings.filter { it.length == 5 }
    .sortedBy { it }
    .map { it.toUpperCase() }

Pure Function

A function whose return value is completely dependent on its arguments/parameters with no side effects.

fun square(n: Int): Int {
    return n * n
}

High-Order Function

Functions that take another function as an argument or return a function as result.

fun highOrderFunc(a: Int, validityCheckFunc: (a: Int) -> Boolean) {
    if (validityCheckFunc(a)) {
        println("a $a is Valid")
    } else {
        println("a $a is Invalid")
    }
}

fun main(args: Array<String>) {
    highOrderFunc(12, { a: Int -> a.isEven() })
    highOrderFunc(19, { a: Int -> a.isEven() })
}

Programming Paradigms

Imperative Programming

Allows side effects

  • Used in contrast to declarative programming
  • Uses statements that change a program’s state
  • Implements algorithms in explicit steps (control flow)

Declarative Programming

Does not state the order in which operations execute

  • Express the logic without describing its control flow
  • Many languages attempt to minimize or eliminate side effects
  • Describes what the program must accomplish rather than how to accomplish it
  • Greatly simplifies writing parallel programs
  • Examples: SQL, regular expressions, logic programming, functional programming

Logic Programming

  • Languages include Prolog, Answer Set Programming (ASP), and Datalog
  • A set of sentences in logical form, expressing facts and rules about some problem domain
  • Rules are written in the form of clauses

Functional Programming

Disallows side effects

  • Avoids changing state and mutable data (original values are not modified during processing)
  • Output value of a function depends only on the arguments passed (pure functions)
  • One form of declarative programming
  • Allows dependency distribution

Reactive Programming

  • Like Excel, when a value changes, all referencing values update
  • Based on Observable and Observer pattern

IT Terminology

On-Premise

Operating software solutions on your own servers in your own data center, rather than in a cloud or remote environment.

Concurrency

Semaphore

A method to limit access to shared resources in a multiprogramming environment.

  • Prevents more processes from accessing a resource than it can handle
  • If there is only 1 resource, only one thread can process at a time
  • Other threads must wait

Financial Terminology

Portfolio

A collection of assets. In investing, a list of diversified investment assets.

Loan Terms

Term Meaning
Repayment Returning borrowed money
Principal The original loan amount
NPA (Non-Performing Asset) A loan in default