| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- Copyright (C) 1988-2015 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." --> |
| <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>Debugging with GDB: M2 Operators</title> |
| |
| <meta name="description" content="Debugging with GDB: M2 Operators"> |
| <meta name="keywords" content="Debugging with GDB: M2 Operators"> |
| <meta name="resource-type" content="document"> |
| <meta name="distribution" content="global"> |
| <meta name="Generator" content="makeinfo"> |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| <link href="index.html#Top" rel="start" title="Top"> |
| <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> |
| <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> |
| <link href="Modula_002d2.html#Modula_002d2" rel="up" title="Modula-2"> |
| <link href="Built_002dIn-Func_002fProc.html#Built_002dIn-Func_002fProc" rel="next" title="Built-In Func/Proc"> |
| <link href="Modula_002d2.html#Modula_002d2" rel="prev" title="Modula-2"> |
| <style type="text/css"> |
| <!-- |
| a.summary-letter {text-decoration: none} |
| blockquote.smallquotation {font-size: smaller} |
| div.display {margin-left: 3.2em} |
| div.example {margin-left: 3.2em} |
| div.indentedblock {margin-left: 3.2em} |
| div.lisp {margin-left: 3.2em} |
| div.smalldisplay {margin-left: 3.2em} |
| div.smallexample {margin-left: 3.2em} |
| div.smallindentedblock {margin-left: 3.2em; font-size: smaller} |
| div.smalllisp {margin-left: 3.2em} |
| kbd {font-style:oblique} |
| pre.display {font-family: inherit} |
| pre.format {font-family: inherit} |
| pre.menu-comment {font-family: serif} |
| pre.menu-preformatted {font-family: serif} |
| pre.smalldisplay {font-family: inherit; font-size: smaller} |
| pre.smallexample {font-size: smaller} |
| pre.smallformat {font-family: inherit; font-size: smaller} |
| pre.smalllisp {font-size: smaller} |
| span.nocodebreak {white-space:nowrap} |
| span.nolinebreak {white-space:nowrap} |
| span.roman {font-family:serif; font-weight:normal} |
| span.sansserif {font-family:sans-serif; font-weight:normal} |
| ul.no-bullet {list-style: none} |
| --> |
| </style> |
| |
| |
| </head> |
| |
| <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> |
| <a name="M2-Operators"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Built_002dIn-Func_002fProc.html#Built_002dIn-Func_002fProc" accesskey="n" rel="next">Built-In Func/Proc</a>, Up: <a href="Modula_002d2.html#Modula_002d2" accesskey="u" rel="up">Modula-2</a> [<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> |
| </div> |
| <hr> |
| <a name="Operators"></a> |
| <h4 class="subsubsection">15.4.8.1 Operators</h4> |
| <a name="index-Modula_002d2-operators"></a> |
| |
| <p>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: |
| </p> |
| <ul> |
| <li> <em>Integral types</em> consist of <code>INTEGER</code>, <code>CARDINAL</code>, and |
| their subranges. |
| |
| </li><li> <em>Character types</em> consist of <code>CHAR</code> and its subranges. |
| |
| </li><li> <em>Floating-point types</em> consist of <code>REAL</code>. |
| |
| </li><li> <em>Pointer types</em> consist of anything declared as <code>POINTER TO |
| <var>type</var></code>. |
| |
| </li><li> <em>Scalar types</em> consist of all of the above. |
| |
| </li><li> <em>Set types</em> consist of <code>SET</code> and <code>BITSET</code> types. |
| |
| </li><li> <em>Boolean types</em> consist of <code>BOOLEAN</code>. |
| </li></ul> |
| |
| <p>The following operators are supported, and appear in order of |
| increasing precedence: |
| </p> |
| <dl compact="compact"> |
| <dt><code>,</code></dt> |
| <dd><p>Function argument or array index separator. |
| </p> |
| </dd> |
