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gerrit-public.fairphone.software / toolchain / llvm-project / 3f2fa8de020866880bcbd4bc510864550740dde6 / . / llvm / docs / CommandLine.html
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Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
4<head>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]6 <title>CommandLine 2.0 Library Manual</title>
Misha Brukman7120c832003-11-07 18:11:14 +0000[diff] [blame]7 <link rel="stylesheet" href="llvm.css" type="text/css">
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]8</head>
9<body>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]10
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]11<div class="doc_title">
12 CommandLine 2.0 Library Manual
13</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]14
15<ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]16 <li><a href="#introduction">Introduction</a></li>
17
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]18 <li><a href="#quickstart">Quick Start Guide</a>
19 <ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]20 <li><a href="#bool">Boolean Arguments</a></li>
21 <li><a href="#alias">Argument Aliases</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]22 <li><a href="#onealternative">Selecting an alternative from a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]23 set of possibilities</a></li>
24 <li><a href="#namedalternatives">Named alternatives</a></li>
25 <li><a href="#list">Parsing a list of options</a></li>
26 <li><a href="#description">Adding freeform text to help output</a></li>
27 </ol></li>
28
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]29 <li><a href="#referenceguide">Reference Guide</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]30 <ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]31 <li><a href="#positional">Positional Arguments</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]32 <ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]33 <li><a href="#--">Specifying positional options with hyphens</a></li>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]34 <li><a href="#getPosition">Determining absolute position with
35 getPosition</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]36 <li><a href="#cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]37 modifier</a></li>
38 </ul></li>
39
40 <li><a href="#storage">Internal vs External Storage</a></li>
41
42 <li><a href="#attributes">Option Attributes</a></li>
43
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]44 <li><a href="#modifiers">Option Modifiers</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]45 <ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]46 <li><a href="#hiding">Hiding an option from <tt>--help</tt>
47 output</a></li>
48 <li><a href="#numoccurrences">Controlling the number of occurrences
49 required and allowed</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]50 <li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]51 specified</a></li>
52 <li><a href="#formatting">Controlling other formatting options</a></li>
53 <li><a href="#misc">Miscellaneous option modifiers</a></li>
54 </ul></li>
55
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]56 <li><a href="#toplevel">Top-Level Classes and Functions</a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]57 <ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]58 <li><a href="#cl::ParseCommandLineOptions">The
59 <tt>cl::ParseCommandLineOptions</tt> function</a></li>
60 <li><a href="#cl::ParseEnvironmentOptions">The
61 <tt>cl::ParseEnvironmentOptions</tt> function</a></li>
62 <li><a href="#cl::opt">The <tt>cl::opt</tt> class</a></li>
63 <li><a href="#cl::list">The <tt>cl::list</tt> class</a></li>
64 <li><a href="#cl::alias">The <tt>cl::alias</tt> class</a></li>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]65 <li><a href="#cl::extrahelp">The <tt>cl::extrahelp</tt> class</a></li>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]66 </ul></li>
67
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]68 <li><a href="#builtinparsers">Builtin parsers</a>
69 <ul>
70 <li><a href="#genericparser">The Generic <tt>parser&lt;t&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]71 parser</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]72 <li><a href="#boolparser">The <tt>parser&lt;bool&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]73 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]74 <li><a href="#stringparser">The <tt>parser&lt;string&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]75 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]76 <li><a href="#intparser">The <tt>parser&lt;int&gt;</tt>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]77 specialization</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]78 <li><a href="#doubleparser">The <tt>parser&lt;double&gt;</tt> and
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]79 <tt>parser&lt;float&gt;</tt> specializations</a></li>
80 </ul></li>
81 </ol></li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]82 <li><a href="#extensionguide">Extension Guide</a>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]83 <ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]84 <li><a href="#customparser">Writing a custom parser</a></li>
85 <li><a href="#explotingexternal">Exploiting external storage</a></li>
86 <li><a href="#dynamicopts">Dynamically adding command line
87 options</a></li>
88 </ol></li>
89</ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]90
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]91<div class="doc_author">
92 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]93</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]94
95<!-- *********************************************************************** -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]96<div class="doc_section">
Misha Brukman403ff612003-11-07 19:42:44 +0000[diff] [blame]97 <a name="introduction">Introduction</a>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]98</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]99<!-- *********************************************************************** -->
100
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]101<div class="doc_text">
102
103<p>This document describes the CommandLine argument processing library. It will
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]104show you how to use it, and what it can do. The CommandLine library uses a
105declarative approach to specifying the command line options that your program
106takes. By default, these options declarations implicitly hold the value parsed
107for the option declared (of course this <a href="#storage">can be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]108changed</a>).</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]109
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]110<p>Although there are a <b>lot</b> of command line argument parsing libraries
111out there in many different languages, none of them fit well with what I needed.
112By looking at the features and problems of other libraries, I designed the
113CommandLine library to have the following features:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]114
115<ol>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]116<li>Speed: The CommandLine library is very quick and uses little resources. The
117parsing time of the library is directly proportional to the number of arguments
118parsed, not the the number of options recognized. Additionally, command line
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]119argument values are captured transparently into user defined global variables,
120which can be accessed like any other variable (and with the same
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]121performance).</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]122
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]123<li>Type Safe: As a user of CommandLine, you don't have to worry about
124remembering the type of arguments that you want (is it an int? a string? a
125bool? an enum?) and keep casting it around. Not only does this help prevent
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]126error prone constructs, it also leads to dramatically cleaner source code.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]127
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]128<li>No subclasses required: To use CommandLine, you instantiate variables that
129correspond to the arguments that you would like to capture, you don't subclass a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]130parser. This means that you don't have to write <b>any</b> boilerplate
131code.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]132
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]133<li>Globally accessible: Libraries can specify command line arguments that are
134automatically enabled in any tool that links to the library. This is possible
135because the application doesn't have to keep a "list" of arguments to pass to
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]136the parser. This also makes supporting <a href="#dynamicopts">dynamically
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]137loaded options</a> trivial.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]138
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]139<li>Cleaner: CommandLine supports enum and other types directly, meaning that
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]140there is less error and more security built into the library. You don't have to
141worry about whether your integral command line argument accidentally got
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]142assigned a value that is not valid for your enum type.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]143
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]144<li>Powerful: The CommandLine library supports many different types of
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]145arguments, from simple <a href="#boolparser">boolean flags</a> to <a
146href="#cl::opt">scalars arguments</a> (<a href="#stringparser">strings</a>, <a
147href="#intparser">integers</a>, <a href="#genericparser">enums</a>, <a
148href="#doubleparser">doubles</a>), to <a href="#cl::list">lists of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]149arguments</a>. This is possible because CommandLine is...</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]150
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]151<li>Extensible: It is very simple to add a new argument type to CommandLine.
152Simply specify the parser that you want to use with the command line option when
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]153you declare it. <a href="#customparser">Custom parsers</a> are no problem.</li>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]154
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]155<li>Labor Saving: The CommandLine library cuts down on the amount of grunt work
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]156that you, the user, have to do. For example, it automatically provides a
157<tt>--help</tt> option that shows the available command line options for your
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]158tool. Additionally, it does most of the basic correctness checking for
159you.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]160
161<li>Capable: The CommandLine library can handle lots of different forms of
162options often found in real programs. For example, <a
163href="#positional">positional</a> arguments, <tt>ls</tt> style <a
164href="#cl::Grouping">grouping</a> options (to allow processing '<tt>ls
165-lad</tt>' naturally), <tt>ld</tt> style <a href="#cl::Prefix">prefix</a>
166options (to parse '<tt>-lmalloc -L/usr/lib</tt>'), and <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]167href="#cl::ConsumeAfter">interpreter style options</a>.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]168
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]169</ol>
170
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]171<p>This document will hopefully let you jump in and start using CommandLine in
172your utility quickly and painlessly. Additionally it should be a simple
173reference manual to figure out how stuff works. If it is failing in some area
174(or you want an extension to the library), nag the author, <a
175href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]176
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]177</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]178
179<!-- *********************************************************************** -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]180<div class="doc_section">
181 <a name="quickstart">Quick Start Guide</a>
182</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]183<!-- *********************************************************************** -->
184
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]185<div class="doc_text">
186
187<p>This section of the manual runs through a simple CommandLine'ification of a
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]188basic compiler tool. This is intended to show you how to jump into using the
189CommandLine library in your own program, and show you some of the cool things it
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]190can do.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]191
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]192<p>To start out, you need to include the CommandLine header file into your
193program:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]194
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]195<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]196 #include "Support/CommandLine.h"
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]197</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]198
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]199<p>Additionally, you need to add this as the first line of your main
200program:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]201
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]202<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]203int main(int argc, char **argv) {
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]204 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv);
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]205 ...
206}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]207</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]208
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]209<p>... which actually parses the arguments and fills in the variable
210declarations.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]211
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]212<p>Now that you are ready to support command line arguments, we need to tell the
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]213system which ones we want, and what type of argument they are. The CommandLine
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]214library uses a declarative syntax to model command line arguments with the
215global variable declarations that capture the parsed values. This means that
216for every command line option that you would like to support, there should be a
217global variable declaration to capture the result. For example, in a compiler,
218we would like to support the unix standard '<tt>-o &lt;filename&gt;</tt>' option
219to specify where to put the output. With the CommandLine library, this is
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]220represented like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]221
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]222<a name="value_desc_example"></a>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]223<div class="doc_code"><pre>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]224<a href="#cl::opt">cl::opt</a>&lt;string&gt; OutputFilename("<i>o</i>", <a href="#cl::desc">cl::desc</a>("<i>Specify output filename</i>"), <a href="#cl::value_desc">cl::value_desc</a>("<i>filename</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]225</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]226
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]227<p>This declares a global variable "<tt>OutputFilename</tt>" that is used to
Chris Lattner364e6312003-06-21 21:45:56 +0000[diff] [blame]228capture the result of the "<tt>o</tt>" argument (first parameter). We specify
229that this is a simple scalar option by using the "<tt><a
230href="#cl::opt">cl::opt</a></tt>" template (as opposed to the <a
231href="#list">"<tt>cl::list</tt> template</a>), and tell the CommandLine library
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]232that the data type that we are parsing is a string.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]233
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]234<p>The second and third parameters (which are optional) are used to specify what
235to output for the "<tt>--help</tt>" option. In this case, we get a line that
236looks like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]237
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]238<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]239USAGE: compiler [options]
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]240
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]241OPTIONS:
242 -help - display available options (--help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]243 <b>-o &lt;filename&gt; - Specify output filename</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]244</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]245
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]246<p>Because we specified that the command line option should parse using the
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]247<tt>string</tt> data type, the variable declared is automatically usable as a
248real string in all contexts that a normal C++ string object may be used. For
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]249example:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]250
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]251<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]252 ...
