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+ <title>CommandLine 2.0 Library Manual</title>
+ <link rel="stylesheet" href="llvm.css" type="text/css">
+</head>
+<body>
+
+<div class="doc_title">
+ CommandLine 2.0 Library Manual
+</div>
<ol>
- <li><a href="#introduction">Introduction</a>
+ <li><a href="#introduction">Introduction</a></li>
+
<li><a href="#quickstart">Quick Start Guide</a>
<ol>
- <li><a href="#bool">Boolean Arguments</a>
- <li><a href="#alias">Argument Aliases</a>
+ <li><a href="#bool">Boolean Arguments</a></li>
+ <li><a href="#alias">Argument Aliases</a></li>
<li><a href="#onealternative">Selecting an alternative from a
- set of possibilities</a>
- <li><a href="#namedalternatives">Named alternatives</a>
- <li><a href="#list">Parsing a list of options</a>
- <li><a href="#description">Adding freeform text to help output</a>
- </ol>
+ set of possibilities</a></li>
+ <li><a href="#namedalternatives">Named alternatives</a></li>
+ <li><a href="#list">Parsing a list of options</a></li>
+ <li><a href="#bits">Collecting options as a set of flags</a></li>
+ <li><a href="#description">Adding freeform text to help output</a></li>
+ </ol></li>
+
<li><a href="#referenceguide">Reference Guide</a>
<ol>
<li><a href="#positional">Positional Arguments</a>
<ul>
- <li><a href="#--">Specifying positional options with hyphens</a>
+ <li><a href="#--">Specifying positional options with hyphens</a></li>
+ <li><a href="#getPosition">Determining absolute position with
+ getPosition</a></li>
<li><a href="#cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt>
- modifier</a>
- </ul>
- <li><a href="#storage">Internal vs External Storage</a>
- <li><a href="#attributes">Option Attributes</a>
+ modifier</a></li>
+ </ul></li>
+
+ <li><a href="#storage">Internal vs External Storage</a></li>
+
+ <li><a href="#attributes">Option Attributes</a></li>
+
<li><a href="#modifiers">Option Modifiers</a>
<ul>
- <li><a href="#hiding">Hiding an option from <tt>--help</tt> output</a>
- <li><a href="#numoccurances">Controlling the number of occurances
- required and allowed</a>
+ <li><a href="#hiding">Hiding an option from <tt>--help</tt>
+ output</a></li>
+ <li><a href="#numoccurrences">Controlling the number of occurrences
+ required and allowed</a></li>
<li><a href="#valrequired">Controlling whether or not a value must be
- specified</a>
- <li><a href="#formatting">Controlling other formatting options</a>
- <li><a href="#misc">Miscellaneous option modifiers</a>
- </ul>
+ specified</a></li>
+ <li><a href="#formatting">Controlling other formatting options</a></li>
+ <li><a href="#misc">Miscellaneous option modifiers</a></li>
+ </ul></li>
+
<li><a href="#toplevel">Top-Level Classes and Functions</a>
<ul>
- <li><a href="#cl::ParseCommandLineOptions">The
- <tt>cl::ParseCommandLineOptions</tt> function</a>
- <li><a href="#cl::opt">The <tt>cl::opt</tt> class</a>
- <li><a href="#cl::list">The <tt>cl::list</tt> class</a>
- <li><a href="#cl::alias">The <tt>cl::alias</tt> class</a>
- </ul>
+ <li><a href="#cl::ParseCommandLineOptions">The
+ <tt>cl::ParseCommandLineOptions</tt> function</a></li>
+ <li><a href="#cl::ParseEnvironmentOptions">The
+ <tt>cl::ParseEnvironmentOptions</tt> function</a></li>
+ <li><a href="#cl::SetVersionPrinter">The cl::SetVersionPrinter
+ function</a></li>
+ <li><a href="#cl::opt">The <tt>cl::opt</tt> class</a></li>
+ <li><a href="#cl::list">The <tt>cl::list</tt> class</a></li>
+ <li><a href="#cl::bits">The <tt>cl::bits</tt> class</a></li>
+ <li><a href="#cl::alias">The <tt>cl::alias</tt> class</a></li>
+ <li><a href="#cl::extrahelp">The <tt>cl::extrahelp</tt> class</a></li>
+ </ul></li>
+
<li><a href="#builtinparsers">Builtin parsers</a>
<ul>
<li><a href="#genericparser">The Generic <tt>parser<t></tt>
- parser</a>
+ parser</a></li>
<li><a href="#boolparser">The <tt>parser<bool></tt>
- specialization</a>
+ specialization</a></li>
+ <li><a href="#boolOrDefaultparser">The <tt>parser<boolOrDefault></tt>
+ specialization</a></li>
<li><a href="#stringparser">The <tt>parser<string></tt>
- specialization</a>
+ specialization</a></li>
<li><a href="#intparser">The <tt>parser<int></tt>
- specialization</a>
+ specialization</a></li>
<li><a href="#doubleparser">The <tt>parser<double></tt> and
- <tt>parser<float></tt> specializations</a>
- </ul>
- </ol>
+ <tt>parser<float></tt> specializations</a></li>
+ </ul></li>
+ </ol></li>
<li><a href="#extensionguide">Extension Guide</a>
<ol>
- <li><a href="#customparser">Writing a custom parser</a>
- <li><a href="#explotingexternal">Exploiting external storage</a>
- <li><a href="#dynamicopts">Dynamically adding command line options</a>
- </ol>
-
- <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
-</ol><p>
+ <li><a href="#customparser">Writing a custom parser</a></li>
+ <li><a href="#explotingexternal">Exploiting external storage</a></li>
+ <li><a href="#dynamicopts">Dynamically adding command line
+ options</a></li>
+ </ol></li>
+</ol>
+<div class="doc_author">
+ <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
+</div>
<!-- *********************************************************************** -->
-<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="introduction">Introduction
-</b></font></td></tr></table><ul>
+<div class="doc_section">
+ <a name="introduction">Introduction</a>
+</div>
<!-- *********************************************************************** -->
-This document describes the CommandLine argument processing library. It will
+<div class="doc_text">
+
+<p>This document describes the CommandLine argument processing library. It will
show you how to use it, and what it can do. The CommandLine library uses a
declarative approach to specifying the command line options that your program
takes. By default, these options declarations implicitly hold the value parsed
for the option declared (of course this <a href="#storage">can be
-changed</a>).<p>
+changed</a>).</p>
-Although there are a <b>lot</b> of command line argument parsing libraries out
-there in many different languages, none of them fit well with what I needed. By
-looking at the features and problems of other libraries, I designed the
-CommandLine library to have the following features:<p>
+<p>Although there are a <b>lot</b> of command line argument parsing libraries
+out there in many different languages, none of them fit well with what I needed.
