2.2.1 Simple Statement

Statements are of two types: simple and compound, just like simple and compound sentences in a natural language such as English. The statement

$celsius = 5/9 * ($fahrenheit - 32);

is a simple statement. A simple statement can be considered an expression that has one or more side effects. In this case, the side effect is assigning a value to the variable $temperature.
A simple statement is like a simple sentence in English. A simple statement is independently executable. It is a minimal piece of independently executable code ended by a ;. Assignment statements are simple statements. Other examples of simple statements are subroutine calls, and returns from subroutines. We see them in Chapter 12 on functional programming. There is a class of simple statements that allow one to exit a program or a part of a program such as a loop, either normally or abnormally. These include statements such as die, warn, next, redo, and last. We see some of them later in this chapter.