253 ofstream Output(OutputFilename.c_str());
254 if (Out.good()) ...
255 ...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]256</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]257
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]258<p>There are many different options that you can use to customize the command
259line option handling library, but the above example shows the general interface
260to these options. The options can be specified in any order, and are specified
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]261with helper functions like <a href="#cl::desc"><tt>cl::desc(...)</tt></a>, so
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]262there are no positional dependencies to remember. The available options are
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]263discussed in detail in the <a href="#referenceguide">Reference Guide</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]264
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]265<p>Continuing the example, we would like to have our compiler take an input
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]266filename as well as an output filename, but we do not want the input filename to
267be specified with a hyphen (ie, not <tt>-filename.c</tt>). To support this
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]268style of argument, the CommandLine library allows for <a
269href="#positional">positional</a> arguments to be specified for the program.
270These positional arguments are filled with command line parameters that are not
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]271in option form. We use this feature like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]272
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]273<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]274<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]275</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]276
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]277<p>This declaration indicates that the first positional argument should be
278treated as the input filename. Here we use the <tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]279href="#cl::init">cl::init</a></tt> option to specify an initial value for the
280command line option, which is used if the option is not specified (if you do not
281specify a <tt><a href="#cl::init">cl::init</a></tt> modifier for an option, then
282the default constructor for the data type is used to initialize the value).
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]283Command line options default to being optional, so if we would like to require
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]284that the user always specify an input filename, we would add the <tt><a
285href="#cl::Required">cl::Required</a></tt> flag, and we could eliminate the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]286<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]287
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]288<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]289<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <b><a href="#cl::Required">cl::Required</a></b>);
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]290</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]291
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]292<p>Again, the CommandLine library does not require the options to be specified
293in any particular order, so the above declaration is equivalent to:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]294
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]295<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]296<a href="#cl::opt">cl::opt</a>&lt;string&gt; InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::Required">cl::Required</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]297</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]298
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]299<p>By simply adding the <tt><a href="#cl::Required">cl::Required</a></tt> flag,
300the CommandLine library will automatically issue an error if the argument is not
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]301specified, which shifts all of the command line option verification code out of
302your application into the library. This is just one example of how using flags
303can alter the default behaviour of the library, on a per-option basis. By
304adding one of the declarations above, the <tt>--help</tt> option synopsis is now
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]305extended to:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]306
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]307<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]308USAGE: compiler [options] <b>&lt;input file&gt;</b>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]309
310OPTIONS:
311 -help - display available options (--help-hidden for more)
312 -o &lt;filename&gt; - Specify output filename
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]313</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]314
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]315<p>... indicating that an input filename is expected.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]316
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]317</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]318
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]319<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]320<div class="doc_subsection">
321 <a name="bool">Boolean Arguments</a>
322</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]323
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]324<div class="doc_text">
325
326<p>In addition to input and output filenames, we would like the compiler example
327to support three boolean flags: "<tt>-f</tt>" to force overwriting of the output
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]328file, "<tt>--quiet</tt>" to enable quiet mode, and "<tt>-q</tt>" for backwards
329compatibility with some of our users. We can support these by declaring options
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]330of boolean type like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]331
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]332<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]333<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
334<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
335<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet2("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"), <a href="#cl::Hidden">cl::Hidden</a>);
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]336</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]337
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]338<p>This does what you would expect: it declares three boolean variables
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]339("<tt>Force</tt>", "<tt>Quiet</tt>", and "<tt>Quiet2</tt>") to recognize these
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]340options. Note that the "<tt>-q</tt>" option is specified with the "<a
341href="#cl::Hidden"><tt>cl::Hidden</tt></a>" flag. This modifier prevents it
342from being shown by the standard "<tt>--help</tt>" output (note that it is still
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]343shown in the "<tt>--help-hidden</tt>" output).</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]344
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]345<p>The CommandLine library uses a <a href="#builtinparsers">different parser</a>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]346for different data types. For example, in the string case, the argument passed
347to the option is copied literally into the content of the string variable... we
348obviously cannot do that in the boolean case, however, so we must use a smarter
349parser. In the case of the boolean parser, it allows no options (in which case
350it assigns the value of true to the variable), or it allows the values
351"<tt>true</tt>" or "<tt>false</tt>" to be specified, allowing any of the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]352following inputs:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]353
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]354<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]355 compiler -f # No value, 'Force' == true
356 compiler -f=true # Value specified, 'Force' == true
357 compiler -f=TRUE # Value specified, 'Force' == true
358 compiler -f=FALSE # Value specified, 'Force' == false
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]359</pre></div>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]360
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]361<p>... you get the idea. The <a href="#boolparser">bool parser</a> just turns
362the string values into boolean values, and rejects things like '<tt>compiler
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]363-f=foo</tt>'. Similarly, the <a href="#doubleparser">float</a>, <a
364href="#doubleparser">double</a>, and <a href="#intparser">int</a> parsers work
365like you would expect, using the '<tt>strtol</tt>' and '<tt>strtod</tt>' C
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]366library calls to parse the string value into the specified data type.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]367
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]368<p>With the declarations above, "<tt>compiler --help</tt>" emits this:</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]369
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]370<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]371USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]372
373OPTIONS:
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]374 <b>-f - Overwrite output files</b>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]375 -o - Override output filename
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]376 <b>-quiet - Don't print informational messages</b>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]377 -help - display available options (--help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]378</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]379
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]380<p>and "<tt>opt --help-hidden</tt>" prints this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]381
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]382<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]383USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]384
385OPTIONS:
386 -f - Overwrite output files
387 -o - Override output filename
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]388 <b>-q - Don't print informational messages</b>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]389 -quiet - Don't print informational messages
390 -help - display available options (--help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]391</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]392
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]393<p>This brief example has shown you how to use the '<tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]394href="#cl::opt">cl::opt</a></tt>' class to parse simple scalar command line
395arguments. In addition to simple scalar arguments, the CommandLine library also
396provides primitives to support CommandLine option <a href="#alias">aliases</a>,
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]397and <a href="#list">lists</a> of options.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]398
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]399</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]400
401<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]402<div class="doc_subsection">
403 <a name="alias">Argument Aliases</a>
404</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]405
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]406<div class="doc_text">
407
408<p>So far, the example works well, except for the fact that we need to check the
409quiet condition like this now:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]410
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]411<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]412...
413 if (!Quiet &amp;&amp; !Quiet2) printInformationalMessage(...);
414...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]415</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]416
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]417<p>... which is a real pain! Instead of defining two values for the same
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]418condition, we can use the "<tt><a href="#cl::alias">cl::alias</a></tt>" class to make the "<tt>-q</tt>"
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]419option an <b>alias</b> for the "<tt>-quiet</tt>" option, instead of providing
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]420a value itself:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]421
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]422<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]423<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
424<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
425<a href="#cl::alias">cl::alias</a> QuietA("<i>q</i>", <a href="#cl::desc">cl::desc</a>("<i>Alias for -quiet</i>"), <a href="#cl::aliasopt">cl::aliasopt</a>(Quiet));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]426</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]427
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]428<p>The third line (which is the only one we modified from above) defines a
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]429"<tt>-q</tt> alias that updates the "<tt>Quiet</tt>" variable (as specified by
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]430the <tt><a href="#cl::aliasopt">cl::aliasopt</a></tt> modifier) whenever it is
431specified. Because aliases do not hold state, the only thing the program has to
432query is the <tt>Quiet</tt> variable now. Another nice feature of aliases is
433that they automatically hide themselves from the <tt>-help</tt> output
434(although, again, they are still visible in the <tt>--help-hidden
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]435output</tt>).</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]436
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]437<p>Now the application code can simply use:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]438
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]439<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]440...
