Block & Expression Body

Is there a difference really?

Yes in Kotlin you can represent functions in more than one way.

In Block the function body is inside braces {}

In Expressions the function body is declared as an expression

Let's see how we can declare a function that adds two numbers in more than one way.

fun add( a:Int, b:Int) : Int {
    return a + b
}

Notice the function body is inside braces {}.

fun add(a:Int, b:Int) = a + b

The function can be expressed in one line since the expression a + b has a value. The return type is also infered so you don't have to specify it.

Before we go about benefits we should remember that

As developers we'll read more code than write

So wouldn't it be helpful if we could express a lot of information but with the fewest words possible? (I know you're nodding in agreement 😆😆)

Kotlin aims at being concise, give a lot of information with few words.

Expression body functions do just that, you can declare what the function should do without a lot of boilerplate, hence making reading faster 😉 😉

caution

Expression body functions can only be used with expressions such as if, when or try, they cannot be used with statements.
Removing the return type only works for functions with expression body, block body functions have to specify the return type and use the keyword return

Check out other bits and try to guess if the functions have block or expression bodies, don't forget to add a reaction below or comment 😉 😉...