142 lines
6.3 KiB
HTML
142 lines
6.3 KiB
HTML
<html lang="en">
|
|
<head>
|
|
<title>M2 Operators - Debugging with GDB</title>
|
|
<meta http-equiv="Content-Type" content="text/html">
|
|
<meta name="description" content="Debugging with GDB">
|
|
<meta name="generator" content="makeinfo 4.13">
|
|
<link title="Top" rel="start" href="index.html#Top">
|
|
<link rel="up" href="Modula_002d2.html#Modula_002d2" title="Modula-2">
|
|
<link rel="next" href="Built_002dIn-Func_002fProc.html#Built_002dIn-Func_002fProc" title="Built-In Func/Proc">
|
|
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
|
|
<!--
|
|
Copyright (C) 1988-2019 Free Software Foundation, Inc.
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with the
|
|
Invariant Sections being ``Free Software'' and ``Free Software Needs
|
|
Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
|
|
and with the Back-Cover Texts as in (a) below.
|
|
|
|
(a) The FSF's Back-Cover Text is: ``You are free to copy and modify
|
|
this GNU Manual. Buying copies from GNU Press supports the FSF in
|
|
developing GNU and promoting software freedom.''
|
|
-->
|
|
<meta http-equiv="Content-Style-Type" content="text/css">
|
|
<style type="text/css"><!--
|
|
pre.display { font-family:inherit }
|
|
pre.format { font-family:inherit }
|
|
pre.smalldisplay { font-family:inherit; font-size:smaller }
|
|
pre.smallformat { font-family:inherit; font-size:smaller }
|
|
pre.smallexample { font-size:smaller }
|
|
pre.smalllisp { font-size:smaller }
|
|
span.sc { font-variant:small-caps }
|
|
span.roman { font-family:serif; font-weight:normal; }
|
|
span.sansserif { font-family:sans-serif; font-weight:normal; }
|
|
--></style>
|
|
</head>
|
|
<body>
|
|
<div class="node">
|
|
<a name="M2-Operators"></a>
|
|
<p>
|
|
Next: <a rel="next" accesskey="n" href="Built_002dIn-Func_002fProc.html#Built_002dIn-Func_002fProc">Built-In Func/Proc</a>,
|
|
Up: <a rel="up" accesskey="u" href="Modula_002d2.html#Modula_002d2">Modula-2</a>
|
|
<hr>
|
|
</div>
|
|
|
|
<h5 class="subsubsection">15.4.9.1 Operators</h5>
|
|
|
|
<p><a name="index-Modula_002d2-operators-1044"></a>
|
|
Operators must be defined on values of specific types. For instance,
|
|
<code>+</code> is defined on numbers, but not on structures. Operators are
|
|
often defined on groups of types. For the purposes of Modula-2, the
|
|
following definitions hold:
|
|
|
|
<ul>
|
|
<li><em>Integral types</em> consist of <code>INTEGER</code>, <code>CARDINAL</code>, and
|
|
their subranges.
|
|
|
|
<li><em>Character types</em> consist of <code>CHAR</code> and its subranges.
|
|
|
|
<li><em>Floating-point types</em> consist of <code>REAL</code>.
|
|
|
|
<li><em>Pointer types</em> consist of anything declared as <code>POINTER TO
|
|
</code><var>type</var>.
|
|
|
|
<li><em>Scalar types</em> consist of all of the above.
|
|
|
|
<li><em>Set types</em> consist of <code>SET</code> and <code>BITSET</code> types.
|
|
|
|
<li><em>Boolean types</em> consist of <code>BOOLEAN</code>.
|
|
</ul>
|
|
|
|
<p class="noindent">The following operators are supported, and appear in order of
|
|
increasing precedence:
|
|
|
|
<dl>
|
|
<dt><code>,</code><dd>Function argument or array index separator.
|
|
|
|
<br><dt><code>:=</code><dd>Assignment. The value of <var>var</var> <code>:=</code> <var>value</var> is
|
|
<var>value</var>.
|
|
|
|
<br><dt><code><</code><span class="roman">, </span><code>></code><dd>Less than, greater than on integral, floating-point, or enumerated
|
|
types.
|
|
|
|
<br><dt><code><=</code><span class="roman">, </span><code>>=</code><dd>Less than or equal to, greater than or equal to
|
|
on integral, floating-point and enumerated types, or set inclusion on
|
|
set types. Same precedence as <code><</code>.
|
|
|
|
<br><dt><code>=</code><span class="roman">, </span><code><></code><span class="roman">, </span><code>#</code><dd>Equality and two ways of expressing inequality, valid on scalar types.
|
|
Same precedence as <code><</code>. In <span class="sc">gdb</span> scripts, only <code><></code> is
|
|
available for inequality, since <code>#</code> conflicts with the script
|
|
comment character.
|
|
|
|
<br><dt><code>IN</code><dd>Set membership. Defined on set types and the types of their members.
|
|
Same precedence as <code><</code>.
|
|
|
|
<br><dt><code>OR</code><dd>Boolean disjunction. Defined on boolean types.
|
|
|
|
<br><dt><code>AND</code><span class="roman">, </span><code>&</code><dd>Boolean conjunction. Defined on boolean types.
|
|
|
|
<br><dt><code>@</code><dd>The <span class="sc">gdb</span> “artificial array” operator (see <a href="Expressions.html#Expressions">Expressions</a>).
|
|
|
|
<br><dt><code>+</code><span class="roman">, </span><code>-</code><dd>Addition and subtraction on integral and floating-point types, or union
|
|
and difference on set types.
|
|
|
|
<br><dt><code>*</code><dd>Multiplication on integral and floating-point types, or set intersection
|
|
on set types.
|
|
|
|
<br><dt><code>/</code><dd>Division on floating-point types, or symmetric set difference on set
|
|
types. Same precedence as <code>*</code>.
|
|
|
|
<br><dt><code>DIV</code><span class="roman">, </span><code>MOD</code><dd>Integer division and remainder. Defined on integral types. Same
|
|
precedence as <code>*</code>.
|
|
|
|
<br><dt><code>-</code><dd>Negative. Defined on <code>INTEGER</code> and <code>REAL</code> data.
|
|
|
|
<br><dt><code>^</code><dd>Pointer dereferencing. Defined on pointer types.
|
|
|
|
<br><dt><code>NOT</code><dd>Boolean negation. Defined on boolean types. Same precedence as
|
|
<code>^</code>.
|
|
|
|
<br><dt><code>.</code><dd><code>RECORD</code> field selector. Defined on <code>RECORD</code> data. Same
|
|
precedence as <code>^</code>.
|
|
|
|
<br><dt><code>[]</code><dd>Array indexing. Defined on <code>ARRAY</code> data. Same precedence as <code>^</code>.
|
|
|
|
<br><dt><code>()</code><dd>Procedure argument list. Defined on <code>PROCEDURE</code> objects. Same precedence
|
|
as <code>^</code>.
|
|
|
|
<br><dt><code>::</code><span class="roman">, </span><code>.</code><dd><span class="sc">gdb</span> and Modula-2 scope operators.
|
|
</dl>
|
|
|
|
<blockquote>
|
|
<em>Warning:</em> Set expressions and their operations are not yet supported, so <span class="sc">gdb</span>
|
|
treats the use of the operator <code>IN</code>, or the use of operators
|
|
<code>+</code>, <code>-</code>, <code>*</code>, <code>/</code>, <code>=</code>, , <code><></code>, <code>#</code>,
|
|
<code><=</code>, and <code>>=</code> on sets as an error.
|
|
</blockquote>
|
|
|
|
</body></html>
|
|
|