441 if (!Quiet) printInformationalMessage(...);
442...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]443</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]444
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]445<p>... which is much nicer! The "<tt><a href="#cl::alias">cl::alias</a></tt>"
446can be used to specify an alternative name for any variable type, and has many
447uses.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]448
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]449</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]450
451<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]452<div class="doc_subsection">
453 <a name="onealternative">Selecting an alternative from a set of
454 possibilities</a>
455</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]456
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]457<div class="doc_text">
458
459<p>So far, we have seen how the CommandLine library handles builtin types like
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]460<tt>std::string</tt>, <tt>bool</tt> and <tt>int</tt>, but how does it handle
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]461things it doesn't know about, like enums or '<tt>int*</tt>'s?</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]462
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]463<p>The answer is that it uses a table driven generic parser (unless you specify
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]464your own parser, as described in the <a href="#extensionguide">Extension
Reid Spencera39bf3d2004-08-10 16:38:18 +0000[diff] [blame]465Guide</a>). This parser maps literal strings to whatever type is required, and
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]466requires you to tell it what this mapping should be.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]467
Reid Spencera39bf3d2004-08-10 16:38:18 +0000[diff] [blame]468<p>Lets say that we would like to add four optimization levels to our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]469optimizer, using the standard flags "<tt>-g</tt>", "<tt>-O0</tt>",
470"<tt>-O1</tt>", and "<tt>-O2</tt>". We could easily implement this with boolean
471options like above, but there are several problems with this strategy:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]472
473<ol>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]474<li>A user could specify more than one of the options at a time, for example,
475"<tt>opt -O3 -O2</tt>". The CommandLine library would not be able to catch this
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]476erroneous input for us.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]477
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]478<li>We would have to test 4 different variables to see which ones are set.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]479
480<li>This doesn't map to the numeric levels that we want... so we cannot easily
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]481see if some level &gt;= "<tt>-O1</tt>" is enabled.</li>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]482
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]483</ol>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]484
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]485<p>To cope with these problems, we can use an enum value, and have the
486CommandLine library fill it in with the appropriate level directly, which is
487used like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]488
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]489<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]490enum OptLevel {
491 g, O1, O2, O3
492};
493
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]494<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
495 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]496 clEnumVal(g , "<i>No optimizations, enable debugging</i>"),
497 clEnumVal(O1, "<i>Enable trivial optimizations</i>"),
498 clEnumVal(O2, "<i>Enable default optimizations</i>"),
499 clEnumVal(O3, "<i>Enable expensive optimizations</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]500 clEnumValEnd));
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]501
502...
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]503 if (OptimizationLevel &gt;= O2) doPartialRedundancyElimination(...);
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]504...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]505</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]506
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]507<p>This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]508"<tt>OptLevel</tt>" enum type. This variable can be assigned any of the values
509that are listed in the declaration (Note that the declaration list must be
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]510terminated with the "<tt>clEnumValEnd</tt>" argument!). The CommandLine
511library enforces
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]512that the user can only specify one of the options, and it ensure that only valid
513enum values can be specified. The "<tt>clEnumVal</tt>" macros ensure that the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]514command line arguments matched the enum values. With this option added, our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]515help output now is:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]516
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]517<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]518USAGE: compiler [options] &lt;input file&gt;
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]519
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]520OPTIONS:
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]521 <b>Choose optimization level:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]522 -g - No optimizations, enable debugging
523 -O1 - Enable trivial optimizations
524 -O2 - Enable default optimizations
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]525 -O3 - Enable expensive optimizations</b>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]526 -f - Overwrite output files
527 -help - display available options (--help-hidden for more)
528 -o &lt;filename&gt; - Specify output filename
529 -quiet - Don't print informational messages
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]530</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]531
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]532<p>In this case, it is sort of awkward that flag names correspond directly to
533enum names, because we probably don't want a enum definition named "<tt>g</tt>"
534in our program. Because of this, we can alternatively write this example like
535this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]536
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]537<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]538enum OptLevel {
539 Debug, O1, O2, O3
540};
541
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]542<a href="#cl::opt">cl::opt</a>&lt;OptLevel&gt; OptimizationLevel(<a href="#cl::desc">cl::desc</a>("<i>Choose optimization level:</i>"),
543 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]544 clEnumValN(Debug, "g", "<i>No optimizations, enable debugging</i>"),
545 clEnumVal(O1 , "<i>Enable trivial optimizations</i>"),
546 clEnumVal(O2 , "<i>Enable default optimizations</i>"),
547 clEnumVal(O3 , "<i>Enable expensive optimizations</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]548 clEnumValEnd));
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]549
550...
551 if (OptimizationLevel == Debug) outputDebugInfo(...);
552...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]553</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]554
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]555<p>By using the "<tt>clEnumValN</tt>" macro instead of "<tt>clEnumVal</tt>", we
556can directly specify the name that the flag should get. In general a direct
557mapping is nice, but sometimes you can't or don't want to preserve the mapping,
558which is when you would use it.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]559
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]560</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]561
562<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]563<div class="doc_subsection">
564 <a name="namedalternatives">Named Alternatives</a>
565</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]566
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]567<div class="doc_text">
568
569<p>Another useful argument form is a named alternative style. We shall use this
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]570style in our compiler to specify different debug levels that can be used.
571Instead of each debug level being its own switch, we want to support the
572following options, of which only one can be specified at a time:
573"<tt>--debug-level=none</tt>", "<tt>--debug-level=quick</tt>",
574"<tt>--debug-level=detailed</tt>". To do this, we use the exact same format as
575our optimization level flags, but we also specify an option name. For this
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]576case, the code looks like this:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]577
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]578<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]579enum DebugLev {
580 nodebuginfo, quick, detailed
581};
582
583// Enable Debug Options to be specified on the command line
Chris Lattner3b8f3da2003-06-03 04:40:06 +0000[diff] [blame]584<a href="#cl::opt">cl::opt</a>&lt;DebugLev&gt; DebugLevel("<i>debug_level</i>", <a href="#cl::desc">cl::desc</a>("<i>Set the debugging level:</i>"),
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]585 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]586 clEnumValN(nodebuginfo, "none", "<i>disable debug information</i>"),
587 clEnumVal(quick, "<i>enable quick debug information</i>"),
588 clEnumVal(detailed, "<i>enable detailed debug information</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]589 clEnumValEnd));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]590</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]591
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]592<p>This definition defines an enumerated command line variable of type "<tt>enum
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]593DebugLev</tt>", which works exactly the same way as before. The difference here
594is just the interface exposed to the user of your program and the help output by
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]595the "<tt>--help</tt>" option:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]596
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]597<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]598USAGE: compiler [options] &lt;input file&gt;
599
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]600OPTIONS:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]601 Choose optimization level:
602 -g - No optimizations, enable debugging
603 -O1 - Enable trivial optimizations
604 -O2 - Enable default optimizations
605 -O3 - Enable expensive optimizations
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]606 <b>-debug_level - Set the debugging level:
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]607 =none - disable debug information
608 =quick - enable quick debug information
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]609 =detailed - enable detailed debug information</b>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]610 -f - Overwrite output files
611 -help - display available options (--help-hidden for more)
612 -o &lt;filename&gt; - Specify output filename
613 -quiet - Don't print informational messages
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]614</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]615
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]616<p>Again, the only structural difference between the debug level declaration and
John Criswella9f34ca2004-11-21 14:34:34 +0000[diff] [blame]617the optimization level declaration is that the debug level declaration includes
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]618an option name (<tt>"debug_level"</tt>), which automatically changes how the
619library processes the argument. The CommandLine library supports both forms so
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]620that you can choose the form most appropriate for your application.</p>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]621
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]622</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]623
624<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]625<div class="doc_subsection">
626 <a name="list">Parsing a list of options</a>
627</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]628
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]629<div class="doc_text">
630
631<p>Now that we have the standard run of the mill argument types out of the way,
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]632lets get a little wild and crazy. Lets say that we want our optimizer to accept
633a <b>list</b> of optimizations to perform, allowing duplicates. For example, we
634might want to run: "<tt>compiler -dce -constprop -inline -dce -strip</tt>". In
635this case, the order of the arguments and the number of appearances is very
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]636important. This is what the "<tt><a href="#cl::list">cl::list</a></tt>"
637template is for. First, start by defining an enum of the optimizations that you
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]638would like to perform:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]639
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]640<div class="doc_code"><pre>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]641enum Opts {
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]642 // 'inline' is a C++ keyword, so name it 'inlining'
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]643 dce, constprop, inlining, strip
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]644};
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]645</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]646
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]647<p>Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]648
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]649<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]650<a href="#cl::list">cl::list</a>&lt;Opts&gt; OptimizationList(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
651 <a href="#cl::values">cl::values</a>(
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]652 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
Misha Brukman373086d2003-05-20 21:01:22 +0000[diff] [blame]653 clEnumVal(constprop , "<i>Constant Propagation</i>"),
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]654 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
655 clEnumVal(strip , "<i>Strip Symbols</i>"),
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]656 clEnumValEnd));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]657</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]658
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]659<p>This defines a variable that is conceptually of the type
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]660"<tt>std::vector&lt;enum Opts&gt;</tt>". Thus, you can access it with standard
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]661vector methods:</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]662
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]663<div class="doc_code"><pre>
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]664 for (unsigned i = 0; i != OptimizationList.size(); ++i)
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]665 switch (OptimizationList[i])
666 ...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]667</pre></div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]668
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]669<p>... to iterate through the list of options specified.</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]670
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]671<p>Note that the "<tt><a href="#cl::list">cl::list</a></tt>" template is
672completely general and may be used with any data types or other arguments that
673you can use with the "<tt><a href="#cl::opt">cl::opt</a></tt>" template. One
674especially useful way to use a list is to capture all of the positional
675arguments together if there may be more than one specified. In the case of a
676linker, for example, the linker takes several '<tt>.o</tt>' files, and needs to
677capture them into a list. This is naturally specified as:</p>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]678
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]679<div class="doc_code"><pre>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]680...
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]681<a href="#cl::list">cl::list</a>&lt;std::string&gt; InputFilenames(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("&lt;Input files&gt;"), <a href="#cl::OneOrMore">cl::OneOrMore</a>);
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]682...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]683</pre></div>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]684
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]685<p>This variable works just like a "<tt>vector&lt;string&gt;</tt>" object. As
Chris Lattner2e19f3e2002-07-25 19:27:01 +0000[diff] [blame]686such, accessing the list is simple, just like above. In this example, we used
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]687the <tt><a href="#cl::OneOrMore">cl::OneOrMore</a></tt> modifier to inform the
688CommandLine library that it is an error if the user does not specify any
689<tt>.o</tt> files on our command line. Again, this just reduces the amount of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]690checking we have to do.</p>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]691
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]692</div>
Chris Lattner03133252002-04-13 18:35:59 +0000[diff] [blame]693
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]694<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]695<div class="doc_subsection">
696 <a name="description">Adding freeform text to help output</a>
697</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]698
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]699<div class="doc_text">
700
701<p>As our program grows and becomes more mature, we may decide to put summary
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]702information about what it does into the help output. The help output is styled
703to look similar to a Unix <tt>man</tt> page, providing concise information about
704a program. Unix <tt>man</tt> pages, however often have a description about what
705the program does. To add this to your CommandLine program, simply pass a third
706argument to the <a
707href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
708call in main. This additional argument is then printed as the overview
709information for your program, allowing you to include any additional information
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]710that you want. For example:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]711
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]712<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]713int main(int argc, char **argv) {
714 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv, " CommandLine compiler example\n\n"
715 " This program blah blah blah...\n");
716 ...
