Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / abf1ce3c4ea167e16b88f4e9bf02cd161da3a6dd / . / docs / CommandLine.html
blob: 7353375019101b4a30e102e6a93bcc7f4f378e70 [file] [log] [blame]
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]5 <title>CommandLine 2.0 Library Manual</title>
Misha Brukman3c299112003-11-07 18:11:14 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]7</head>
8<body>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]9
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]10<div class="doc_title">
11 CommandLine 2.0 Library Manual
12</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]13
14<ol>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]15 <li><a href="#introduction">Introduction</a></li>
16
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]17 <li><a href="#quickstart">Quick Start Guide</a>
18 <ol>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]21 <li><a href="#onealternative">Selecting an alternative from a
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]28 <li><a href="#referenceguide">Reference Guide</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]29 <ol>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]30 <li><a href="#positional">Positional Arguments</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]31 <ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]32 <li><a href="#--">Specifying positional options with hyphens</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]33 <li><a href="#cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]41 <li><a href="#modifiers">Option Modifiers</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]42 <ul>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]47 <li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]53 <li><a href="#toplevel">Top-Level Classes and Functions</a>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]54 <ul>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]67 parser</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]68 <li><a href="#boolparser">The <tt>parser&lt;bool&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]69 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]70 <li><a href="#stringparser">The <tt>parser&lt;string&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]71 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]72 <li><a href="#intparser">The <tt>parser&lt;int&gt;</tt>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]73 specialization</a></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]74 <li><a href="#doubleparser">The <tt>parser&lt;double&gt;</tt> and
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]75 <tt>parser&lt;float&gt;</tt> specializations</a></li>
76 </ul></li>
77 </ol></li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]78 <li><a href="#extensionguide">Extension Guide</a>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]79 <ol>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]86
Chris Lattner7911ce22004-05-23 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]89</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]90
91<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]92<div class="doc_section">
Misha Brukman8becd712003-11-07 19:42:44 +0000[diff] [blame]93 <a name="introduction">Introduction</a>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]94</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]95<!-- *********************************************************************** -->
96
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]104changed</a>).</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]105
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]110
111<ol>
Chris Lattnerae853632002-07-25 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 Lattneredf351f2003-06-21 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]117performance).</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]118
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]122error prone constructs, it also leads to dramatically cleaner source code.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]123
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]126parser. This means that you don't have to write <b>any</b> boilerplate
127code.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]128
Chris Lattnerae853632002-07-25 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]132the parser. This also makes supporting <a href="#dynamicopts">dynamically
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]133loaded options</a> trivial.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]134
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]135<li>Cleaner: CommandLine supports enum and other types directly, meaning that
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]138assigned a value that is not valid for your enum type.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]139
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]140<li>Powerful: The CommandLine library supports many different types of
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]145arguments</a>. This is possible because CommandLine is...</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]146
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]149you declare it. <a href="#customparser">Custom parsers</a> are no problem.</li>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]150
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]151<li>Labor Saving: The CommandLine library cuts down on the amount of grunt work
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]154tool. Additionally, it does most of the basic correctness checking for
155you.</li>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]163href="#cl::ConsumeAfter">interpreter style options</a>.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]164
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]165</ol>
166
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]172
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]173</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]174
175<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]176<div class="doc_section">
177 <a name="quickstart">Quick Start Guide</a>
178</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]179<!-- *********************************************************************** -->
180
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]186can do.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]187
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]188<p>To start out, you need to include the CommandLine header file into your
189program:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]190
191<pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]192 #include "Support/CommandLine.h"
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]193</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]194
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]195<p>Additionally, you need to add this as the first line of your main
196program:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]197
198<pre>
199int main(int argc, char **argv) {
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]200 <a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv);
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]201 ...
202}
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]203</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]204
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]205<p>... which actually parses the arguments and fills in the variable
206declarations.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]207
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]208<p>Now that you are ready to support command line arguments, we need to tell the
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]209system which ones we want, and what type of argument they are. The CommandLine
Chris Lattneredf351f2003-06-21 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]216represented like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]217
Misha Brukmanc53aefb2004-05-12 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]222
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]223<p>This declares a global variable "<tt>OutputFilename</tt>" that is used to
Chris Lattneredf351f2003-06-21 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]228that the data type that we are parsing is a string.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]229
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]233
234<pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]235USAGE: compiler [options]
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]236
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]237OPTIONS:
238 -help - display available options (--help-hidden for more)
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]239 <b>-o &lt;filename&gt; - Specify output filename</b>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]240</pre>
241
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]242<p>Because we specified that the command line option should parse using the
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]245example:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]246
247<pre>
248 ...
