# Dynamic vs Static Typing

By

Travis Horn

Dynamic and static typing are programming paradigms.

Dynamically typed languages don't have defined data types.

function add (x, y) {
	return x + y
}

add(1, 2)
// Returns 3

add(1, "hello")
// Returns "1hello"

The data types for the arguments x and y above are not defined. Although we may have designed this function to work on numbers only, it will also work on strings. This could produce unexpected behavior or errors at run-time.

Statically typed languages define the data types at compile-time and they cannot be changed during run-time.

add :: Integer -> Integer -> Integer
add x y = x + y

add 1 2
-- Returns 3

add 1 "World"
-- Error

The add function accepts two Integers and returns one Integer. Once compiled, it always will. If you try to pass an argument that is not an integer, the program will not compile.

Haskell is statically typed.