  ![Next page: Introduction to evaluation order [Section] -- Keyboard shortcut: 'n'](./images/nav-right.gif "Next page: Introduction to evaluation order [Section] -- Keyboard shortcut: 'n'")        | Lecture 5 - Page 3 : 26 |
| Functional Programming in Scheme The Order of Evaluation |
|
|
| An illustration of referential transparency |
With referential transparency it is possible to perform natural program transformations without
any concern of side effects |
 | It is possible to rewrite one of the expressions above to the other, provided that F is a function.
Below, we have illustrated an example where F is of procedural nature. Notice that F assigns the variable
c, such that it becomes critical to know how many times F is called. |