717}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]718</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]719
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]720<p>would yield the help output:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]721
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]722<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]723<b>OVERVIEW: CommandLine compiler example
724
725 This program blah blah blah...</b>
726
727USAGE: compiler [options] &lt;input file&gt;
728
729OPTIONS:
730 ...
731 -help - display available options (--help-hidden for more)
732 -o &lt;filename&gt; - Specify output filename
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]733</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]734
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]735</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]736
737
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]738<!-- *********************************************************************** -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]739<div class="doc_section">
740 <a name="referenceguide">Reference Guide</a>
741</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]742<!-- *********************************************************************** -->
743
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]744<div class="doc_text">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]745
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]746<p>Now that you know the basics of how to use the CommandLine library, this
747section will give you the detailed information you need to tune how command line
748options work, as well as information on more "advanced" command line option
749processing capabilities.</p>
750
751</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]752
753<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]754<div class="doc_subsection">
755 <a name="positional">Positional Arguments</a>
756</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]757
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]758<div class="doc_text">
759
760<p>Positional arguments are those arguments that are not named, and are not
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]761specified with a hyphen. Positional arguments should be used when an option is
762specified by its position alone. For example, the standard Unix <tt>grep</tt>
763tool takes a regular expression argument, and an optional filename to search
764through (which defaults to standard input if a filename is not specified).
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]765Using the CommandLine library, this would be specified as:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]766
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]767<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]768<a href="#cl::opt">cl::opt</a>&lt;string&gt; Regex (<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;regular expression&gt;</i>"), <a href="#cl::Required">cl::Required</a>);
769<a href="#cl::opt">cl::opt</a>&lt;string&gt; Filename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input file&gt;</i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]770</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]771
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]772<p>Given these two option declarations, the <tt>--help</tt> output for our grep
773replacement would look like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]774
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]775<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]776USAGE: spiffygrep [options] <b>&lt;regular expression&gt; &lt;input file&gt;</b>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]777
778OPTIONS:
779 -help - display available options (--help-hidden for more)
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]780</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]781
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]782<p>... and the resultant program could be used just like the standard
783<tt>grep</tt> tool.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]784
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]785<p>Positional arguments are sorted by their order of construction. This means
786that command line options will be ordered according to how they are listed in a
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]787.cpp file, but will not have an ordering defined if the positional arguments
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]788are defined in multiple .cpp files. The fix for this problem is simply to
789define all of your positional arguments in one .cpp file.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]790
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]791</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]792
793
794<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]795<div class="doc_subsubsection">
796 <a name="--">Specifying positional options with hyphens</a>
797</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]798
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]799<div class="doc_text">
800
801<p>Sometimes you may want to specify a value to your positional argument that
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]802starts with a hyphen (for example, searching for '<tt>-foo</tt>' in a file). At
803first, you will have trouble doing this, because it will try to find an argument
804named '<tt>-foo</tt>', and will fail (and single quotes will not save you).
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]805Note that the system <tt>grep</tt> has the same problem:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]806
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]807<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]808 $ spiffygrep '-foo' test.txt
809 Unknown command line argument '-foo'. Try: spiffygrep --help'
810
811 $ grep '-foo' test.txt
812 grep: illegal option -- f
813 grep: illegal option -- o
814 grep: illegal option -- o
815 Usage: grep -hblcnsviw pattern file . . .
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]816</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]817
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]818<p>The solution for this problem is the same for both your tool and the system
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]819version: use the '<tt>--</tt>' marker. When the user specifies '<tt>--</tt>' on
820the command line, it is telling the program that all options after the
821'<tt>--</tt>' should be treated as positional arguments, not options. Thus, we
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]822can use it like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]823
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]824<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]825 $ spiffygrep -- -foo test.txt
826 ...output...
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]827</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]828
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]829</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]830
831<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]832<div class="doc_subsubsection">
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]833 <a name="getPosition">Determining absolute position with getPosition()</a>
834</div>
835<div class="doc_text">
836 <p>Sometimes an option can affect or modify the meaning of another option. For
837 example, consider <tt>gcc</tt>'s <tt>-x LANG</tt> option. This tells
838 <tt>gcc</tt> to ignore the suffix of subsequent positional arguments and force
839 the file to be interpreted as if it contained source code in language
840 <tt>LANG</tt>. In order to handle this properly , you need to know the
841 absolute position of each argument, especially those in lists, so their
842 interaction(s) can be applied correctly. This is also useful for options like
843 <tt>-llibname</tt> which is actually a positional argument that starts with
844 a dash.</p>
845 <p>So, generally, the problem is that you have two <tt>cl::list</tt> variables
846 that interact in some way. To ensure the correct interaction, you can use the
847 <tt>cl::list::getPosition(optnum)</tt> method. This method returns the
848 absolute position (as found on the command line) of the <tt>optnum</tt>
849 item in the <tt>cl::list</tt>.</p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]850 <p>The idiom for usage is like this:</p>
851
852 <div class="doc_code"><pre>
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]853 static cl::list&lt;std::string&gt; Files(cl::Positional, cl::OneOrMore);
854 static cl::listlt;std::string&gt; Libraries("l", cl::ZeroOrMore);
855
856 int main(int argc, char**argv) {
857 // ...
858 std::vector&lt;std::string&gt;::iterator fileIt = Files.begin();
859 std::vector&lt;std::string&gt;::iterator libIt = Libraries.begin();
860 unsigned libPos = 0, filePos = 0;
861 while ( 1 ) {
862 if ( libIt != Libraries.end() )
863 libPos = Libraries.getPosition( libIt - Libraries.begin() );
864 else
865 libPos = 0;
866 if ( fileIt != Files.end() )
867 filePos = Files.getPosition( fileIt - Files.begin() );
868 else
869 filePos = 0;
870
871 if ( filePos != 0 &amp;&amp; (libPos == 0 || filePos &lt; libPos) ) {
872 // Source File Is next
873 ++fileIt;
874 }
875 else if ( libPos != 0 &amp;&amp; (filePos == 0 || libPos &lt; filePos) ) {
876 // Library is next
877 ++libIt;
878 }
879 else
880 break; // we're done with the list
881 }
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]882 }</pre></div>
883
Reid Spencerc0f1b212004-08-13 20:19:14 +0000[diff] [blame]884 <p>Note that, for compatibility reasons, the <tt>cl::opt</tt> also supports an
885 <tt>unsigned getPosition()</tt> option that will provide the absolute position
886 of that option. You can apply the same approach as above with a
887 <tt>cl::opt</tt> and a <tt>cl::list</tt> option as you can with two lists.</p>
888</div>
889
890<!-- _______________________________________________________________________ -->
891<div class="doc_subsubsection">
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]892 <a name="cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt> modifier</a>
893</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]894
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]895<div class="doc_text">
896
897<p>The <tt>cl::ConsumeAfter</tt> <a href="#formatting">formatting option</a> is
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]898used to construct programs that use "interpreter style" option processing. With
899this style of option processing, all arguments specified after the last
900positional argument are treated as special interpreter arguments that are not
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]901interpreted by the command line argument.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]902
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]903<p>As a concrete example, lets say we are developing a replacement for the
904standard Unix Bourne shell (<tt>/bin/sh</tt>). To run <tt>/bin/sh</tt>, first
905you specify options to the shell itself (like <tt>-x</tt> which turns on trace
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]906output), then you specify the name of the script to run, then you specify
907arguments to the script. These arguments to the script are parsed by the bourne
908shell command line option processor, but are not interpreted as options to the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]909shell itself. Using the CommandLine library, we would specify this as:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]910
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]911<div class="doc_code"><pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]912<a href="#cl::opt">cl::opt</a>&lt;string&gt; Script(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;input script&gt;</i>"), <a href="#cl::init">cl::init</a>("-"));
913<a href="#cl::list">cl::list</a>&lt;string&gt; Argv(<a href="#cl::ConsumeAfter">cl::ConsumeAfter</a>, <a href="#cl::desc">cl::desc</a>("<i>&lt;program arguments&gt;...</i>"));
914<a href="#cl::opt">cl::opt</a>&lt;bool&gt; Trace("<i>x</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable trace output</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]915</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]916
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]917<p>which automatically provides the help output:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]918
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]919<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]920USAGE: spiffysh [options] <b>&lt;input script&gt; &lt;program arguments&gt;...</b>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]921
922OPTIONS:
923 -help - display available options (--help-hidden for more)
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]924 <b>-x - Enable trace output</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]925</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]926
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]927<p>At runtime, if we run our new shell replacement as `<tt>spiffysh -x test.sh
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]928-a -x -y bar</tt>', the <tt>Trace</tt> variable will be set to true, the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]929<tt>Script</tt> variable will be set to "<tt>test.sh</tt>", and the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]930<tt>Argv</tt> list will contain <tt>["-a", "-x", "-y", "bar"]</tt>, because they
931were specified after the last positional argument (which is the script
932name).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]933
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]934<p>There are several limitations to when <tt>cl::ConsumeAfter</tt> options can
935be specified. For example, only one <tt>cl::ConsumeAfter</tt> can be specified
936per program, there must be at least one <a href="#positional">positional
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]937argument</a> specified, there must not be any <a href="#cl::list">cl::list</a>
938positional arguments, and the <tt>cl::ConsumeAfter</tt> option should be a <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]939href="#cl::list">cl::list</a> option.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]940
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]941</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]942
943<!-- ======================================================================= -->
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]944<div class="doc_subsection">
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]945 <a name="storage">Internal vs External Storage</a>
946</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]947
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]948<div class="doc_text">
949
950<p>By default, all command line options automatically hold the value that they
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]951parse from the command line. This is very convenient in the common case,
952especially when combined with the ability to define command line options in the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]953files that use them. This is called the internal storage model.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]954
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]955<p>Sometimes, however, it is nice to separate the command line option processing
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]956code from the storage of the value parsed. For example, lets say that we have a
957'<tt>-debug</tt>' option that we would like to use to enable debug information
958across the entire body of our program. In this case, the boolean value
959controlling the debug code should be globally accessable (in a header file, for
960example) yet the command line option processing code should not be exposed to
961all of these clients (requiring lots of .cpp files to #include
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]962<tt>CommandLine.h</tt>).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]963
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]964<p>To do this, set up your .h file with your option, like this for example:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]965
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]966<div class="doc_code">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]967<pre>
968<i>// DebugFlag.h - Get access to the '-debug' command line option
969//
970
971// DebugFlag - This boolean is set to true if the '-debug' command line option
972// is specified. This should probably not be referenced directly, instead, use
973// the DEBUG macro below.