| <dt><code>:=</code></dt> |
| <dd><p>Assignment. The value of <var>var</var> <code>:=</code> <var>value</var> is |
| <var>value</var>. |
| </p> |
| </dd> |
| <dt><code><<span class="roman">, </span>></code></dt> |
| <dd><p>Less than, greater than on integral, floating-point, or enumerated |
| types. |
| </p> |
| </dd> |
| <dt><code><=<span class="roman">, </span>>=</code></dt> |
| <dd><p>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>. |
| </p> |
| </dd> |
| <dt><code>=<span class="roman">, </span><><span class="roman">, </span>#</code></dt> |
| <dd><p>Equality and two ways of expressing inequality, valid on scalar types. |
| Same precedence as <code><</code>. In <small>GDB</small> scripts, only <code><></code> is |
| available for inequality, since <code>#</code> conflicts with the script |
| comment character. |
| </p> |
| </dd> |
| <dt><code>IN</code></dt> |
| <dd><p>Set membership. Defined on set types and the types of their members. |
| Same precedence as <code><</code>. |
| </p> |
| </dd> |
| <dt><code>OR</code></dt> |
| <dd><p>Boolean disjunction. Defined on boolean types. |
| </p> |
| </dd> |
| <dt><code>AND<span class="roman">, </span>&</code></dt> |
| <dd><p>Boolean conjunction. Defined on boolean types. |
| </p> |
| </dd> |
| <dt><code>@</code></dt> |
| <dd><p>The <small>GDB</small> “artificial array” operator (see <a href="Expressions.html#Expressions">Expressions</a>). |
| </p> |
| </dd> |
| <dt><code>+<span class="roman">, </span>-</code></dt> |
| <dd><p>Addition and subtraction on integral and floating-point types, or union |
| and difference on set types. |
| </p> |
| </dd> |
| <dt><code>*</code></dt> |
| <dd><p>Multiplication on integral and floating-point types, or set intersection |
| on set types. |
| </p> |
| </dd> |
| <dt><code>/</code></dt> |
| <dd><p>Division on floating-point types, or symmetric set difference on set |
| types. Same precedence as <code>*</code>. |
| </p> |
| </dd> |
| <dt><code>DIV<span class="roman">, </span>MOD</code></dt> |
| <dd><p>Integer division and remainder. Defined on integral types. Same |
| precedence as <code>*</code>. |
| </p> |
| </dd> |
| <dt><code>-</code></dt> |
| <dd><p>Negative. Defined on <code>INTEGER</code> and <code>REAL</code> data. |
| </p> |
| </dd> |
| <dt><code>^</code></dt> |
| <dd><p>Pointer dereferencing. Defined on pointer types. |
| </p> |
| </dd> |
| <dt><code>NOT</code></dt> |
| <dd><p>Boolean negation. Defined on boolean types. Same precedence as |
| <code>^</code>. |
| </p> |
| </dd> |
| <dt><code>.</code></dt> |
| <dd><p><code>RECORD</code> field selector. Defined on <code>RECORD</code> data. Same |
| precedence as <code>^</code>. |
| </p> |
| </dd> |
| <dt><code>[]</code></dt> |
| <dd><p>Array indexing. Defined on <code>ARRAY</code> data. Same precedence as <code>^</code>. |
| </p> |
| </dd> |
| <dt><code>()</code></dt> |
| <dd><p>Procedure argument list. Defined on <code>PROCEDURE</code> objects. Same precedence |
| as <code>^</code>. |
| </p> |
| </dd> |
| <dt><code>::<span class="roman">, </span>.</code></dt> |
| <dd><p><small>GDB</small> and Modula-2 scope operators. |
| </p></dd> |
| </dl> |
| |
| <blockquote> |
| <p><em>Warning:</em> Set expressions and their operations are not yet supported, so <small>GDB</small> |
| 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. |
| </p></blockquote> |
| |
| |
| <hr> |
| <div class="header"> |
| <p> |
| Next: <a href="Built_002dIn-Func_002fProc.html#Built_002dIn-Func_002fProc" accesskey="n" rel="next">Built-In Func/Proc</a>, Up: <a href="Modula_002d2.html#Modula_002d2" accesskey="u" rel="up">Modula-2</a> [<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> |
| </div> |
| |
| |
| |
| </body> |
| </html> |