+By looking at the features and problems of other libraries, I designed the
+CommandLine library to have the following features:</p>
<ol>
<li>Speed: The CommandLine library is very quick and uses little resources. The
parsing time of the library is directly proportional to the number of arguments
parsed, not the the number of options recognized. Additionally, command line
-argument values are captured transparently into user defined variables, which
-can be accessed like any other variable (and with the same performance).<p>
+argument values are captured transparently into user defined global variables,
+which can be accessed like any other variable (and with the same
+performance).</li>
<li>Type Safe: As a user of CommandLine, you don't have to worry about
remembering the type of arguments that you want (is it an int? a string? a
bool? an enum?) and keep casting it around. Not only does this help prevent
-error prone constructs, it also leads to dramatically cleaner source code.<p>
+error prone constructs, it also leads to dramatically cleaner source code.</li>
<li>No subclasses required: To use CommandLine, you instantiate variables that
correspond to the arguments that you would like to capture, you don't subclass a
-parser. This means that you don't have to write <b>any</b> boilerplate code.<p>
+parser. This means that you don't have to write <b>any</b> boilerplate
+code.</li>
<li>Globally accessible: Libraries can specify command line arguments that are
automatically enabled in any tool that links to the library. This is possible
because the application doesn't have to keep a "list" of arguments to pass to
the parser. This also makes supporting <a href="#dynamicopts">dynamically
-loaded options</a> trivial.<p>
+loaded options</a> trivial.</li>
<li>Cleaner: CommandLine supports enum and other types directly, meaning that
there is less error and more security built into the library. You don't have to
worry about whether your integral command line argument accidentally got
-assigned a value that is not valid for your enum type.<p>
+assigned a value that is not valid for your enum type.</li>
<li>Powerful: The CommandLine library supports many different types of
arguments, from simple <a href="#boolparser">boolean flags</a> to <a
href="#cl::opt">scalars arguments</a> (<a href="#stringparser">strings</a>, <a
href="#intparser">integers</a>, <a href="#genericparser">enums</a>, <a
href="#doubleparser">doubles</a>), to <a href="#cl::list">lists of
-arguments</a>. This is possible because CommandLine is...<p>
+arguments</a>. This is possible because CommandLine is...</li>
<li>Extensible: It is very simple to add a new argument type to CommandLine.
Simply specify the parser that you want to use with the command line option when
-you declare it. <a href="#customparser">Custom parsers</a> are no problem.<p>
+you declare it. <a href="#customparser">Custom parsers</a> are no problem.</li>
<li>Labor Saving: The CommandLine library cuts down on the amount of grunt work
that you, the user, have to do. For example, it automatically provides a
<tt>--help</tt> option that shows the available command line options for your
-tool. Additionally, it does most of the basic correctness checking for you.<p>
+tool. Additionally, it does most of the basic correctness checking for
+you.</li>
<li>Capable: The CommandLine library can handle lots of different forms of
options often found in real programs. For example, <a
href="#cl::Grouping">grouping</a> options (to allow processing '<tt>ls
-lad</tt>' naturally), <tt>ld</tt> style <a href="#cl::Prefix">prefix</a>
options (to parse '<tt>-lmalloc -L/usr/lib</tt>'), and <a
-href="#cl::ConsumeAfter">interpreter style options</a>.<p>
+href="#cl::ConsumeAfter">interpreter style options</a>.</li>
</ol>
-This document will hopefully let you jump in and start using CommandLine in your
-utility quickly and painlessly. Additionally it should be a simple reference
-manual to figure out how stuff works. If it is failing in some area (or you
-want an extension to the library), nag the author, <a
-href="mailto:sabre@nondot.org">Chris Lattner</a>.<p>
-
+<p>This document will hopefully let you jump in and start using CommandLine in
+your utility quickly and painlessly. Additionally it should be a simple
+reference manual to figure out how stuff works. If it is failing in some area
+(or you want an extension to the library), nag the author, <a
+href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="quickstart">Quick Start Guide
-</b></font></td></tr></table><ul>
+<div class="doc_section">
+ <a name="quickstart">Quick Start Guide</a>
+</div>
<!-- *********************************************************************** -->
-This section of the manual runs through a simple CommandLine'ification of a
+<div class="doc_text">
+
+<p>This section of the manual runs through a simple CommandLine'ification of a
basic compiler tool. This is intended to show you how to jump into using the
CommandLine library in your own program, and show you some of the cool things it
-can do.<p>
+can do.</p>
-To start out, you need to include the CommandLine header file into your
-program:<p>
+<p>To start out, you need to include the CommandLine header file into your
+program:</p>
-<pre>
- #include "Support/CommandLine.h"
-</pre><p>
+<div class="doc_code"><pre>
+ #include "llvm/Support/CommandLine.h"
+</pre></div>
-Additionally, you need to add this as the first line of your main program:<p>
+<p>Additionally, you need to add this as the first line of your main
+program:</p>
-<pre>
+<div class="doc_code"><pre>
int main(int argc, char **argv) {
<a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv);
...
}
-</pre><p>
+</pre></div>
-... which actually parses the arguments and fills in the variable
-declarations.<p>
+<p>... which actually parses the arguments and fills in the variable
+declarations.</p>
-Now that you are ready to support command line arguments, we need to tell the
+<p>Now that you are ready to support command line arguments, we need to tell the
system which ones we want, and what type of argument they are. The CommandLine
-library uses a declarative syntax to model cammand line arguments with the
-variable declarations that capture the parsed values. This means that for every
-command line option that you would like to support, there should be a variable
-declaration to capture the result. For example, in a compiler, we would like to
-support the unix standard '<tt>-o <filename></tt>' option to specify where
-to put the output. With the CommandLine library, this is represented like
-this:<p>
-
-<pre><a name="value_desc_example">
+library uses a declarative syntax to model command line arguments with the
+global variable declarations that capture the parsed values. This means that
+for every command line option that you would like to support, there should be a
+global variable declaration to capture the result. For example, in a compiler,
+we would like to support the unix standard '<tt>-o <filename></tt>' option
+to specify where to put the output. With the CommandLine library, this is
+represented like this:</p>
+
+<a name="value_desc_example"></a>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> 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>"));
-</pre><p>
+</pre></div>
-This declares a variable "<tt>OutputFilename</tt>" that is used to capture the
-result of the "<tt>o</tt>" argument (first parameter). We specify that this is
-a simple scalar option by using the "<tt><a href="#cl::opt">cl::opt</a></tt>"
-template (as opposed to the <a href="#list">"<tt>cl::list</tt>
-template</a>), and tell the CommandLine library that the data type that we are
-parsing is a string.<p>
+<p>This declares a global variable "<tt>OutputFilename</tt>" that is used to
+capture the result of the "<tt>o</tt>" argument (first parameter). We specify
+that this is a simple scalar option by using the "<tt><a
+href="#cl::opt">cl::opt</a></tt>" template (as opposed to the <a
+href="#list">"<tt>cl::list</tt> template</a>), and tell the CommandLine library
+that the data type that we are parsing is a string.</p>
-The second and third parameters (which are optional) are used to specify what to
-output for the "<tt>--help</tt>" option. In this case, we get a line that looks
-like this:<p>
+<p>The second and third parameters (which are optional) are used to specify what
+to output for the "<tt>--help</tt>" option. In this case, we get a line that
+looks like this:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options]
OPTIONS:
-help - display available options (--help-hidden for more)
<b>-o <filename> - Specify output filename</b>
-</pre>
+</pre></div>
-Because we specified that the command line option should parse using the
+<p>Because we specified that the command line option should parse using the
<tt>string</tt> data type, the variable declared is automatically usable as a
real string in all contexts that a normal C++ string object may be used. For
-example:<p>
+example:</p>
-<pre>
+<div class="doc_code"><pre>
...
ofstream Output(OutputFilename.c_str());
if (Out.good()) ...