974//</i>
975extern bool DebugFlag;
976
977<i>// DEBUG macro - This macro should be used by code to emit debug information.
978// In the '-debug' option is specified on the command line, and if this is a
979// debug build, then the code specified as the option to the macro will be
980// executed. Otherwise it will not be. Example:
981//
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]982// DEBUG(std::cerr &lt;&lt; "Bitset contains: " &lt;&lt; Bitset &lt;&lt; "\n");
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]983//</i>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]984<span class="doc_hilite">#ifdef NDEBUG
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]985#define DEBUG(X)
986#else
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]987#define DEBUG(X)</span> do { if (DebugFlag) { X; } } while (0)
988<span class="doc_hilite">#endif</span>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]989</pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]990</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]991
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]992<p>This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]993<tt>DebugFlag</tt> explicitly if they want to. Now we just need to be able to
994set the <tt>DebugFlag</tt> boolean when the option is set. To do this, we pass
995an additial argument to our command line argument processor, and we specify
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]996where to fill in with the <a href="#cl::location">cl::location</a>
997attribute:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]998
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]999<div class="doc_code">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1000<pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1001bool DebugFlag; <i>// the actual value</i>
Chris Lattner76884682003-08-01 21:30:37 +0000[diff] [blame]1002static <a href="#cl::opt">cl::opt</a>&lt;bool, true&gt; <i>// The parser</i>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1003Debug("<i>debug</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable debug output</i>"), <a href="#cl::Hidden">cl::Hidden</a>, <a href="#cl::location">cl::location</a>(DebugFlag));
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1004</pre>
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1005</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1006
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1007<p>In the above example, we specify "<tt>true</tt>" as the second argument to
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1008the <tt><a href="#cl::opt">cl::opt</a></tt> template, indicating that the
1009template should not maintain a copy of the value itself. In addition to this,
1010we specify the <tt><a href="#cl::location">cl::location</a></tt> attribute, so
1011that <tt>DebugFlag</tt> is automatically set.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1012
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1013</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1014
1015<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1016<div class="doc_subsection">
1017 <a name="attributes">Option Attributes</a>
1018</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1019
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1020<div class="doc_text">
1021
1022<p>This section describes the basic attributes that you can specify on
1023options.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1024
1025<ul>
1026
1027<li>The option name attribute (which is required for all options, except <a
1028href="#positional">positional options</a>) specifies what the option name is.
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1029This option is specified in simple double quotes:
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1030
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1031<pre>
1032<a href="#cl::opt">cl::opt</a>&lt;<b>bool</b>&gt; Quiet("<i>quiet</i>");
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1033</pre>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1034
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1035</li>
1036
1037<li><a name="cl::desc">The <b><tt>cl::desc</tt></b></a> attribute specifies a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1038description for the option to be shown in the <tt>--help</tt> output for the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1039program.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1040
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1041<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b></a> attribute
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1042specifies a string that can be used to fine tune the <tt>--help</tt> output for
1043a command line option. Look <a href="#value_desc_example">here</a> for an
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1044example.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1045
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1046<li><a name="cl::init">The <b><tt>cl::init</tt></b></a> attribute specifies an
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1047inital value for a <a href="#cl::opt">scalar</a> option. If this attribute is
1048not specified then the command line option value defaults to the value created
Brian Gaeke8b89b2b2003-08-19 22:56:22 +0000[diff] [blame]1049by the default constructor for the type. <b>Warning</b>: If you specify both
1050<b><tt>cl::init</tt></b> and <b><tt>cl::location</tt></b> for an option,
1051you must specify <b><tt>cl::location</tt></b> first, so that when the
1052command-line parser sees <b><tt>cl::init</tt></b>, it knows where to put the
1053initial value. (You will get an error at runtime if you don't put them in
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1054the right order.)</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1055
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1056<li><a name="cl::location">The <b><tt>cl::location</tt></b></a> attribute where to
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1057store the value for a parsed command line option if using external storage. See
1058the section on <a href="#storage">Internal vs External Storage</a> for more
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1059information.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1060
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1061<li><a name="cl::aliasopt">The <b><tt>cl::aliasopt</tt></b></a> attribute
Misha Brukmanb139a7d2005-02-09 22:49:05 +0000[diff] [blame]1062specifies which option a <tt><a href="#cl::alias">cl::alias</a></tt> option is
1063an alias for.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1064
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1065<li><a name="cl::values">The <b><tt>cl::values</tt></b></a> attribute specifies
1066the string-to-value mapping to be used by the generic parser. It takes a
Chris Lattner1fbd76e2004-07-16 00:10:54 +0000[diff] [blame]1067<b>clEnumValEnd terminated</b> list of (option, value, description) triplets
1068that
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1069specify the option name, the value mapped to, and the description shown in the
1070<tt>--help</tt> for the tool. Because the generic parser is used most
1071frequently with enum values, two macros are often useful:
1072
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1073<ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1074
1075<li><a name="clEnumVal">The <b><tt>clEnumVal</tt></b></a> macro is used as a
1076nice simple way to specify a triplet for an enum. This macro automatically
1077makes the option name be the same as the enum name. The first option to the
1078macro is the enum, the second is the description for the command line
1079option.</li>
1080
1081<li><a name="clEnumValN">The <b><tt>clEnumValN</tt></b></a> macro is used to
1082specify macro options where the option name doesn't equal the enum name. For
1083this macro, the first argument is the enum value, the second is the flag name,
1084and the second is the description.</li>
1085
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1086</ol>
1087
1088You will get a compile time error if you try to use cl::values with a parser
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1089that does not support it.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1090
1091</ul>
1092
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1093</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1094
1095<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1096<div class="doc_subsection">
1097 <a name="modifiers">Option Modifiers</a>
1098</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1099
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1100<div class="doc_text">
1101
1102<p>Option modifiers are the flags and expressions that you pass into the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1103constructors for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
1104href="#cl::list">cl::list</a></tt>. These modifiers give you the ability to
1105tweak how options are parsed and how <tt>--help</tt> output is generated to fit
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1106your application well.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1107
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1108<p>These options fall into five main catagories:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1109
1110<ol>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1111<li><a href="#hiding">Hiding an option from <tt>--help</tt> output</a></li>
1112<li><a href="#numoccurrences">Controlling the number of occurrences
1113 required and allowed</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1114<li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1115 specified</a></li>
1116<li><a href="#formatting">Controlling other formatting options</a></li>
1117<li><a href="#misc">Miscellaneous option modifiers</a></li>
1118</ol>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1119
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1120<p>It is not possible to specify two options from the same catagory (you'll get
1121a runtime error) to a single option, except for options in the miscellaneous
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1122catagory. The CommandLine library specifies defaults for all of these settings
1123that are the most useful in practice and the most common, which mean that you
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1124usually shouldn't have to worry about these.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1125
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1126</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1127
1128<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1129<div class="doc_subsubsection">
1130 <a name="hiding">Hiding an option from <tt>--help</tt> output</a>
1131</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1132
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1133<div class="doc_text">
1134
1135<p>The <tt>cl::NotHidden</tt>, <tt>cl::Hidden</tt>, and
1136<tt>cl::ReallyHidden</tt> modifiers are used to control whether or not an option
1137appears in the <tt>--help</tt> and <tt>--help-hidden</tt> output for the
1138compiled program:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1139
1140<ul>
1141
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1142<li><a name="cl::NotHidden">The <b><tt>cl::NotHidden</tt></b></a> modifier
1143(which is the default for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1144href="#cl::list">cl::list</a></tt> options), indicates the option is to appear
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1145in both help listings.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1146
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1147<li><a name="cl::Hidden">The <b><tt>cl::Hidden</tt></b></a> modifier (which is the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1148default for <tt><a href="#cl::alias">cl::alias</a></tt> options), indicates that
1149the option should not appear in the <tt>--help</tt> output, but should appear in
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1150the <tt>--help-hidden</tt> output.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1151
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1152<li><a name="cl::ReallyHidden">The <b><tt>cl::ReallyHidden</tt></b></a> modifier,
1153indicates that the option should not appear in any help output.</li>
1154
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1155</ul>
1156
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1157</div>
1158
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1159<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1160<div class="doc_subsubsection">
1161 <a name="numoccurrences">Controlling the number of occurrences required and
1162 allowed</a>
1163</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1164
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1165<div class="doc_text">
1166
1167<p>This group of options is used to control how many time an option is allowed
1168(or required) to be specified on the command line of your program. Specifying a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1169value for this setting allows the CommandLine library to do error checking for
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1170you.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1171
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1172<p>The allowed values for this option group are:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1173
1174<ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1175
1176<li><a name="cl::Optional">The <b><tt>cl::Optional</tt></b></a> modifier (which
1177is the default for the <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1178href="#cl::alias">cl::alias</a></tt> classes) indicates that your program will
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1179allow either zero or one occurrence of the option to be specified.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1180
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1181<li><a name="cl::ZeroOrMore">The <b><tt>cl::ZeroOrMore</tt></b></a> modifier
1182(which is the default for the <tt><a href="#cl::list">cl::list</a></tt> class)
1183indicates that your program will allow the option to be specified zero or more
1184times.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1185
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1186<li><a name="cl::Required">The <b><tt>cl::Required</tt></b></a> modifier
1187indicates that the specified option must be specified exactly one time.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1188
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1189<li><a name="cl::OneOrMore">The <b><tt>cl::OneOrMore</tt></b></a> modifier
1190indicates that the option must be specified at least one time.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1191
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1192<li>The <b><tt>cl::ConsumeAfter</tt></b> modifier is described in the <a
1193href="#positional">Positional arguments section</a></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1194
1195</ul>
1196
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1197<p>If an option is not specified, then the value of the option is equal to the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1198value specified by the <tt><a href="#cl::init">cl::init</a></tt> attribute. If
1199the <tt><a href="#cl::init">cl::init</a></tt> attribute is not specified, the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1200option value is initialized with the default constructor for the data type.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1201
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1202<p>If an option is specified multiple times for an option of the <tt><a
1203href="#cl::opt">cl::opt</a></tt> class, only the last value will be
1204retained.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1205
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1206</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1207
1208<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1209<div class="doc_subsubsection">
1210 <a name="valrequired">Controlling whether or not a value must be specified</a>
1211</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1212
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1213<div class="doc_text">
1214
1215<p>This group of options is used to control whether or not the option allows a
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1216value to be present. In the case of the CommandLine library, a value is either
1217specified with an equal sign (e.g. '<tt>-index-depth=17</tt>') or as a trailing
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1218string (e.g. '<tt>-o a.out</tt>').</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1219
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1220<p>The allowed values for this option group are:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1221
1222<ul>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1223
1224<li><a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b></a> modifier
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1225(which is the default for <tt>bool</tt> typed options) specifies that it is
1226acceptable to have a value, or not. A boolean argument can be enabled just by
1227appearing on the command line, or it can have an explicit '<tt>-foo=true</tt>'.