249 ofstream Output(OutputFilename.c_str());
250 if (Out.good()) ...
251 ...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]252</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]253
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]257with helper functions like <a href="#cl::desc"><tt>cl::desc(...)</tt></a>, so
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]258there are no positional dependencies to remember. The available options are
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]259discussed in detail in the <a href="#referenceguide">Reference Guide</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]260
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]261<p>Continuing the example, we would like to have our compiler take an input
Chris Lattnerae853632002-07-25 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]267in option form. We use this feature like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]268
269<pre>
Chris Lattnere76d4ab2002-08-06 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]271</pre>
272
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]279Command line options default to being optional, so if we would like to require
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]282<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]283
284<pre>
Chris Lattnere76d4ab2002-08-06 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]286</pre>
287
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]290
291<pre>
Chris Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]293</pre>
294
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]301extended to:</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]302
303<pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]304USAGE: compiler [options] <b>&lt;input file&gt;</b>
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]311<p>... indicating that an input filename is expected.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]312
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]313</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]314
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]315<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]316<div class="doc_subsection">
317 <a name="bool">Boolean Arguments</a>
318</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]319
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]326of boolean type like this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]327
328<pre>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]332</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]333
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]334<p>This does what you would expect: it declares three boolean variables
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]335("<tt>Force</tt>", "<tt>Quiet</tt>", and "<tt>Quiet2</tt>") to recognize these
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]339shown in the "<tt>--help-hidden</tt>" output).</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]340
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]341<p>The CommandLine library uses a <a href="#builtinparsers">different parser</a>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]348following inputs:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]349
350<pre>
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]362library calls to parse the string value into the specified data type.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]363
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]364<p>With the declarations above, "<tt>compiler --help</tt>" emits this:</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]365
366<pre>
367USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]368
369OPTIONS:
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]370 <b>-f - Overwrite output files</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]371 -o - Override output filename
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]372 <b>-quiet - Don't print informational messages</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]373 -help - display available options (--help-hidden for more)
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]374</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]375
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]376<p>and "<tt>opt --help-hidden</tt>" prints this:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]377
378<pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]379USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]380
381OPTIONS:
382 -f - Overwrite output files
383 -o - Override output filename
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]384 <b>-q - Don't print informational messages</b>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]385 -quiet - Don't print informational messages
386 -help - display available options (--help-hidden for more)
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]387</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]388
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]389<p>This brief example has shown you how to use the '<tt><a
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]393and <a href="#list">lists</a> of options.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]394
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]395</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]396
397<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]398<div class="doc_subsection">
399 <a name="alias">Argument Aliases</a>
400</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]401
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]406
407<pre>
408...
409 if (!Quiet &amp;&amp; !Quiet2) printInformationalMessage(...);
410...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]411</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]412
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]413<p>... which is a real pain! Instead of defining two values for the same
Chris Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]415option an <b>alias</b> for the "<tt>-quiet</tt>" option, instead of providing
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]416a value itself:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]417
418<pre>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]422</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]423
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]424<p>The third line (which is the only one we modified from above) defines a
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]425"<tt>-q</tt> alias that updates the "<tt>Quiet</tt>" variable (as specified by
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]431output</tt>).</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]432
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]433<p>Now the application code can simply use:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]434
435<pre>
436...
437 if (!Quiet) printInformationalMessage(...);
438...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]439</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]440
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]444
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]445</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]446
447<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]452
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]456<tt>std::string</tt>, <tt>bool</tt> and <tt>int</tt>, but how does it handle
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]457things it doesn't know about, like enums or '<tt>int*</tt>'s?</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]458
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]459<p>The answer is that it uses a table driven generic parser (unless you specify
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]462requires you to tell it what this mapping should be.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]463
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]468
469<ol>
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]472erroneous input for us.</li>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]473
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]474<li>We would have to test 4 different variables to see which ones are set.</li>
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]477see if some level &gt;= "<tt>-O1</tt>" is enabled.</li>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]478
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]479</ol>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]480
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]484
485<pre>
486enum OptLevel {
487 g, O1, O2, O3
488};
489
Chris Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 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 Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]496 clEnumValEnd));
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]497
498...