...
-</pre><p>
+</pre></div>
-There are many different options that you can use to customize the command line
-option handling library, but the above example shows the general interface to
-these options. The options can be specified in any order, and are specified
+<p>There are many different options that you can use to customize the command
+line option handling library, but the above example shows the general interface
+to these options. The options can be specified in any order, and are specified
with helper functions like <a href="#cl::desc"><tt>cl::desc(...)</tt></a>, so
there are no positional dependencies to remember. The available options are
-discussed in detail in the <a href="#referenceguide">Reference Guide</a>.<p>
+discussed in detail in the <a href="#referenceguide">Reference Guide</a>.</p>
-
-Continuing the example, we would like to have our compiler take an input
+<p>Continuing the example, we would like to have our compiler take an input
filename as well as an output filename, but we do not want the input filename to
be specified with a hyphen (ie, not <tt>-filename.c</tt>). To support this
style of argument, the CommandLine library allows for <a
href="#positional">positional</a> arguments to be specified for the program.
These positional arguments are filled with command line parameters that are not
-in option form. We use this feature like this:<p>
+in option form. We use this feature like this:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i><input file></i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
-</pre>
+</pre></div>
-This declaration indicates that the first positional argument should be treated
-as the input filename. Here we use the <tt><a
+<p>This declaration indicates that the first positional argument should be
+
treated as the input filename. Here we use the <tt><a
href="#cl::init">cl::init</a></tt> option to specify an initial value for the
command line option, which is used if the option is not specified (if you do not
specify a <tt><a href="#cl::init">cl::init</a></tt> modifier for an option, then
Command line options default to being optional, so if we would like to require
that the user always specify an input filename, we would add the <tt><a
href="#cl::Required">cl::Required</a></tt> flag, and we could eliminate the
-<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:<p>
+<tt><a href="#cl::init">cl::init</a></tt> modifier, like this:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i><input file></i>"), <b><a href="#cl::Required">cl::Required</a></b>);
-</pre>
+</pre></div>
-Again, the CommandLine library does not require the options to be specified in
-any particular order, so the above declaration is equivalent to:<p>
+<p>Again, the CommandLine library does not require the options to be specified
+in any particular order, so the above declaration is equivalent to:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> InputFilename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::Required">cl::Required</a>, <a href="#cl::desc">cl::desc</a>("<i><input file></i>"));
-</pre>
+</pre></div>
-By simply adding the <tt><a href="#cl::Required">cl::Required</a></tt> flag, the
-CommandLine library will automatically issue an error if the argument is not
+<p>By simply adding the <tt><a href="#cl::Required">cl::Required</a></tt> flag,
+the CommandLine library will automatically issue an error if the argument is not
specified, which shifts all of the command line option verification code out of
your application into the library. This is just one example of how using flags
can alter the default behaviour of the library, on a per-option basis. By
adding one of the declarations above, the <tt>--help</tt> option synopsis is now
-extended to:<p>
+extended to:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options] <b><input file></b>
OPTIONS:
-help - display available options (--help-hidden for more)
-o <filename> - Specify output filename
-</pre>
-
-... indicating that an input filename is expected.<p>
+</pre></div>
+<p>... indicating that an input filename is expected.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="bool">Boolean Arguments
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="bool">Boolean Arguments</a>
+</div>
+
+<div class="doc_text">
-In addition to input and output filenames, we would like the compiler example to
-support three boolean flags: "<tt>-f</tt>" to force overwriting of the output
+<p>In addition to input and output filenames, we would like the compiler example
+to support three boolean flags: "<tt>-f</tt>" to force overwriting of the output
file, "<tt>--quiet</tt>" to enable quiet mode, and "<tt>-q</tt>" for backwards
compatibility with some of our users. We can support these by declaring options
-of boolean type like this:<p>
+of boolean type like this:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><bool> Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
<a href="#cl::opt">cl::opt</a><bool> Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
<a href="#cl::opt">cl::opt</a><bool> 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>);
-</pre><p>
+</pre></div>
-This does what you would expect: it declares three boolean variables
+<p>This does what you would expect: it declares three boolean variables
("<tt>Force</tt>", "<tt>Quiet</tt>", and "<tt>Quiet2</tt>") to recognize these
options. Note that the "<tt>-q</tt>" option is specified with the "<a
href="#cl::Hidden"><tt>cl::Hidden</tt></a>" flag. This modifier prevents it
from being shown by the standard "<tt>--help</tt>" output (note that it is still
-shown in the "<tt>--help-hidden</tt>" output).<p>
+shown in the "<tt>--help-hidden</tt>" output).</p>
-The CommandLine library uses a <a href="#builtinparsers">different parser</a>
+
<p>The CommandLine library uses a <a href="#builtinparsers">different parser</a>
for different data types. For example, in the string case, the argument passed
to the option is copied literally into the content of the string variable... we
obviously cannot do that in the boolean case, however, so we must use a smarter
parser. In the case of the boolean parser, it allows no options (in which case
it assigns the value of true to the variable), or it allows the values
"<tt>true</tt>" or "<tt>false</tt>" to be specified, allowing any of the
-following inputs:<p>
+following inputs:</p>
-<pre>
+<div class="doc_code"><pre>
compiler -f # No value, 'Force' == true
compiler -f=true # Value specified, 'Force' == true
compiler -f=TRUE # Value specified, 'Force' == true
compiler -f=FALSE # Value specified, 'Force' == false
-</pre>
+</pre></div>
-... you get the idea. The <a href="#boolparser">bool parser</a> just turns the
-string values into boolean values, and rejects things like '<tt>compiler
+<p>... you get the idea. The <a href="#boolparser">bool parser</a> just turns
+the string values into boolean values, and rejects things like '<tt>compiler
-f=foo</tt>'. Similarly, the <a href="#doubleparser">float</a>, <a
href="#doubleparser">double</a>, and <a href="#intparser">int</a> parsers work
like you would expect, using the '<tt>strtol</tt>' and '<tt>strtod</tt>' C
-library calls to parse the string value into the specified data type.<p>
+library calls to parse the string value into the specified data type.</p>
-With the declarations above, "<tt>compiler --help</tt>" emits this:<p>
+<p>With the declarations above, "<tt>compiler --help</tt>" emits this:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options] <input file>
OPTIONS:
-o - Override output filename
<b>-quiet - Don't print informational messages</b>
-help - display available options (--help-hidden for more)
-</pre><p>
+</pre></div>
-and "<tt>opt --help-hidden</tt>" prints this:<p>
+<p>and "<tt>opt --help-hidden</tt>" prints this:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options] <input file>
OPTIONS:
<b>-q - Don't print informational messages</b>
-quiet - Don't print informational messages
-help - display available options (--help-hidden for more)
-</pre><p>
+</pre></div>
-This brief example has shown you how to use the '<tt><a
+
<p>This brief example has shown you how to use the '<tt><a
href="#cl::opt">cl::opt</a></tt>' class to parse simple scalar command line
arguments. In addition to simple scalar arguments, the CommandLine library also
provides primitives to support CommandLine option <a href="#alias">aliases</a>,
-and <a href="#list">lists</a> of options.<p>
+and <a href="#list">lists</a> of options.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="alias">Argument Aliases
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="alias">Argument Aliases</a>
+</div>
-So far, the example works well, except for the fact that we need to check the
-quiet condition like this now:<p>
+<div class="doc_text">
-<pre>
+<p>So far, the example works well, except for the fact that we need to check the
+quiet condition like this now:</p>
+
+<div class="doc_code"><pre>
...
if (!Quiet && !Quiet2) printInformationalMessage(...);
...