1228If an option is specified with this mode, it is illegal for the value to be
1229provided without the equal sign. Therefore '<tt>-foo true</tt>' is illegal. To
1230get this behavior, you must use the <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1231href="#cl::ValueRequired">cl::ValueRequired</a> modifier.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1232
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1233<li><a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b></a> modifier
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1234(which is the default for all other types except for <a
1235href="#onealternative">unnamed alternatives using the generic parser</a>)
1236specifies that a value must be provided. This mode informs the command line
1237library that if an option is not provides with an equal sign, that the next
1238argument provided must be the value. This allows things like '<tt>-o
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1239a.out</tt>' to work.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1240
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1241<li><a name="cl::ValueDisallowed">The <b><tt>cl::ValueDisallowed</tt></b></a>
1242modifier (which is the default for <a href="#onealternative">unnamed
1243alternatives using the generic parser</a>) indicates that it is a runtime error
1244for the user to specify a value. This can be provided to disallow users from
1245providing options to boolean options (like '<tt>-foo=true</tt>').</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1246
1247</ul>
1248
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1249<p>In general, the default values for this option group work just like you would
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1250want them to. As mentioned above, you can specify the <a
1251href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier to a boolean
1252argument to restrict your command line parser. These options are mostly useful
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1253when <a href="#extensionguide">extending the library</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1254
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1255</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1256
1257<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1258<div class="doc_subsubsection">
1259 <a name="formatting">Controlling other formatting options</a>
1260</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1261
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1262<div class="doc_text">
1263
1264<p>The formatting option group is used to specify that the command line option
1265has special abilities and is otherwise different from other command line
1266arguments. As usual, you can only specify at most one of these arguments.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1267
1268<ul>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1269
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1270<li><a name="cl::NormalFormatting">The <b><tt>cl::NormalFormatting</tt></b></a>
1271modifier (which is the default all options) specifies that this option is
1272"normal".</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1273
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1274<li><a name="cl::Positional">The <b><tt>cl::Positional</tt></b></a> modifier
1275specifies that this is a positional argument, that does not have a command line
1276option associated with it. See the <a href="#positional">Positional
1277Arguments</a> section for more information.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1278
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1279<li>The <b><a href="#cl::ConsumeAfter"><tt>cl::ConsumeAfter</tt></a></b> modifier
1280specifies that this option is used to capture "interpreter style" arguments. See <a href="#cl::ConsumeAfter">this section for more information</a>.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1281
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1282<li><a name="cl::Prefix">The <b><tt>cl::Prefix</tt></b></a> modifier specifies
Reid Spencer80bb6932004-11-24 06:13:42 +0000[diff] [blame]1283that this option prefixes its value. With 'Prefix' options, the equal sign does
1284not separate the value from the option name specified. Instead, the value is
1285everything after the prefix, including any equal sign if present. This is useful
1286for processing odd arguments like <tt>-lmalloc</tt> and <tt>-L/usr/lib</tt> in a
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame^]1287linker tool or <tt>-DNAME=value</tt> in a compiler tool. Here, the
Reid Spencer80bb6932004-11-24 06:13:42 +0000[diff] [blame]1288'<tt>l</tt>', '<tt>D</tt>' and '<tt>L</tt>' options are normal string (or list)
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame^]1289options, that have the <b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b>
1290modifier added to allow the CommandLine library to recognize them. Note that
1291<b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b> options must not have the
1292<b><tt><a href="#cl::ValueDisallowed">cl::ValueDisallowed</a></tt></b> modifier
1293specified.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1294
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1295<li><a name="cl::Grouping">The <b><tt>cl::Grouping</tt></b></a> modifier is used
1296to implement unix style tools (like <tt>ls</tt>) that have lots of single letter
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1297arguments, but only require a single dash. For example, the '<tt>ls -labF</tt>'
1298command actually enables four different options, all of which are single
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame^]1299letters. Note that <b><tt><a href="#cl::Grouping">cl::Grouping</a></tt></b>
1300options cannot have values.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1301
1302</ul>
1303
Misha Brukman3f2fa8d2005-05-10 22:05:27 +0000[diff] [blame^]1304<p>The CommandLine library does not restrict how you use the <b><tt><a
1305href="#cl::Prefix">cl::Prefix</a></tt></b> or <b><tt><a
1306href="#cl::Grouping">cl::Grouping</a></tt></b> modifiers, but it is possible to
1307specify ambiguous argument settings. Thus, it is possible to have multiple
1308letter options that are prefix or grouping options, and they will still work as
1309designed.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1310
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1311<p>To do this, the CommandLine library uses a greedy algorithm to parse the
1312input option into (potentially multiple) prefix and grouping options. The
1313strategy basically looks like this:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1314
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1315<div class="doc_code"><tt>parse(string OrigInput) {</tt>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1316
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1317<ol>
1318<li><tt>string input = OrigInput;</tt>
1319<li><tt>if (isOption(input)) return getOption(input).parse();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Normal option</i>
1320<li><tt>while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// Remove the last letter</i>
1321<li><tt>if (input.empty()) return error();</tt>&nbsp;&nbsp;&nbsp;&nbsp;<i>// No matching option</i>
1322<li><tt>if (getOption(input).isPrefix())<br>
1323&nbsp;&nbsp;return getOption(input).parse(input);</tt>
1324<li><tt>while (!input.empty()) {&nbsp;&nbsp;&nbsp;&nbsp;<i>// Must be grouping options</i><br>
1325&nbsp;&nbsp;getOption(input).parse();<br>
1326&nbsp;&nbsp;OrigInput.erase(OrigInput.begin(), OrigInput.begin()+input.length());<br>
1327&nbsp;&nbsp;input = OrigInput;<br>
1328&nbsp;&nbsp;while (!isOption(input) &amp;&amp; !input.empty()) input.pop_back();<br>
1329}</tt>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1330<li><tt>if (!OrigInput.empty()) error();</tt></li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1331</ol>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1332
1333<p><tt>}</tt></p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1334</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1335
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1336</div>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1337
1338<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1339<div class="doc_subsubsection">
1340 <a name="misc">Miscellaneous option modifiers</a>
1341</div>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1342
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1343<div class="doc_text">
1344
1345<p>The miscellaneous option modifiers are the only flags where you can specify
1346more than one flag from the set: they are not mutually exclusive. These flags
1347specify boolean properties that modify the option.</p>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1348
1349<ul>
1350
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1351<li><a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b></a> modifier
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1352indicates that any commas specified for an option's value should be used to
1353split the value up into multiple values for the option. For example, these two
1354options are equivalent when <tt>cl::CommaSeparated</tt> is specified:
1355"<tt>-foo=a -foo=b -foo=c</tt>" and "<tt>-foo=a,b,c</tt>". This option only
1356makes sense to be used in a case where the option is allowed to accept one or
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1357more values (i.e. it is a <a href="#cl::list">cl::list</a> option).</li>
1358
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]1359<li><a name="cl::PositionalEatsArgs">The
1360<b><tt>cl::PositionalEatsArgs</tt></b></a> modifier (which only applies to
1361positional arguments, and only makes sense for lists) indicates that positional
1362argument should consume any strings after it (including strings that start with
1363a "-") up until another recognized positional argument. For example, if you
1364have two "eating" positional arguments "<tt>pos1</tt>" and "<tt>pos2</tt>" the
1365string "<tt>-pos1 -foo -bar baz -pos2 -bork</tt>" would cause the "<tt>-foo -bar
1366-baz</tt>" strings to be applied to the "<tt>-pos1</tt>" option and the
1367"<tt>-bork</tt>" string to be applied to the "<tt>-pos2</tt>" option.</li>
1368
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1369</ul>
1370
Chris Lattnerb68bd762004-05-06 22:03:59 +0000[diff] [blame]1371<p>So far, these are the only two miscellaneous option modifiers.</p>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1372
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1373</div>
Chris Lattner7333cc12003-05-22 20:36:06 +0000[diff] [blame]1374
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1375<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1376<div class="doc_subsection">
1377 <a name="toplevel">Top-Level Classes and Functions</a>
1378</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1379
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1380<div class="doc_text">
1381
1382<p>Despite all of the built-in flexibility, the CommandLine option library
1383really only consists of one function (<a
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1384href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>)
1385and three main classes: <a href="#cl::opt"><tt>cl::opt</tt></a>, <a
1386href="#cl::list"><tt>cl::list</tt></a>, and <a
1387href="#cl::alias"><tt>cl::alias</tt></a>. This section describes these three
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1388classes in detail.</p>
1389
1390</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1391
1392<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1393<div class="doc_subsubsection">
1394 <a name="cl::ParseCommandLineOptions">The <tt>cl::ParseCommandLineOptions</tt>
1395 function</a>
1396</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1397
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1398<div class="doc_text">
1399
1400<p>The <tt>cl::ParseCommandLineOptions</tt> function is designed to be called
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1401directly from <tt>main</tt>, and is used to fill in the values of all of the
1402command line option variables once <tt>argc</tt> and <tt>argv</tt> are
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1403available.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1404
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1405<p>The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1406(<tt>argc</tt> and <tt>argv</tt>), but may also take an optional third parameter
1407which holds <a href="#description">additional extra text</a> to emit when the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1408<tt>--help</tt> option is invoked.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1409
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1410</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1411
1412<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1413<div class="doc_subsubsection">
1414 <a name="cl::ParseEnvironmentOptions">The <tt>cl::ParseEnvironmentOptions</tt>
1415 function</a>
1416</div>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1417