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]499 if (OptimizationLevel &gt;= O2) doPartialRedundancyElimination(...);
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]500...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]501</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]502
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]503<p>This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
Chris Lattnerae853632002-07-25 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 Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]506terminated with the "<tt>clEnumValEnd</tt>" argument!). The CommandLine
507library enforces
Chris Lattnerae853632002-07-25 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]510command line arguments matched the enum values. With this option added, our
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]511help output now is:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]512
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]513<pre>
514USAGE: compiler [options] &lt;input file&gt;
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]515
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]516OPTIONS:
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]517 <b>Choose optimization level:
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]518 -g - No optimizations, enable debugging
519 -O1 - Enable trivial optimizations
520 -O2 - Enable default optimizations
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]521 -O3 - Enable expensive optimizations</b>
Chris Lattnerae853632002-07-25 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]527
Misha Brukman9718e962003-10-24 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 Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]532
533<pre>
534enum OptLevel {
535 Debug, O1, O2, O3
536};
537
Chris Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 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 Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]544 clEnumValEnd));
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]545
546...
547 if (OptimizationLevel == Debug) outputDebugInfo(...);
548...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]549</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]550
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]555
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]556</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]557
558<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]559<div class="doc_subsection">
560 <a name="namedalternatives">Named Alternatives</a>
561</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]562
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]572case, the code looks like this:</p>
Chris Lattner209c7f42001-07-23 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 Lattnerdc844fa2003-06-03 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]581 <a href="#cl::values">cl::values</a>(
Chris Lattnerae853632002-07-25 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 Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]585 clEnumValEnd));
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]586</pre>
587
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]588<p>This definition defines an enumerated command line variable of type "<tt>enum
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]591the "<tt>--help</tt>" option:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]592
593<pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]594USAGE: compiler [options] &lt;input file&gt;
595
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]596OPTIONS:
Chris Lattnerae853632002-07-25 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]602 <b>-debug_level - Set the debugging level:
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]603 =none - disable debug information
604 =quick - enable quick debug information
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]605 =detailed - enable detailed debug information</b>
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]610</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]611
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]612<p>Again, the only structural difference between the debug level declaration and
Chris Lattnerae853632002-07-25 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]616that you can choose the form most appropriate for your application.</p>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]617
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]618</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]619
620<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]621<div class="doc_subsection">
622 <a name="list">Parsing a list of options</a>
623</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]624
Misha Brukman9718e962003-10-24 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 Lattnerae853632002-07-25 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]634would like to perform:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]635
636<pre>
637enum Opts {
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]638 // 'inline' is a C++ keyword, so name it 'inlining'
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]639 dce, constprop, inlining, strip
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]640};
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]641</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]642
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]643<p>Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]644
645<pre>
Chris Lattnere76d4ab2002-08-06 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 Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]648 clEnumVal(dce , "<i>Dead Code Elimination</i>"),
Misha Brukman82c89b92003-05-20 21:01:22 +0000[diff] [blame]649 clEnumVal(constprop , "<i>Constant Propagation</i>"),
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]650 clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
651 clEnumVal(strip , "<i>Strip Symbols</i>"),
Chris Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]652 clEnumValEnd));
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]653</pre>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]654
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]655<p>This defines a variable that is conceptually of the type
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]656"<tt>std::vector&lt;enum Opts&gt;</tt>". Thus, you can access it with standard
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]657vector methods:</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]658
659<pre>
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]660 for (unsigned i = 0; i != OptimizationList.size(); ++i)
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]661 switch (OptimizationList[i])
662 ...
663</pre>
664
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]665<p>... to iterate through the list of options specified.</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]666
Misha Brukman9718e962003-10-24 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 Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]674
675<pre>
676...