-</pre><p>
+</pre></div>
-... which is a real pain! Instead of defining two values for the same
+<p>... which is a real pain! Instead of defining two values for the same
condition, we can use the "<tt><a href="#cl::alias">cl::alias</a></tt>" class to make the "<tt>-q</tt>"
option an <b>alias</b> for the "<tt>-quiet</tt>" option, instead of providing
-a value itself:<p>
+a value itself:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><bool> Force ("<i>f</i>", <a href="#cl::desc">cl::desc</a>("<i>Overwrite output files</i>"));
<a href="#cl::opt">cl::opt</a><bool> Quiet ("<i>quiet</i>", <a href="#cl::desc">cl::desc</a>("<i>Don't print informational messages</i>"));
<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));
-</pre><p>
+</pre></div>
-The third line (which is the only one we modified from above) defines a
+<p>The third line (which is the only one we modified from above) defines a
"<tt>-q</tt> alias that updates the "<tt>Quiet</tt>" variable (as specified by
the <tt><a href="#cl::aliasopt">cl::aliasopt</a></tt> modifier) whenever it is
specified. Because aliases do not hold state, the only thing the program has to
query is the <tt>Quiet</tt> variable now. Another nice feature of aliases is
that they automatically hide themselves from the <tt>-help</tt> output
(although, again, they are still visible in the <tt>--help-hidden
-output</tt>).<p>
+output</tt>).</p>
-Now the application code can simply use:<p>
+<p>Now the application code can simply use:</p>
-<pre>
+<div class="doc_code"><pre>
...
if (!Quiet) printInformationalMessage(...);
...
-</pre><p>
-
-... which is much nicer! The "<tt><a href="#cl::alias">cl::alias</a></tt>" can be used to specify an
-alternative name for any variable type, and has many uses.<p>
+</pre></div>
+<p>... which is much nicer! The "<tt><a href="#cl::alias">cl::alias</a></tt>"
+can be used to specify an alternative name for any variable type, and has many
+uses.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="onealternative">Selecting an alternative from a set of possibilities
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="onealternative">Selecting an alternative from a set of
+ possibilities</a>
+</div>
+
+<div class="doc_text">
-So far, we have seen how the CommandLine library handles builtin types like
+<p>So far, we have seen how the CommandLine library handles builtin types like
<tt>std::string</tt>, <tt>bool</tt> and <tt>int</tt>, but how does it handle
-things it doesn't know about, like enums or '<tt>int*</tt>'s?<p>
+things it doesn't know about, like enums or '<tt>int*</tt>'s?</p>
-The answer is that it uses a table driven generic parser (unless you specify
+<p>The answer is that it uses a table driven generic parser (unless you specify
your own parser, as described in the <a href="#extensionguide">Extension
-Guide</a>). This parser maps literal strings to whatever type is required, are
-requires you to tell it what this mapping should be.<p>
+Guide</a>). This parser maps literal strings to whatever type is required, and
+requires you to tell it what this mapping should be.</p>
-Lets say that we would like to add four optimizations levels to our optimizer,
-using the standard flags "<tt>-g</tt>", "<tt>-O0</tt>", "<tt>-O1</tt>", and
-"<tt>-O2</tt>". We could easily implement this with boolean options like above,
-but there are several problems with this strategy:<p>
+<p>Lets say that we would like to add four optimization levels to our
+optimizer, using the standard flags "<tt>-g</tt>", "<tt>-O0</tt>",
+"<tt>-O1</tt>", and "<tt>-O2</tt>". We could easily implement this with boolean
+options like above, but there are several problems with this strategy:</p>
<ol>
<li>A user could specify more than one of the options at a time, for example,
"<tt>opt -O3 -O2</tt>". The CommandLine library would not be able to catch this
-erroneous input for us.
+erroneous input for us.</li>
-<li>We would have to test 4 different variables to see which ones are set.
+<li>We would have to test 4 different variables to see which ones are set.</li>
<li>This doesn't map to the numeric levels that we want... so we cannot easily
-see if some level >= "<tt>-O1</tt>" is enabled.
+see if some level >= "<tt>-O1</tt>" is enabled.</li>
-</ol><p>
+</ol>
-To cope with these problems, we can use an enum value, and have the CommandLine
-library fill it in with the appropriate level directly, which is used like
-this:<p>
+<p>To cope with these problems, we can use an enum value, and have the
+CommandLine library fill it in with the appropriate level directly, which is
+used like this:</p>
-<pre>
+<div class="doc_code"><pre>
enum OptLevel {
g, O1, O2, O3
};
clEnumVal(O1, "<i>Enable trivial optimizations</i>"),
clEnumVal(O2, "<i>Enable default optimizations</i>"),
clEnumVal(O3, "<i>Enable expensive optimizations</i>"),
- 0));
+ clEnumValEnd));
...
if (OptimizationLevel >= O2) doPartialRedundancyElimination(...);
...
-</pre><p>
+</pre></div>
-This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
+<p>This declaration defines a variable "<tt>OptimizationLevel</tt>" of the
"<tt>OptLevel</tt>" enum type. This variable can be assigned any of the values
that are listed in the declaration (Note that the declaration list must be
-terminated with the "<tt>0</tt>" argument!). The CommandLine library enforces
+terminated with the "<tt>clEnumValEnd</tt>" argument!). The CommandLine
+library enforces
that the user can only specify one of the options, and it ensure that only valid
enum values can be specified. The "<tt>clEnumVal</tt>" macros ensure that the
command line arguments matched the enum values. With this option added, our
-help output now is:<p>
+help output now is:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options] <input file>
OPTIONS:
-help - display available options (--help-hidden for more)
-o <filename> - Specify output filename
-quiet - Don't print informational messages
-</pre>
+</pre></div>
-In this case, it is sort of awkward that flag names correspond directly to enum
-names, because we probably don't want a enum definition named "<tt>g</tt>" in
-our program. Because of this, we can alternatively write this example like
-this:<p>
+<p>In this case, it is sort of awkward that flag names correspond directly to
+enum names, because we probably don't want a enum definition named "<tt>g</tt>"
+in our program. Because of this, we can alternatively write this example like
+this:</p>
-<pre>
+<div class="doc_code"><pre>
enum OptLevel {
Debug, O1, O2, O3
};
clEnumVal(O1 , "<i>Enable trivial optimizations</i>"),
clEnumVal(O2 , "<i>Enable default optimizations</i>"),
clEnumVal(O3 , "<i>Enable expensive optimizations</i>"),
- 0));
+ clEnumValEnd));
...
if (OptimizationLevel == Debug) outputDebugInfo(...);
...