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1418<div class="doc_text">
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1419
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1420<p>The <tt>cl::ParseEnvironmentOptions</tt> function has mostly the same effects
1421as <a
1422href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>,
1423except that it is designed to take values for options from an environment
1424variable, for those cases in which reading the command line is not convenient or
1425not desired. It fills in the values of all the command line option variables
1426just like <a
1427href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
1428does.</p>
1429
1430<p>It takes three parameters: first, the name of the program (since
1431<tt>argv</tt> may not be available, it can't just look in <tt>argv[0]</tt>),
1432second, the name of the environment variable to examine, and third, the optional
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1433<a href="#description">additional extra text</a> to emit when the
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1434<tt>--help</tt> option is invoked.</p>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1435
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1436<p><tt>cl::ParseEnvironmentOptions</tt> will break the environment
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1437variable's value up into words and then process them using
1438<a href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>.
1439<b>Note:</b> Currently <tt>cl::ParseEnvironmentOptions</tt> does not support
1440quoting, so an environment variable containing <tt>-option "foo bar"</tt> will
1441be parsed as three words, <tt>-option</tt>, <tt>"foo</tt>, and <tt>bar"</tt>,
1442which is different from what you would get from the shell with the same
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1443input.</p>
1444
1445</div>
Brian Gaekef2ea9e02003-08-19 23:11:43 +0000[diff] [blame]1446
1447<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1448<div class="doc_subsubsection">
1449 <a name="cl::opt">The <tt>cl::opt</tt> class</a>
1450</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1451
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1452<div class="doc_text">
1453
1454<p>The <tt>cl::opt</tt> class is the class used to represent scalar command line
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1455options, and is the one used most of the time. It is a templated class which
1456can take up to three arguments (all except for the first have default values
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1457though):</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1458
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1459<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1460<b>namespace</b> cl {
1461 <b>template</b> &lt;<b>class</b> DataType, <b>bool</b> ExternalStorage = <b>false</b>,
1462 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1463 <b>class</b> opt;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1464}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1465</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1466
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1467<p>The first template argument specifies what underlying data type the command
1468line argument is, and is used to select a default parser implementation. The
1469second template argument is used to specify whether the option should contain
1470the storage for the option (the default) or whether external storage should be
1471used to contain the value parsed for the option (see <a href="#storage">Internal
1472vs External Storage</a> for more information).</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1473
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1474<p>The third template argument specifies which parser to use. The default value
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1475selects an instantiation of the <tt>parser</tt> class based on the underlying
1476data type of the option. In general, this default works well for most
1477applications, so this option is only used when using a <a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1478href="#customparser">custom parser</a>.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1479
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1480</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1481
1482<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1483<div class="doc_subsubsection">
1484 <a name="cl::list">The <tt>cl::list</tt> class</a>
1485</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1486
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1487<div class="doc_text">
1488
1489<p>The <tt>cl::list</tt> class is the class used to represent a list of command
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1490line options. It too is a templated class which can take up to three
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1491arguments:</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1492
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1493<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1494<b>namespace</b> cl {
1495 <b>template</b> &lt;<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
1496 <b>class</b> ParserClass = parser&lt;DataType&gt; &gt;
1497 <b>class</b> list;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1498}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1499</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1500
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1501<p>This class works the exact same as the <a
1502href="#cl::opt"><tt>cl::opt</tt></a> class, except that the second argument is
1503the <b>type</b> of the external storage, not a boolean value. For this class,
1504the marker type '<tt>bool</tt>' is used to indicate that internal storage should
1505be used.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1506
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1507</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1508
1509<!-- _______________________________________________________________________ -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1510<div class="doc_subsubsection">
1511 <a name="cl::alias">The <tt>cl::alias</tt> class</a>
1512</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1513
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1514<div class="doc_text">
1515
1516<p>The <tt>cl::alias</tt> class is a nontemplated class that is used to form
1517aliases for other arguments.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1518
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1519<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1520<b>namespace</b> cl {
1521 <b>class</b> alias;
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1522}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1523</pre></div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1524
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1525<p>The <a href="#cl::aliasopt"><tt>cl::aliasopt</tt></a> attribute should be
1526used to specify which option this is an alias for. Alias arguments default to
1527being <a href="#cl::Hidden">Hidden</a>, and use the aliased options parser to do
1528the conversion from string to data.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1529
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1530</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1531
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1532<!-- _______________________________________________________________________ -->
1533<div class="doc_subsubsection">
1534 <a name="cl::extrahelp">The <tt>cl::extrahelp</tt> class</a>
1535</div>
1536
1537<div class="doc_text">
1538
1539<p>The <tt>cl::extrahelp</tt> class is a nontemplated class that allows extra
1540help text to be printed out for the <tt>--help</tt> option.</p>
1541
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1542<div class="doc_code"><pre>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1543<b>namespace</b> cl {
1544 <b>struct</b> extrahelp;
1545}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1546</pre></div>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1547
1548<p>To use the extrahelp, simply construct one with a <tt>const char*</tt>
1549parameter to the constructor. The text passed to the constructor will be printed
1550at the bottom of the help message, verbatim. Note that multiple
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1551<tt>cl::extrahelp</tt> <b>can</b> be used, but this practice is discouraged. If
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1552your tool needs to print additional help information, put all that help into a
1553single <tt>cl::extrahelp</tt> instance.</p>
1554<p>For example:</p>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1555<div class="doc_code"><pre>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1556 cl::extrahelp("\nADDITIONAL HELP:\n\n This is the extra help\n");
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1557</pre></div>
Reid Spencer5e554702004-11-16 06:11:52 +0000[diff] [blame]1558</div>
1559
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1560<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1561<div class="doc_subsection">
1562 <a name="builtinparsers">Builtin parsers</a>
1563</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1564
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1565<div class="doc_text">
1566
1567<p>Parsers control how the string value taken from the command line is
1568translated into a typed value, suitable for use in a C++ program. By default,
1569the CommandLine library uses an instance of <tt>parser&lt;type&gt;</tt> if the
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1570command line option specifies that it uses values of type '<tt>type</tt>'.
1571Because of this, custom option processing is specified with specializations of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1572the '<tt>parser</tt>' class.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1573
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1574<p>The CommandLine library provides the following builtin parser
1575specializations, which are sufficient for most applications. It can, however,
1576also be extended to work with new data types and new ways of interpreting the
1577same data. See the <a href="#customparser">Writing a Custom Parser</a> for more
1578details on this type of library extension.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1579
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1580<ul>
1581
1582<li><a name="genericparser">The <b>generic <tt>parser&lt;t&gt;</tt> parser</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1583can be used to map strings values to any data type, through the use of the <a
1584href="#cl::values">cl::values</a> property, which specifies the mapping
1585information. The most common use of this parser is for parsing enum values,
1586which allows you to use the CommandLine library for all of the error checking to
1587make sure that only valid enum values are specified (as opposed to accepting
1588arbitrary strings). Despite this, however, the generic parser class can be used
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1589for any data type.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1590
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1591<li><a name="boolparser">The <b><tt>parser&lt;bool&gt;</tt> specialization</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1592is used to convert boolean strings to a boolean value. Currently accepted
1593strings are "<tt>true</tt>", "<tt>TRUE</tt>", "<tt>True</tt>", "<tt>1</tt>",
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1594"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1595
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1596<li><a name="stringparser">The <b><tt>parser&lt;string&gt;</tt>
1597specialization</b></a> simply stores the parsed string into the string value
1598specified. No conversion or modification of the data is performed.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1599
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1600<li><a name="intparser">The <b><tt>parser&lt;int&gt;</tt> specialization</b></a>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1601uses the C <tt>strtol</tt> function to parse the string input. As such, it will
1602accept a decimal number (with an optional '+' or '-' prefix) which must start
1603with a non-zero digit. It accepts octal numbers, which are identified with a
1604'<tt>0</tt>' prefix digit, and hexadecimal numbers with a prefix of
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1605'<tt>0x</tt>' or '<tt>0X</tt>'.</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1606
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1607<li><a name="doubleparser">The <b><tt>parser&lt;double&gt;</tt></b></a> and
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1608<b><tt>parser&lt;float&gt;</tt> specializations</b> use the standard C
1609<tt>strtod</tt> function to convert floating point strings into floating point
1610values. As such, a broad range of string formats is supported, including
1611exponential notation (ex: <tt>1.7e15</tt>) and properly supports locales.
