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