Statements and expressions

Abstract

The specification of an action is called a statement Statements can be interpreted (executed), and that interpretation (execution) has an effect. The effect is a transformation of the state of the computation, the state being represented by the collective values of the program’s variables. The most elementary action is the assignment of a value to a variable. The assignment statement has the form $ assignment = designator “: = ” expression. and its corresponding action consists of three parts in this sequence:

• 1 evaluate the designator designating a variable,

• 2 evaluate the expression yielding a value,

• 3 replace the value of the variable identified in 1. by the value obtained in 2.