Documentation

First let's declare some values. In Integer is unbounded (or endless) integer value which does not depend on your computer's architecture so never overflows. The first line is a signature (`::` is a delimiter between a name and a type). The second line is a body.

>>> i + i == 84
True

An Int represents an integer which size respects your computer's architecture. Might overflow.

A single character

A String (technically, a list of Chars)

A Boolean, might be True or False

So, let's assume we know how to declare values, but what about functions? Functions and values are declared in a similar way, here we have a function which takes an Integer as a parameter and returns a Bool.

Values are functions which do not take any arguments!

>>> f 23
True

>>> f 19
False

This is a bit more sophisticated case: function takes two arguments.

>>> add 20 22
42

But what is we pass less arguments than needed? You get a function as a result!

>>> :t add 20
add 20 :: Integer -> Integer

>>> :t add
add :: Integer -> Integer -> Integer

This technique is called Currying

Another built-in type: a list. It has a special syntax

And, as it was mentioned a bit earlier, a String is a list of Chars.