-</pre><p>
-
-By using the "<tt>clEnumValN</tt>" macro instead of "<tt>clEnumVal</tt>", we can
-directly specify the name that the flag should get. In general a direct mapping
-is nice, but sometimes you can't or don't want to preserve the mapping, which is
-when you would use it.<p>
+</pre></div>
+<p>By using the "<tt>clEnumValN</tt>" macro instead of "<tt>clEnumVal</tt>", we
+can directly specify the name that the flag should get. In general a direct
+mapping is nice, but sometimes you can't or don't want to preserve the mapping,
+which is when you would use it.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="namedalternatives">Named Alternatives
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="namedalternatives">Named Alternatives</a>
+</div>
+
+<div class="doc_text">
-Another useful argument form is a named alternative style. We shall use this
+<p>Another useful argument form is a named alternative style. We shall use this
style in our compiler to specify different debug levels that can be used.
Instead of each debug level being its own switch, we want to support the
following options, of which only one can be specified at a time:
"<tt>--debug-level=none</tt>", "<tt>--debug-level=quick</tt>",
"<tt>--debug-level=detailed</tt>". To do this, we use the exact same format as
our optimization level flags, but we also specify an option name. For this
-case, the code looks like this:<p>
+case, the code looks like this:</p>
-<pre>
+<div class="doc_code"><pre>
enum DebugLev {
nodebuginfo, quick, detailed
};
// Enable Debug Options to be specified on the command line
-<a href="#cl::opt">cl::opt</a>
<DebugLev> DebugLevel("<i>debug_level</i>", <a href="#cl::desc">cl::desc</a>("<i>Set the debugging level:</i>"),
+<a href="#cl::opt">cl::opt</a>
<DebugLev> DebugLevel("<i>debug_level</i>", <a href="#cl::desc">cl::desc</a>("<i>Set the debugging level:</i>"),
<a href="#cl::values">cl::values</a>(
clEnumValN(nodebuginfo, "none", "<i>disable debug information</i>"),
clEnumVal(quick, "<i>enable quick debug information</i>"),
clEnumVal(detailed, "<i>enable detailed debug information</i>"),
- 0));
-</pre>
+ clEnumValEnd));
+</pre></div>
-This definition defines an enumerated command line variable of type "<tt>enum
+<p>This definition defines an enumerated command line variable of type "<tt>enum
DebugLev</tt>", which works exactly the same way as before. The difference here
is just the interface exposed to the user of your program and the help output by
-the "<tt>--help</tt>" option:<p>
+the "<tt>--help</tt>" option:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: compiler [options] <input file>
OPTIONS:
-help - display available options (--help-hidden for more)
-o <filename> - Specify output filename
-quiet - Don't print informational messages
-</pre><p>
+</pre></div>
-Again, the only structural difference between the debug level declaration and
-the optimiation level declaration is that the debug level declaration includes
+<p>Again, the only structural difference between the debug level declaration and
+the optimization level declaration is that the debug level declaration includes
an option name (<tt>"debug_level"</tt>), which automatically changes how the
library processes the argument. The CommandLine library supports both forms so
-that you can choose the form most appropriate for your application.<p>
-
+that you can choose the form most appropriate for your application.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="list">Parsing a list of options
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="list">Parsing a list of options</a>
+</div>
-Now that we have the standard run of the mill argument types out of the way,
+<div class="doc_text">
+
+<p>Now that we have the standard run of the mill argument types out of the way,
lets get a little wild and crazy. Lets say that we want our optimizer to accept
a <b>list</b> of optimizations to perform, allowing duplicates. For example, we
might want to run: "<tt>compiler -dce -constprop -inline -dce -strip</tt>". In
this case, the order of the arguments and the number of appearances is very
important. This is what the "<tt><a href="#cl::list">cl::list</a></tt>"
template is for. First, start by defining an enum of the optimizations that you
-would like to perform:<p>
+would like to perform:</p>
-<pre>
+<div class="doc_code"><pre>
enum Opts {
// 'inline' is a C++ keyword, so name it 'inlining'
dce, constprop, inlining, strip
};
-</pre><p>
+</pre></div>
-Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:<p>
+<p>Then define your "<tt><a href="#cl::list">cl::list</a></tt>" variable:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::list">cl::list</a><Opts> OptimizationList(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
<a href="#cl::values">cl::values</a>(
clEnumVal(dce , "<i>Dead Code Elimination</i>"),
clEnumVal(constprop , "<i>Constant Propagation</i>"),
clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
clEnumVal(strip , "<i>Strip Symbols</i>"),
- 0));
-</pre><p>
+ clEnumValEnd));
+</pre></div>
-This defines a variable that is conceptually of the type
+<p>This defines a variable that is conceptually of the type
"<tt>std::vector<enum Opts></tt>". Thus, you can access it with standard
-vector methods:<p>
+vector methods:</p>
-<pre>
+<div class="doc_code"><pre>
for (unsigned i = 0; i != OptimizationList.size(); ++i)
switch (OptimizationList[i])
...
-</pre>
+</pre></div>
-... to iterate through the list of options specified.<p>
+<p>... to iterate through the list of options specified.</p>
-Note that the "<tt><a href="#cl::list">cl::list</a></tt>" template is completely general and may be used
-with any data types or other arguments that you can use with the
-"<tt><a href="#cl::opt">cl::opt</a></tt>" template. One especially useful way to use a list is to
-capture all of the positional arguments together if there may be more than one
-specified. In the case of a linker, for example, the linker takes several
-'<tt>.o</tt>' files, and needs to capture them into a list. This is naturally
-specified as:<p>
+<p>Note that the "<tt><a href="#cl::list">cl::list</a></tt>" template is
+completely general and may be used with any data types or other arguments that
+you can use with the "<tt><a href="#cl::opt">cl::opt</a></tt>" template. One
+especially useful way to use a list is to capture all of the positional
+arguments together if there may be more than one specified. In the case of a
+linker, for example, the linker takes several '<tt>.o</tt>' files, and needs to
+capture them into a list. This is naturally specified as:</p>
-<pre>
+<div class="doc_code"><pre>
...
<a href="#cl::list">cl::list</a><std::string> InputFilenames(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<Input files>"), <a href="#cl::OneOrMore">cl::OneOrMore</a>);
...
