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  57. <a name="Built_002dIn-Func_002fProc"></a>
  58. <div class="header">
  59. <p>
  60. Next: <a href="M2-Constants.html#M2-Constants" accesskey="n" rel="next">M2 Constants</a>, Previous: <a href="M2-Operators.html#M2-Operators" accesskey="p" rel="prev">M2 Operators</a>, Up: <a href="Modula_002d2.html#Modula_002d2" accesskey="u" rel="up">Modula-2</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
  61. </div>
  62. <hr>
  63. <a name="Built_002din-Functions-and-Procedures"></a>
  64. <h4 class="subsubsection">15.4.9.2 Built-in Functions and Procedures</h4>
  65. <a name="index-Modula_002d2-built_002dins"></a>
  66. <p>Modula-2 also makes available several built-in procedures and functions.
  67. In describing these, the following metavariables are used:
  68. </p>
  69. <dl compact="compact">
  70. <dt><var>a</var></dt>
  71. <dd><p>represents an <code>ARRAY</code> variable.
  72. </p>
  73. </dd>
  74. <dt><var>c</var></dt>
  75. <dd><p>represents a <code>CHAR</code> constant or variable.
  76. </p>
  77. </dd>
  78. <dt><var>i</var></dt>
  79. <dd><p>represents a variable or constant of integral type.
  80. </p>
  81. </dd>
  82. <dt><var>m</var></dt>
  83. <dd><p>represents an identifier that belongs to a set. Generally used in the
  84. same function with the metavariable <var>s</var>. The type of <var>s</var> should
  85. be <code>SET OF <var>mtype</var></code> (where <var>mtype</var> is the type of <var>m</var>).
  86. </p>
  87. </dd>
  88. <dt><var>n</var></dt>
  89. <dd><p>represents a variable or constant of integral or floating-point type.
  90. </p>
  91. </dd>
  92. <dt><var>r</var></dt>
  93. <dd><p>represents a variable or constant of floating-point type.
  94. </p>
  95. </dd>
  96. <dt><var>t</var></dt>
  97. <dd><p>represents a type.
  98. </p>
  99. </dd>
  100. <dt><var>v</var></dt>
  101. <dd><p>represents a variable.
  102. </p>
  103. </dd>
  104. <dt><var>x</var></dt>
  105. <dd><p>represents a variable or constant of one of many types. See the
  106. explanation of the function for details.
  107. </p></dd>
  108. </dl>
  109. <p>All Modula-2 built-in procedures also return a result, described below.
  110. </p>
  111. <dl compact="compact">
  112. <dt><code>ABS(<var>n</var>)</code></dt>
  113. <dd><p>Returns the absolute value of <var>n</var>.
  114. </p>
  115. </dd>
  116. <dt><code>CAP(<var>c</var>)</code></dt>
  117. <dd><p>If <var>c</var> is a lower case letter, it returns its upper case
  118. equivalent, otherwise it returns its argument.
  119. </p>
  120. </dd>
  121. <dt><code>CHR(<var>i</var>)</code></dt>
  122. <dd><p>Returns the character whose ordinal value is <var>i</var>.
  123. </p>
  124. </dd>
  125. <dt><code>DEC(<var>v</var>)</code></dt>
  126. <dd><p>Decrements the value in the variable <var>v</var> by one. Returns the new value.
  127. </p>
  128. </dd>
  129. <dt><code>DEC(<var>v</var>,<var>i</var>)</code></dt>
  130. <dd><p>Decrements the value in the variable <var>v</var> by <var>i</var>. Returns the
  131. new value.
  132. </p>
  133. </dd>
  134. <dt><code>EXCL(<var>m</var>,<var>s</var>)</code></dt>
  135. <dd><p>Removes the element <var>m</var> from the set <var>s</var>. Returns the new
  136. set.
  137. </p>
  138. </dd>
  139. <dt><code>FLOAT(<var>i</var>)</code></dt>
  140. <dd><p>Returns the floating point equivalent of the integer <var>i</var>.
  141. </p>
  142. </dd>
  143. <dt><code>HIGH(<var>a</var>)</code></dt>
  144. <dd><p>Returns the index of the last member of <var>a</var>.
  145. </p>
  146. </dd>
  147. <dt><code>INC(<var>v</var>)</code></dt>
  148. <dd><p>Increments the value in the variable <var>v</var> by one. Returns the new value.
  149. </p>
  150. </dd>
  151. <dt><code>INC(<var>v</var>,<var>i</var>)</code></dt>
  152. <dd><p>Increments the value in the variable <var>v</var> by <var>i</var>. Returns the
  153. new value.
  154. </p>
  155. </dd>
  156. <dt><code>INCL(<var>m</var>,<var>s</var>)</code></dt>
  157. <dd><p>Adds the element <var>m</var> to the set <var>s</var> if it is not already
  158. there. Returns the new set.
  159. </p>
  160. </dd>
  161. <dt><code>MAX(<var>t</var>)</code></dt>
  162. <dd><p>Returns the maximum value of the type <var>t</var>.
  163. </p>
  164. </dd>
  165. <dt><code>MIN(<var>t</var>)</code></dt>
  166. <dd><p>Returns the minimum value of the type <var>t</var>.
  167. </p>
  168. </dd>
  169. <dt><code>ODD(<var>i</var>)</code></dt>
  170. <dd><p>Returns boolean TRUE if <var>i</var> is an odd number.
  171. </p>
  172. </dd>
  173. <dt><code>ORD(<var>x</var>)</code></dt>
  174. <dd><p>Returns the ordinal value of its argument. For example, the ordinal
  175. value of a character is its <small>ASCII</small> value (on machines supporting
  176. the <small>ASCII</small> character set). The argument <var>x</var> must be of an
  177. ordered type, which include integral, character and enumerated types.
  178. </p>
  179. </dd>
  180. <dt><code>SIZE(<var>x</var>)</code></dt>
  181. <dd><p>Returns the size of its argument. The argument <var>x</var> can be a
  182. variable or a type.
  183. </p>
  184. </dd>
  185. <dt><code>TRUNC(<var>r</var>)</code></dt>
  186. <dd><p>Returns the integral part of <var>r</var>.
  187. </p>
  188. </dd>
  189. <dt><code>TSIZE(<var>x</var>)</code></dt>
  190. <dd><p>Returns the size of its argument. The argument <var>x</var> can be a
  191. variable or a type.
  192. </p>
  193. </dd>
  194. <dt><code>VAL(<var>t</var>,<var>i</var>)</code></dt>
  195. <dd><p>Returns the member of the type <var>t</var> whose ordinal value is <var>i</var>.
  196. </p></dd>
  197. </dl>
  198. <blockquote>
  199. <p><em>Warning:</em> Sets and their operations are not yet supported, so
  200. <small>GDB</small> treats the use of procedures <code>INCL</code> and <code>EXCL</code> as
  201. an error.
  202. </p></blockquote>
  203. <a name="index-Modula_002d2-constants"></a>
  204. <hr>
  205. <div class="header">
  206. <p>
  207. Next: <a href="M2-Constants.html#M2-Constants" accesskey="n" rel="next">M2 Constants</a>, Previous: <a href="M2-Operators.html#M2-Operators" accesskey="p" rel="prev">M2 Operators</a>, Up: <a href="Modula_002d2.html#Modula_002d2" accesskey="u" rel="up">Modula-2</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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