Chris Lattnere76d4ab2002-08-06 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 Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]678...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]679</pre>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]680
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]681<p>This variable works just like a "<tt>vector&lt;string&gt;</tt>" object. As
Chris Lattnerae853632002-07-25 19:27:01 +0000[diff] [blame]682such, accessing the list is simple, just like above. In this example, we used
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]686checking we have to do.</p>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]687
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]688</div>
Chris Lattner3e5fe172002-04-13 18:35:59 +0000[diff] [blame]689
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]690<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]694
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]706that you want. For example:</p>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]714</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]715
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]716<p>Would yield the help output:</p>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]729</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]730
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]731</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]732
733
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]734<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]735<div class="doc_section">
736 <a name="referenceguide">Reference Guide</a>
737</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]738<!-- *********************************************************************** -->
739
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]740<div class="doc_text">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]741
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]748
749<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]750<div class="doc_subsection">
751 <a name="positional">Positional Arguments</a>
752</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]753
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]761Using the CommandLine library, this would be specified as:</p>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]770
771<pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]772USAGE: spiffygrep [options] <b>&lt;regular expression&gt; &lt;input file&gt;</b>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]773
774OPTIONS:
775 -help - display available options (--help-hidden for more)
776</pre>
777
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]780
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]786
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]787</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]788
789
790<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]791<div class="doc_subsubsection">
792 <a name="--">Specifying positional options with hyphens</a>
793</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]794
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]801Note that the system <tt>grep</tt> has the same problem:</p>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]812</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]813
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]814<p>The solution for this problem is the same for both your tool and the system
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]818can use it like this:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]819
820<pre>
821 $ spiffygrep -- -foo test.txt
822 ...output...
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]823</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]824
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]825</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]826
827<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]831
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]838interpreted by the command line argument.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]839
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]846shell itself. Using the CommandLine library, we would specify this as:</p>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]852</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]853
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]854<p>which automatically provides the help output:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]855
856<pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]857USAGE: spiffysh [options] <b>&lt;input script&gt; &lt;program arguments&gt;...</b>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]858
859OPTIONS:
860 -help - display available options (--help-hidden for more)
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]861 <b>-x - Enable trace output</b>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]862</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]863
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]866<tt>Script</tt> variable will be set to "<tt>test.sh</tt>", and the
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]870
Misha Brukman9718e962003-10-24 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 Lattnerbe801bf2004-05-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]876href="#cl::list">cl::list</a> option.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]877
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]878</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]879
880<!-- ======================================================================= -->
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]881<div class="doc_subsection">
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]882 <a name="storage">Internal vs External Storage</a>
883</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]884
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]890files that use them. This is called the internal storage model.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]891
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]892<p>Sometimes, however, it is nice to separate the command line option processing
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]899<tt>CommandLine.h</tt>).</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]900
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]920<span class="doc_red">#ifdef NDEBUG
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]921#define DEBUG(X)
922#else
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]923#define DEBUG(X)</span> \
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]924 do { if (DebugFlag) { X; } } while (0)
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]925<span class="doc_red">#endif</span>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]926</pre>
927
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]928<p>This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]932where to fill in with the <a href="#cl::location">cl::location</a>
933attribute:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]934
935<pre>
936bool DebugFlag; <i>// the actual value</i>
Chris Lattner589a4cc2003-08-01 21:30:37 +0000[diff] [blame]937static <a href="#cl::opt">cl::opt</a>&lt;bool, true&gt; <i>// The parser</i>
Misha Brukmanc53aefb2004-05-12 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]939 <a href="#cl::location">cl::location</a>(DebugFlag));
940</pre>
941
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]945href="#cl::location">cl::location</a> attribute, so that <tt>DebugFlag</tt> is
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]946automatically set.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]947
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]948</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]949
950<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]951<div class="doc_subsection">
952 <a name="attributes">Option Attributes</a>
953</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]954
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]964This option is specified in simple double quotes:
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]965
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]968</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]969
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]973description for the option to be shown in the <tt>--help</tt> output for the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]974program.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]975
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]976<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b></a> attribute
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]979example.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]980
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]981<li><a name="cl::init">The <b><tt>cl::init</tt></b></a> attribute specifies an
Chris Lattnere76d4ab2002-08-06 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 Gaeke9d292ff2003-08-19 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]989the right order.)</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]990
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]991<li><a name="cl::location">The <b><tt>cl::location</tt></b></a> attribute where to
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]994information.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]995
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]999
Misha Brukman9718e962003-10-24 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 Lattnerb406ead2004-07-16 00:10:54 +0000[diff] [blame]1002<b>clEnumValEnd terminated</b> list of (option, value, description) triplets