-</pre><p>
+</pre></div>
-This variable works just like a "<tt>vector<string></tt>" object. As
+<p>This variable works just like a "<tt>vector<string></tt>" object. As
such, accessing the list is simple, just like above. In this example, we used
the <tt><a href="#cl::OneOrMore">cl::OneOrMore</a></tt> modifier to inform the
CommandLine library that it is an error if the user does not specify any
<tt>.o</tt> files on our command line. Again, this just reduces the amount of
-checking we have to do.<p>
+checking we have to do.</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="bits">Collecting options as a set of flags</a>
+</div>
+
+<div class="doc_text">
+
+<p>Instead of collecting sets of options in a list, it is also possible to
+gather information for enum values in a <b>bit vector</b>. The represention used by
+the <a href="#bits"><tt>cl::bits</tt></a> class is an <tt>unsigned</tt>
+integer. An enum value is represented by a 0/1 in the enum's ordinal value bit
+position. 1 indicating that the enum was specified, 0 otherwise. As each
+specified value is parsed, the resulting enum's bit is set in the option's bit
+vector:</p>
+
+<div class="doc_code"><pre>
+ <i>bits</i> |= 1 << (unsigned)<i>enum</i>;
+</pre></div>
+
+<p>Options that are specified multiple times are redundant. Any instances after
+the first are discarded.</p>
+
+<p>Reworking the above list example, we could replace <a href="#list">
+<tt>cl::list</tt></a> with <a href="#bits"><tt>cl::bits</tt></a>:</p>
+
+<div class="doc_code"><pre>
+<a href="#cl::bits">cl::bits</a><Opts> OptimizationBits(<a href="#cl::desc">cl::desc</a>("<i>Available Optimizations:</i>"),
+ <a href="#cl::values">cl::values</a>(
+ clEnumVal(dce , "<i>Dead Code Elimination</i>"),
+ clEnumVal(constprop , "<i>Constant Propagation</i>"),
+ clEnumValN(inlining, "<i>inline</i>", "<i>Procedure Integration</i>"),
+ clEnumVal(strip , "<i>Strip Symbols</i>"),
+ clEnumValEnd));
+</pre></div>
+
+<p>To test to see if <tt>constprop</tt> was specified, we can use the
+<tt>cl:bits::isSet</tt> function:</p>
+
+<div class="doc_code"><pre>
+ if (OptimizationBits.isSet(constprop)) {
+ ...
+ }
+</pre></div>
+
+<p>It's also possible to get the raw bit vector using the
+<tt>cl::bits::getBits</tt> function:</p>
+
+<div class="doc_code"><pre>
+ unsigned bits = OptimizationBits.getBits();
+</pre></div>
+
+<p>Finally, if external storage is used, then the location specified must be of
+<b>type</b> <tt>unsigned</tt>. In all other ways a <a
+href="#bits"><tt>cl::bits</tt></a> option is morally equivalent to a <a
+href="#list"> <tt>cl::list</tt></a> option.</p>
+
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="description">Adding freeform text to help output
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="description">Adding freeform text to help output</a>
+</div>
-As our program grows and becomes more mature, we may decide to put summary
+<div class="doc_text">
+
+<p>As our program grows and becomes more mature, we may decide to put summary
information about what it does into the help output. The help output is styled
to look similar to a Unix <tt>man</tt> page, providing concise information about
a program. Unix <tt>man</tt> pages, however often have a description about what
href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
call in main. This additional argument is then printed as the overview
information for your program, allowing you to include any additional information
-that you want. For example:<p>
+that you want. For example:</p>
-<pre>
+<div class="doc_code"><pre>
int main(int argc, char **argv) {
<a href="#cl::ParseCommandLineOptions">cl::ParseCommandLineOptions</a>(argc, argv, " CommandLine compiler example\n\n"
" This program blah blah blah...\n");
...
}
-</pre><p>
+</pre></div>
-Would yield the help output:
+<p>would yield the help output:</p>
-<pre>
+<div class="doc_code"><pre>
<b>OVERVIEW: CommandLine compiler example
This program blah blah blah...</b>
...
-help - display available options (--help-hidden for more)
-o <filename> - Specify output filename
-</pre><p>
-
+</pre></div>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="referenceguide">Reference Guide
-</b></font></td></tr></table><ul>
+<div class="doc_section">
+ <a name="referenceguide">Reference Guide</a>
+</div>
<!-- *********************************************************************** -->
-Now that you know the basics of how to use the CommandLine library, this section
-will give you the detailed information you need to tune how command line options
-work, as well as information on more "advanced" command line option processing
-capabilities.<p>
+<div class="doc_text">
+
+<p>Now that you know the basics of how to use the CommandLine library, this
+section will give you the detailed information you need to tune how command line
+options work, as well as information on more "advanced" command line option
+processing capabilities.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="positional">Positional Arguments
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="positional">Positional Arguments</a>
+</div>
-Positional arguments are those arguments that are not named, and are not
+<div class="doc_text">
+
+<p>Positional arguments are those arguments that are not named, and are not
specified with a hyphen. Positional arguments should be used when an option is
specified by its position alone. For example, the standard Unix <tt>grep</tt>
tool takes a regular expression argument, and an optional filename to search
through (which defaults to standard input if a filename is not specified).
-Using the CommandLine library, this would be specified as:<p>
+Using the CommandLine library, this would be specified as:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> Regex (<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i><regular expression></i>"), <a href="#cl::Required">cl::Required</a>);
<a href="#cl::opt">cl::opt</a><string> Filename(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i><input file></i>"), <a href="#cl::init">cl::init</a>("<i>-</i>"));
-</pre>
+</pre></div>
-Given these two option declarations, the <tt>--help</tt> output for our grep
-replacement would look like this:<p>
+<p>Given these two option declarations, the <tt>--help</tt> output for our grep
+replacement would look like this:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: spiffygrep [options] <b><regular expression> <input file></b>
OPTIONS:
-help - display available options (--help-hidden for more)
-</pre>
+</pre></div>
-... and the resultant program could be used just like the standard <tt>grep</tt>
-tool.<p>
+<p>... and the resultant program could be used just like the standard
+<tt>grep</tt> tool.</p>
-Positional arguments are sorted by their order of construction. This means that
-command line options will be ordered according to how they are listed in a .cpp
-file, but will not have an ordering defined if they positional arguments are
-defined in multiple .cpp files. The fix for this problem is simply to define
-all of your positional arguments in one .cpp file.<p>
+<p>Positional arguments are sorted by their order of construction. This means
+that command line options will be ordered according to how they are listed in a
+.cpp file, but will not have an ordering defined if the positional arguments
+are defined in multiple .cpp files. The fix for this problem is simply to
+define all of your positional arguments in one .cpp file.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="--"><h4><hr size=0>Specifying positional options with hyphens</h4><ul>
+<div class="doc_subsubsection">
+ <a name="--">Specifying positional options with hyphens</a>
+</div>
+
+<div class="doc_text">
-Sometimes you may want to specify a value to your positional argument that
+<p>Sometimes you may want to specify a value to your positional argument that
starts with a hyphen (for example, searching for '<tt>-foo</tt>' in a file). At
first, you will have trouble doing this, because it will try to find an argument
named '<tt>-foo</tt>', and will fail (and single quotes will not save you).
-Note that the system <tt>grep</tt> has the same problem:<p>
+Note that the system <tt>grep</tt> has the same problem:</p>
-<pre>
+<div class="doc_code"><pre>
$ spiffygrep '-foo' test.txt
Unknown command line argument '-foo'. Try: spiffygrep --help'
grep: illegal option -- o
grep: illegal option -- o
Usage: grep -hblcnsviw pattern file . . .
-</pre><p>
+</pre></div>
-The solution for this problem is the same for both your tool and the system
+<p>The solution for this problem is the same for both your tool and the system
version: use the '<tt>--</tt>' marker. When the user specifies '<tt>--</tt>' on
the command line, it is telling the program that all options after the
'<tt>--</tt>' should be treated as positional arguments, not options. Thus, we
-can use it like this:<p>
+can use it like this:</p>
-<pre>
+<div class="doc_code"><pre>
$ spiffygrep -- -foo test.txt
...output...
