Gain insights into Haskell's functional programming by learning to write pure functions, use pattern matching, recursion, and Lists, define data types, and execute IO operations.

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Functional programming is a problem-solving paradigm that differs drastically from the imperative programming style of languages like C++ or Java. While functional programming principles have invaded most modern programming languages to some degree, there is no language that embraces this paradigm quite as Haskell does. As a result, Haskell code can reach a level of expressiveness, safety, and elegance that is difficult to achieve in other programming languages.

This course will introduce you to the core concepts of functional programming in Haskell. You will learn how to write pure functions using techniques such as pattern matching and recursion, and how to work with Haskell's powerful List data type. You will understand the basics of Haskell's powerful type system and define your own data types. Finally, you’ll learn how to perform IO operations the Haskell way. By the end of this course, you’ll have a new paradigm to add under your belt and you can start using functional programming in your own projects.

Learn Functional Programming in Haskell

In this lesson we will take a look at another basic Haskell type: characters. Again, you can follow along with `ghci` from this terminal window:

# The `Char` type
The type `Char` represents single characters, such as letters or digits. Values of type `Char` are written in **single quotes** (e.g. `'a'`).  

There are a lot of useful predefined functions for characters. However, they are not in the **Prelude** module that is loaded by default, but in the module `Data.Char` of the Haskell standard library. To load this module in `ghci`, we can use the `import` directive.
```
Prelude> import Data.Char
Prelude Data.Char>
```
See how the prompt in `ghci` has changed, and now shows both `Prelude` and `Data.Char`. All of the functions of `Data.Char` are now available for use. Let's look at a few of them:

## Character classes

`Data.Char` contains many functions that check whether a given character is in a certain character class, e.g. letters or digits. They return boolean values.
```
Prelude Data.Char> isDigit 'a'
False
Prelude Data.Char> isLetter 'a'
True
Prelude Data.Char> isLower 'A'
False
```

## Encoding

We can encode characters as numeric character codes using `ord` and decode them using `chr`. The character encoding used is **Unicode**.

Explore the character data type in Haskell.

Introduction

First Steps with Haskell

Techniques for Writing Functions

Working with Lists

Creating Data Types

Input and Output

Conclusion

Appendix

Characters