1003that
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1008<ol>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1024that does not support it.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1025
1026</ul>
1027
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1028</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1029
1030<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1031<div class="doc_subsection">
1032 <a name="modifiers">Option Modifiers</a>
1033</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1034
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1041your application well.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1042
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1043<p>These options fall into five main catagories:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1044
1045<ol>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1049<li><a href="#valrequired">Controlling whether or not a value must be
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1054
Misha Brukman9718e962003-10-24 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 Lattner32a32842003-05-22 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1059usually shouldn't have to worry about these.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1060
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1061</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1062
1063<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1067
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1074
1075<ul>
1076
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1079href="#cl::list">cl::list</a></tt> options), indicates the option is to appear
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1080in both help listings.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1081
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1085the <tt>--help-hidden</tt> output.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1086
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1090</ul>
1091
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1092</div>
1093
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1094<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1099
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1104value for this setting allows the CommandLine library to do error checking for
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1105you.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1106
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1107<p>The allowed values for this option group are:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1108
1109<ul>
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1113href="#cl::alias">cl::alias</a></tt> classes) indicates that your program will
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1114allow either zero or one occurrence of the option to be specified.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1115
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1120
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1123
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1126
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1129
1130</ul>
1131
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1135option value is initialized with the default constructor for the data type.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1136
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1140
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1141</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1142
1143<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1147
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1153string (e.g. '<tt>-o a.out</tt>').</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1154
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1155<p>The allowed values for this option group are:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1156
1157<ul>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1158
1159<li><a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b></a> modifier
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1166href="#cl::ValueRequired">cl::ValueRequired</a> modifier.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1167
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1168<li><a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b></a> modifier
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1174a.out</tt>' to work.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1175
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1181
1182</ul>
1183
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1184<p>In general, the default values for this option group work just like you would
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1188when <a href="#extensionguide">extending the library</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1189
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1190</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1191
1192<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1193<div class="doc_subsubsection">
1194 <a name="formatting">Controlling other formatting options</a>
1195</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1196
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1202
1203<ul>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1204
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1208
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1213
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1216
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1225href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier specified.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1226
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1232values.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1233
1234</ul>
1235
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1236<p>The CommandLine library does not restrict how you use the <a
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1240and they will still work as designed.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1241
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1245
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1246<p><tt>parse(string OrigInput) {</tt>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1247
Chris Lattnere76d4ab2002-08-06 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 Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1261<li><tt>if (!OrigInput.empty()) error();</tt></li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1262
1263</ol>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1264
1265<p><tt>}</tt></p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1266
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1267</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1268
1269<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1270<div class="doc_subsubsection">
1271 <a name="misc">Miscellaneous option modifiers</a>
1272</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1273
Misha Brukman9718e962003-10-24 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 Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1279
1280<ul>
1281
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1282<li><a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b></a> modifier
Chris Lattner32a32842003-05-22 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1288more values (i.e. it is a <a href="#cl::list">cl::list</a> option).</li>
1289
Chris Lattnerbe801bf2004-05-06 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 Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1300</ul>
1301
Chris Lattnerbe801bf2004-05-06 22:03:59 +0000[diff] [blame]1302<p>So far, these are the only two miscellaneous option modifiers.</p>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1303
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1304</div>
Chris Lattner32a32842003-05-22 20:36:06 +0000[diff] [blame]1305
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1306<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1307<div class="doc_subsection">
1308 <a name="toplevel">Top-Level Classes and Functions</a>
1309</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1310
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1319classes in detail.</p>
1320
1321</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1322
1323<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1328
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1334available.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1335
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1336<p>The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1339<tt>--help</tt> option is invoked.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1340
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1341</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1342
1343<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1348
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1349<div class="doc_text">
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1350
Misha Brukman9718e962003-10-24 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 Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1364<a href="#description">additional extra text</a> to emit when the
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1365<tt>--help</tt> option is invoked.</p>
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1366
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1367<p><tt>cl::ParseEnvironmentOptions</tt> will break the environment
Brian Gaekee5842852003-08-19 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1374input.</p>