-</pre><p>
+</pre></div>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="getPosition">Determining absolute position with getPosition()</a>
+</div>
+<div class="doc_text">
+ <p>Sometimes an option can affect or modify the meaning of another option. For
+ example, consider <tt>gcc</tt>'s <tt>-x LANG</tt> option. This tells
+ <tt>gcc</tt> to ignore the suffix of subsequent positional arguments and force
+ the file to be interpreted as if it contained source code in language
+ <tt>LANG</tt>. In order to handle this properly , you need to know the
+ absolute position of each argument, especially those in lists, so their
+ interaction(s) can be applied correctly. This is also useful for options like
+ <tt>-llibname</tt> which is actually a positional argument that starts with
+ a dash.</p>
+ <p>So, generally, the problem is that you have two <tt>cl::list</tt> variables
+ that interact in some way. To ensure the correct interaction, you can use the
+ <tt>cl::list::getPosition(optnum)</tt> method. This method returns the
+ absolute position (as found on the command line) of the <tt>optnum</tt>
+ item in the <tt>cl::list</tt>.</p>
+ <p>The idiom for usage is like this:</p>
+
+ <div class="doc_code"><pre>
+ static cl::list<std::string> Files(cl::Positional, cl::OneOrMore);
+ static cl::listlt;std::string> Libraries("l", cl::ZeroOrMore);
+
+ int main(int argc, char**argv) {
+ // ...
+ std::vector<std::string>::iterator fileIt = Files.begin();
+ std::vector<std::string>::iterator libIt = Libraries.begin();
+ unsigned libPos = 0, filePos = 0;
+ while ( 1 ) {
+ if ( libIt != Libraries.end() )
+ libPos = Libraries.getPosition( libIt - Libraries.begin() );
+ else
+ libPos = 0;
+ if ( fileIt != Files.end() )
+ filePos = Files.getPosition( fileIt - Files.begin() );
+ else
+ filePos = 0;
+
+ if ( filePos != 0 && (libPos == 0 || filePos < libPos) ) {
+ // Source File Is next
+ ++fileIt;
+ }
+ else if ( libPos != 0 && (filePos == 0 || libPos < filePos) ) {
+ // Library is next
+ ++libIt;
+ }
+ else
+ break; // we're done with the list
+ }
+ }</pre></div>
+
+ <p>Note that, for compatibility reasons, the <tt>cl::opt</tt> also supports an
+ <tt>unsigned getPosition()</tt> option that will provide the absolute position
+ of that option. You can apply the same approach as above with a
+ <tt>cl::opt</tt> and a <tt>cl::list</tt> option as you can with two lists.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="cl::ConsumeAfter"><h4><hr size=0>The <tt>cl::ConsumeAfter</tt> modifier</h4><ul>
+<div class="doc_subsubsection">
+ <a name="cl::ConsumeAfter">The <tt>cl::ConsumeAfter</tt> modifier</a>
+</div>
-The <tt>cl::ConsumeAfter</tt> <a href="#formatting">formatting option</a> is
+<div class="doc_text">
+
+<p>The <tt>cl::ConsumeAfter</tt> <a href="#formatting">formatting option</a> is
used to construct programs that use "interpreter style" option processing. With
this style of option processing, all arguments specified after the last
positional argument are treated as special interpreter arguments that are not
-interpreted by the command line argument.<p>
+interpreted by the command line argument.</p>
-As a concrete example, lets say we are developing a replacement for the standard
-Unix Bourne shell (<tt>/bin/sh</tt>). To run <tt>/bin/sh</tt>, first you
-specify options to the shell itself (like <tt>-x</tt> which turns on trace
+<p>As a concrete example, lets say we are developing a replacement for the
+standard Unix Bourne shell (<tt>/bin/sh</tt>). To run <tt>/bin/sh</tt>, first
+you specify options to the shell itself (like <tt>-x</tt> which turns on trace
output), then you specify the name of the script to run, then you specify
arguments to the script. These arguments to the script are parsed by the bourne
shell command line option processor, but are not interpreted as options to the
-shell itself. Using the CommandLine library, we would specify this as:<p>
+shell itself. Using the CommandLine library, we would specify this as:</p>
-<pre>
+<div class="doc_code"><pre>
<a href="#cl::opt">cl::opt</a><string> Script(<a href="#cl::Positional">cl::Positional</a>, <a href="#cl::desc">cl::desc</a>("<i><input script></i>"), <a href="#cl::init">cl::init</a>("-"));
<a href="#cl::list">cl::list</a><string> Argv(<a href="#cl::ConsumeAfter">cl::ConsumeAfter</a>, <a href="#cl::desc">cl::desc</a>("<i><program arguments>...</i>"));
<a href="#cl::opt">cl::opt</a><bool> Trace("<i>x</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable trace output</i>"));
-</pre><p>
+</pre></div>
-which automatically provides the help output:<p>
+<p>which automatically provides the help output:</p>
-<pre>
+<div class="doc_code"><pre>
USAGE: spiffysh [options] <b><input script> <program arguments>...</b>
OPTIONS:
-help - display available options (--help-hidden for more)
<b>-x - Enable trace output</b>
-</pre><p>
+</pre></div>
-At runtime, if we run our new shell replacement as '<tt>spiffysh -x test.sh -a
--x -y bar</tt>', the <tt>Trace</tt> variable will be set to true, the
+<p>At runtime, if we run our new shell replacement as `<tt>spiffysh -x test.sh
+-a -x -y bar</tt>', the <tt>Trace</tt> variable will be set to true, the
<tt>Script</tt> variable will be set to "<tt>test.sh</tt>", and the
-<tt>Argv</tt> list will contain <tt>["-a", "-x", "-y", "bar"]</tt>, because
-they were specified after the last positional argument (which is the script
-name).<p>
-
-There are several limitations to when <tt>cl::ConsumeAfter</tt> options can be
-specified. For example, only one <tt>cl::ConsumeAfter</tt> can be specified per
-program, there must be at least one <a href="#positional">positional
-argument</a> specified, and the <tt>cl::ConsumeAfter</tt> option should be a <a
-href="#cl::list">cl::list</a> option.<p>
+<tt>Argv</tt> list will contain <tt>["-a", "-x", "-y", "bar"]</tt>, because they
+were specified after the last positional argument (which is the script
+name).</p>
+<p>There are several limitations to when <tt>cl::ConsumeAfter</tt> options can
+be specified. For example, only one <tt>cl::ConsumeAfter</tt> can be specified
+per program, there must be at least one <a href="#positional">positional
+argument</a> specified, there must not be any <a href="#cl::list">cl::list</a>
+positional arguments, and the <tt>cl::ConsumeAfter</tt> option should be a <a
+href="#cl::list">cl::list</a> option.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="storage">Internal vs External Storage
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="storage">Internal vs External Storage</a>
+</div>
+
+<div class="doc_text">
-By default, all command line options automatically hold the value that they
+<p>By default, all command line options automatically hold the value that they
parse from the command line. This is very convenient in the common case,
especially when combined with the ability to define command line options in the
-files that use them. This is called the internal storage model.<p>
+files that use them. This is called the internal storage model.</p>
-Sometimes, however, it is nice to separate the command line option processing
+<p>Sometimes, however, it is nice to separate the command line option processing
