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| <a name="Deviations-from-Standard-Modula_002d2"></a> |
| <h4 class="subsubsection">15.4.8.6 Deviations from Standard Modula-2</h4> |
| <a name="index-Modula_002d2_002c-deviations-from"></a> |
| |
| <p>A few changes have been made to make Modula-2 programs easier to debug. |
| This is done primarily via loosening its type strictness: |
| </p> |
| <ul> |
| <li> Unlike in standard Modula-2, pointer constants can be formed by |
| integers. This allows you to modify pointer variables during |
| debugging. (In standard Modula-2, the actual address contained in a |
| pointer variable is hidden from you; it can only be modified |
| through direct assignment to another pointer variable or expression that |
| returned a pointer.) |
| |
| </li><li> C escape sequences can be used in strings and characters to represent |
| non-printable characters. <small>GDB</small> prints out strings with these |
| escape sequences embedded. Single non-printable characters are |
| printed using the ‘<samp>CHR(<var>nnn</var>)</samp>’ format. |
| |
| </li><li> The assignment operator (<code>:=</code>) returns the value of its right-hand |
| argument. |
| |
| </li><li> All built-in procedures both modify <em>and</em> return their argument. |
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