Haskell is a functional programming language that has been around for over three decades. It was named after the mathematician Haskell Curry, and it has been designed to be both expressive and concise. Haskell is known for its strong type system, lazy evaluation, and the ability to write code that is both concise and expressive. In this guide, we will introduce you to the basics of Haskell programming, how to write it with an example, and the best applications for it.

Getting Started with Haskell:

Before we dive into writing code, let's first discuss how to get started with Haskell programming. Haskell is a compiled language, which means that you need to install a compiler to run Haskell code. There are several Haskell compilers available, including GHC (Glasgow Haskell Compiler), Hugs, and nhc98. We recommend using GHC, which is the most popular Haskell compiler and is available on most platforms.

Once you have installed the GHC compiler, you can start writing Haskell code using a text editor or an Integrated Development Environment (IDE). Some popular text editors for Haskell include Emacs, Vim, and Atom. There are also several IDEs available for Haskell, including Leksah, EclipseFP, and Haskell for Mac.

Writing Haskell Code:

Haskell code is typically organized into modules, which are collections of related functions and data types. The basic syntax of Haskell is similar to that of other programming languages, with functions being defined using the "function name + argument list + function body" structure. Haskell functions can be defined using the keyword "let," and can be called using the function name followed by the arguments.

Here's an example of a simple Haskell program that takes two integers as input and returns their sum:

```
module Main where

main :: IO ()
main = do
  putStrLn "Enter the first number: "
  num1 <- getLine
  putStrLn "Enter the second number: "
  num2 <- getLine
  let sum = (read num1) + (read num2)
  putStrLn ("The sum is: " ++ show sum)
```

In this program, we define a main function that prompts the user to enter two numbers, reads them from the console using the `getLine` function, computes their sum using the `let` keyword, and displays the result using the `putStrLn` function.

Best Applications for Haskell:

Haskell is a powerful programming language that is well-suited for a wide range of applications. Some of the most common applications of Haskell include:

1. Data analysis and machine learning: Haskell's strong type system and lazy evaluation make it well-suited for data analysis and machine learning tasks.

2. Web development: Haskell has a number of web development frameworks, such as Yesod and Snap, that make it easy to build web applications.

3. Financial modeling: Haskell's ability to handle complex mathematical operations makes it ideal for financial modeling and analysis.

4. Scientific computing: Haskell is increasingly being used in scientific computing applications, such as physics and chemistry simulations.

Conclusion:

Haskell is a powerful and expressive programming language that is well-suited for a wide range of applications. In this guide, we introduced you to the basics of Haskell programming, including how to write Haskell code and the best applications for it. We hope that this guide has provided you with a solid foundation to start exploring the world of Haskell programming.