1375
1376</div>
Brian Gaekee5842852003-08-19 23:11:43 +0000[diff] [blame]1377
1378<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1382
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1388though):</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1389
1390<pre>
Chris Lattnerc1ae40c2002-08-07 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1395}
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1396</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1397
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1404
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1405<p>The third template argument specifies which parser to use. The default value
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1409href="#customparser">custom parser</a>.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1410
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1411</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1412
1413<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1417
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1421line options. It too is a templated class which can take up to three
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1422arguments:</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1423
1424<pre>
Chris Lattnerc1ae40c2002-08-07 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1429}
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1430</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1431
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1437
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1438</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1439
1440<!-- _______________________________________________________________________ -->
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1444
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1449
1450<pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1451<b>namespace</b> cl {
1452 <b>class</b> alias;
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1453}
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1454</pre>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1455
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1460
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1461</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1462
1463<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1464<div class="doc_subsection">
1465 <a name="builtinparsers">Builtin parsers</a>
1466</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1467
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1475the '<tt>parser</tt>' class.</p>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1476
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1482
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1492for any data type.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1493
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1494<li><a name="boolparser">The <b><tt>parser&lt;bool&gt;</tt> specialization</b></a>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1497"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1498
Misha Brukman9718e962003-10-24 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 Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1502
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1503<li><a name="intparser">The <b><tt>parser&lt;int&gt;</tt> specialization</b></a>
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1508'<tt>0x</tt>' or '<tt>0X</tt>'.</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1509
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1510<li><a name="doubleparser">The <b><tt>parser&lt;double&gt;</tt></b></a> and
Chris Lattnere76d4ab2002-08-06 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1515</li>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1516
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1517</ul>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1518
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1519</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1520
1521<!-- *********************************************************************** -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1522<div class="doc_section">
1523 <a name="extensionguide">Extension Guide</a>
1524</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1525<!-- *********************************************************************** -->
1526
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1532the covers and illustrates how to do some simple, common, extensions.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1533
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1534</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1535
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1536<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1537<div class="doc_subsection">
1538 <a name="customparser">Writing a custom parser</a>
1539</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1540
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1546particular parsed data type, validating the input in the process.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1547
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1548<p>There are two ways to use a new parser:</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1549
1550<ol>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1551
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1552<li>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1553
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1556
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1561
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1562</li>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1563
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1583this the default for all <tt>unsigned</tt> options.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1584
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1585<p>To start out, we declare our new <tt>FileSizeParser</tt> class:</p>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1593</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1594
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1598our custom parser know what object type to pass in to the parse method (here we
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1599declare that we parse into '<tt>unsigned</tt>' variables.</p>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1600
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1635</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1636
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1637<p>This function implements a very simple parser for the kinds of strings we are
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1642parser class, we can use it like this:</p>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1648</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1649
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1650<p>Which adds this to the output of our program:</p>
Chris Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1657</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1658
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 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 Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1671</pre>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1672
Misha Brukman9718e962003-10-24 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 Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1676
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1677</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1678
1679<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1680<div class="doc_subsection">
1681 <a name="explotingexternal">Exploiting external storage</a>
1682</div>
Chris Lattnerc1ae40c2002-08-07 18:27:04 +0000[diff] [blame]1683
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1684<div class="doc_text">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1685
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1686<p>TODO: fill in this section</p>
1687
1688</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1689
1690<!-- ======================================================================= -->
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1691<div class="doc_subsection">
1692 <a name="dynamicopts">Dynamically adding command line options</a>
1693</div>
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1694
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1695<div class="doc_text">
Chris Lattnere76d4ab2002-08-06 19:36:06 +0000[diff] [blame]1696
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1697<p>TODO: fill in this section</p>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1698
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1699</div>
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1700
Chris Lattner209c7f42001-07-23 23:03:12 +0000[diff] [blame]1701<!-- *********************************************************************** -->
1702
1703<hr>
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1704<address>
1705 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
1706 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
1707 <a href="http://validator.w3.org/check/referer"><img
1708 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
1709
1710 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1711 <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
Misha Brukman3c299112003-11-07 18:11:14 +0000[diff] [blame]1712 Last modified: $Date$
Misha Brukmanc53aefb2004-05-12 18:42:35 +0000[diff] [blame]1713</address>
Misha Brukman9718e962003-10-24 19:59:21 +0000[diff] [blame]1714
1715</body>
1716</html>