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1612</li>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1613
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1614</ul>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1615
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1616</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1617
1618<!-- *********************************************************************** -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1619<div class="doc_section">
1620 <a name="extensionguide">Extension Guide</a>
1621</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1622<!-- *********************************************************************** -->
1623
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1624<div class="doc_text">
1625
1626<p>Although the CommandLine library has a lot of functionality built into it
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1627already (as discussed previously), one of its true strengths lie in its
1628extensibility. This section discusses how the CommandLine library works under
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1629the covers and illustrates how to do some simple, common, extensions.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1630
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1631</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1632
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1633<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1634<div class="doc_subsection">
1635 <a name="customparser">Writing a custom parser</a>
1636</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1637
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1638<div class="doc_text">
1639
1640<p>One of the simplest and most common extensions is the use of a custom parser.
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1641As <a href="#builtinparsers">discussed previously</a>, parsers are the portion
1642of the CommandLine library that turns string input from the user into a
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1643particular parsed data type, validating the input in the process.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1644
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1645<p>There are two ways to use a new parser:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1646
1647<ol>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1648
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1649<li>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1650
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1651<p>Specialize the <a href="#genericparser"><tt>cl::parser</tt></a> template for
1652your custom data type.<p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1653
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1654<p>This approach has the advantage that users of your custom data type will
1655automatically use your custom parser whenever they define an option with a value
1656type of your data type. The disadvantage of this approach is that it doesn't
1657work if your fundemental data type is something that is already supported.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1658
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1659</li>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1660
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1661<li>
1662
1663<p>Write an independent class, using it explicitly from options that need
1664it.</p>
1665
1666<p>This approach works well in situations where you would line to parse an
1667option using special syntax for a not-very-special data-type. The drawback of
1668this approach is that users of your parser have to be aware that they are using
1669your parser, instead of the builtin ones.</p>
1670
1671</li>
1672
1673</ol>
1674
1675<p>To guide the discussion, we will discuss a custom parser that accepts file
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1676sizes, specified with an optional unit after the numeric size. For example, we
1677would like to parse "102kb", "41M", "1G" into the appropriate integer value. In
1678this case, the underlying data type we want to parse into is
1679'<tt>unsigned</tt>'. We choose approach #2 above because we don't want to make
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1680this the default for all <tt>unsigned</tt> options.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1681
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1682<p>To start out, we declare our new <tt>FileSizeParser</tt> class:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1683
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1684<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1685<b>struct</b> FileSizeParser : <b>public</b> cl::basic_parser&lt;<b>unsigned</b>&gt; {
1686 <i>// parse - Return true on error.</i>
1687 <b>bool</b> parse(cl::Option &amp;O, <b>const char</b> *ArgName, <b>const</b> std::string &amp;ArgValue,
1688 <b>unsigned</b> &amp;Val);
1689};
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1690</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1691
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1692<p>Our new class inherits from the <tt>cl::basic_parser</tt> template class to
1693fill in the default, boiler plate, code for us. We give it the data type that
1694we parse into (the last argument to the <tt>parse</tt> method so that clients of
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1695our custom parser know what object type to pass in to the parse method (here we
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1696declare that we parse into '<tt>unsigned</tt>' variables.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1697
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1698<p>For most purposes, the only method that must be implemented in a custom
1699parser is the <tt>parse</tt> method. The <tt>parse</tt> method is called
1700whenever the option is invoked, passing in the option itself, the option name,
1701the string to parse, and a reference to a return value. If the string to parse
1702is not well formed, the parser should output an error message and return true.
1703Otherwise it should return false and set '<tt>Val</tt>' to the parsed value. In
1704our example, we implement <tt>parse</tt> as:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1705
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1706<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1707<b>bool</b> FileSizeParser::parse(cl::Option &amp;O, <b>const char</b> *ArgName,
1708 <b>const</b> std::string &amp;Arg, <b>unsigned</b> &amp;Val) {
1709 <b>const char</b> *ArgStart = Arg.c_str();
1710 <b>char</b> *End;
1711
1712 <i>// Parse integer part, leaving 'End' pointing to the first non-integer char</i>
1713 Val = (unsigned)strtol(ArgStart, &amp;End, 0);
1714
1715 <b>while</b> (1) {
1716 <b>switch</b> (*End++) {
1717 <b>case</b> 0: <b>return</b> false; <i>// No error</i>
1718 <b>case</b> 'i': <i>// Ignore the 'i' in KiB if people use that</i>
1719 <b>case</b> 'b': <b>case</b> 'B': <i>// Ignore B suffix</i>
1720 <b>break</b>;
1721
1722 <b>case</b> 'g': <b>case</b> 'G': Val *= 1024*1024*1024; <b>break</b>;
1723 <b>case</b> 'm': <b>case</b> 'M': Val *= 1024*1024; <b>break</b>;
1724 <b>case</b> 'k': <b>case</b> 'K': Val *= 1024; <b>break</b>;
1725
1726 default:
1727 <i>// Print an error message if unrecognized character!</i>
1728 <b>return</b> O.error(": '" + Arg + "' value invalid for file size argument!");
1729 }
1730 }
1731}
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1732</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1733
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1734<p>This function implements a very simple parser for the kinds of strings we are
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1735interested in. Although it has some holes (it allows "<tt>123KKK</tt>" for
1736example), it is good enough for this example. Note that we use the option
1737itself to print out the error message (the <tt>error</tt> method always returns
1738true) in order to get a nice error message (shown below). Now that we have our
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1739parser class, we can use it like this:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1740
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1741<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1742<b>static</b> <a href="#cl::opt">cl::opt</a>&lt;<b>unsigned</b>, <b>false</b>, FileSizeParser&gt;
1743MFS(<i>"max-file-size"</i>, <a href="#cl::desc">cl::desc</a>(<i>"Maximum file size to accept"</i>),
1744 <a href="#cl::value_desc">cl::value_desc</a>("<i>size</i>"));
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1745</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1746
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1747<p>Which adds this to the output of our program:</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1748
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1749<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1750OPTIONS:
1751 -help - display available options (--help-hidden for more)
1752 ...
1753 <b>-max-file-size=&lt;size&gt; - Maximum file size to accept</b>
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1754</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1755
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1756<p>And we can test that our parse works correctly now (the test program just
1757prints out the max-file-size argument value):</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1758
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1759<div class="doc_code"><pre>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1760$ ./test
1761MFS: 0
1762$ ./test -max-file-size=123MB
1763MFS: 128974848
1764$ ./test -max-file-size=3G
1765MFS: 3221225472
1766$ ./test -max-file-size=dog
1767-max-file-size option: 'dog' value invalid for file size argument!
Misha Brukman922bf922005-03-11 00:00:33 +0000[diff] [blame]1768</pre></div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1769
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1770<p>It looks like it works. The error message that we get is nice and helpful,
1771and we seem to accept reasonable file sizes. This wraps up the "custom parser"
1772tutorial.</p>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1773
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1774</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1775
1776<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1777<div class="doc_subsection">
1778 <a name="explotingexternal">Exploiting external storage</a>
1779</div>
Chris Lattner74ea5a62002-08-07 18:27:04 +0000[diff] [blame]1780
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1781<div class="doc_text">
Reid Spencercf2bc3d2004-08-30 05:56:51 +0000[diff] [blame]1782 <p>Several of the LLVM libraries define static <tt>cl::opt</tt> instances that
1783 will automatically be included in any program that links with that library.
1784 This is a feature. However, sometimes it is necessary to know the value of the
1785 command line option outside of the library. In these cases the library does or
1786 should provide an external storage location that is accessible to users of the
1787 library. Examples of this include the <tt>llvm::DebugFlag</tt> exported by the
1788 <tt>lib/Support/Debug.cpp</tt> file and the <tt>llvm::TimePassesIsEnabled</tt>
1789 flag exported by the <tt>lib/VMCore/Pass.cpp</tt> file.</p>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1790
Reid Spencercf2bc3d2004-08-30 05:56:51 +0000[diff] [blame]1791<p>TODO: complete this section</p>
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1792
1793</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1794
1795<!-- ======================================================================= -->
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1796<div class="doc_subsection">
1797 <a name="dynamicopts">Dynamically adding command line options</a>
1798</div>
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1799
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1800<div class="doc_text">
Chris Lattner50761292002-08-06 19:36:06 +0000[diff] [blame]1801
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1802<p>TODO: fill in this section</p>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1803
Misha Brukmanc86e8b12003-10-24 19:59:21 +0000[diff] [blame]1804</div>
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1805
Chris Lattnerba025252001-07-23 23:03:12 +0000[diff] [blame]1806<!-- *********************************************************************** -->
1807
1808<hr>
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1809<address>
1810 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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1814
1815 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1816 <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
Misha Brukman7120c832003-11-07 18:11:14 +0000[diff] [blame]1817 Last modified: $Date$
Misha Brukman374258e2004-05-12 18:42:35 +0000[diff] [blame]1818</address>
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1821</html>