What is the formal difference in Scala between braces and parentheses, and when should they be used?

Question

What is the formal difference between passing arguments to functions in parentheses () and in braces {}?

The feeling I got from the Pro

Answer 1

With braces, you got semicolon induced for you and parentheses not. Consider takeWhile function, since it expects partial function, only {case xxx => ??? } is valid definition instead of parentheses around case expression.