code from the storage of the value parsed. For example, lets say that we have a
'<tt>-debug</tt>' option that we would like to use to enable debug information
across the entire body of our program. In this case, the boolean value
controlling the debug code should be globally accessable (in a header file, for
example) yet the command line option processing code should not be exposed to
all of these clients (requiring lots of .cpp files to #include
-<tt>CommandLine.h</tt>).<p>
+<tt>CommandLine.h</tt>).</p>
-To do this, set up your .h file with your option, like this for example:<p>
+<p>To do this, set up your .h file with your option, like this for example:</p>
+<div class="doc_code">
<pre>
<i>// DebugFlag.h - Get access to the '-debug' command line option
//
// debug build, then the code specified as the option to the macro will be
// executed. Otherwise it will not be. Example:
//
-// DEBUG(cerr << "Bitset contains: " << Bitset << "\n");
+// DOUT << "Bitset contains: " << Bitset << "\n";
//</i>
-<font color=red>#ifdef NDEBUG
+<span class="doc_hilite">#ifdef NDEBUG
#define DEBUG(X)
#else
-#define DEBUG(X)</font> \
- do { if (DebugFlag) { X; } } while (0)
-<font color=red>#endif</font>
+#define DEBUG(X)</span> do { if (DebugFlag) { X; } } while (0)
+<span class="doc_hilite">#endif</span>
</pre>
+</div>
-This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
+<p>This allows clients to blissfully use the <tt>DEBUG()</tt> macro, or the
<tt>DebugFlag</tt> explicitly if they want to. Now we just need to be able to
set the <tt>DebugFlag</tt> boolean when the option is set. To do this, we pass
an additial argument to our command line argument processor, and we specify
-where to fill in with the <a href="#cl::location">cl::location</a> attribute:<p>
+where to fill in with the <a href="#cl::location">cl::location</a>
+attribute:</p>
+<div class="doc_code">
<pre>
-bool DebugFlag; <i>// the actual value</i>
-static <a href="#cl::opt">cl::opt</a><bool, true> <i>// The parser</i>
-Debug("<i>debug</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable debug output</i>")</a>, <a href="#cl::Hidden">cl::Hidden</a>,
- <a href="#cl::location">cl::location</a>(DebugFlag));
+bool DebugFlag; <i>// the actual value</i>
+static <a href="#cl::opt">cl::opt</a><bool, true> <i>// The parser</i>
+Debug("<i>debug</i>", <a href="#cl::desc">cl::desc</a>("<i>Enable debug output</i>"), <a href="#cl::Hidden">cl::Hidden</a>, <a href="#cl::location">cl::location</a>(DebugFlag));
</pre>
+</div>
-In the above example, we specify "<tt>true</tt>" as the second argument to the
-<a href="#cl::opt">cl::opt</a> template, indicating that the template should not
-maintain a copy of the value itself. In addition to this, we specify the <a
-href="#cl::location">cl::location</a> attribute, so that <tt>DebugFlag</tt> is
-automatically set.<p>
-
+<p>In the above example, we specify "<tt>true</tt>" as the second argument to
+the <tt><a href="#cl::opt">cl::opt</a></tt> template, indicating that the
+template should not maintain a copy of the value itself. In addition to this,
+we specify the <tt><a href="#cl::location">cl::location</a></tt> attribute, so
+that <tt>DebugFlag</tt> is automatically set.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="attributes">Option Attributes
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="attributes">Option Attributes</a>
+</div>
-This section describes the basic attributes that you can specify on options.<p>
+<div class="doc_text">
+
+<p>This section describes the basic attributes that you can specify on
+options.</p>
<ul>
<li>The option name attribute (which is required for all options, except <a
href="#positional">positional options</a>) specifies what the option name is.
-This option is specified in simple double quotes:<p>
+This option is specified in simple double quotes:
<pre>
<a href="#cl::opt">cl::opt</a><<b>bool</b>> Quiet("<i>quiet</i>");
-</pre><p>
+</pre>
+
+</li>
-<li><a name="cl::desc">The <b><tt>cl::desc</tt></b> attribute specifies a
+<li><a name="cl::desc">The <b><tt>cl::desc</tt></b></a> attribute specifies a
description for the option to be shown in the <tt>--help</tt> output for the
-program.<p>
+program.</li>
-<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b> attribute
+<li><a name="cl::value_desc">The <b><tt>cl::value_desc</tt></b></a> attribute
specifies a string that can be used to fine tune the <tt>--help</tt> output for
a command line option. Look <a href="#value_desc_example">here</a> for an
-example.<p>
+example.</li>
-<li><a name="cl::init">The <b><tt>cl::init</tt></b> attribute specifies an
+<li><a name="cl::init">The <b><tt>cl::init</tt></b></a> attribute specifies an
inital value for a <a href="#cl::opt">scalar</a> option. If this attribute is
not specified then the command line option value defaults to the value created
-by the default constructor for the type.<p>
-
-<li><a name="cl::location">The <b><tt>cl::location</tt></b> attribute where to
+by the default constructor for the type. <b>Warning</b>: If you specify both
+<b><tt>cl::init</tt></b> and <b><tt>cl::location</tt></b> for an option,
+you must specify <b><tt>cl::location</tt></b> first, so that when the
+command-line parser sees <b><tt>cl::init</tt></b>, it knows where to put the
+initial value. (You will get an error at runtime if you don't put them in
+the right order.)</li>
+
+<li><a name="cl::location">The <b><tt>cl::location</tt></b></a> attribute where to
store the value for a parsed command line option if using external storage. See
the section on <a href="#storage">Internal vs External Storage</a> for more
-information.<p>
+information.</li>
+
+<li><a name="cl::aliasopt">The <b><tt>cl::aliasopt</tt></b></a> attribute
+specifies which option a <tt><a href="#cl::alias">cl::alias</a></tt> option is
+an alias for.</li>
-<li><a name="cl::aliasopt">The <b><tt>cl::aliasopt</tt></b> attribute specifies
-which option a <a href="#cl::alias">cl::alias</a> option is an alias for.<p>
+<li><a name="cl::values">The <b><tt>cl::values</tt></b></a> attribute specifies
+the string-to-value mapping to be used by the generic parser. It takes a
+<b>clEnumValEnd terminated</b> list of (option, value, description) triplets
+that
+specify the option name, the value mapped to, and the description shown in the
+<tt>--help</tt> for the tool. Because the generic parser is used most
+frequently with enum values, two macros are often useful:
-<li><a name="cl::values">The <b><tt>cl::values</tt></b> attribute specifies the
-string-to-value mapping to be used by the generic parser. It takes a <b>null
-terminated</b> list of (option, value, description) triplets that specify the
-option name, the value mapped to, and the description shown in the
-<tt>--help</tt> for the tool. Because the generic parser is used most frequently with enum values, two macros are often useful:<p>
<ol>
-<li><a name="clEnumVal">The <b><tt>clEnumVal</tt></b> macro is used as a nice
-simple way to specify a triplet for an enum. This macro automatically makes the
-option name be the same as the enum name. The first option to the macro is the
-enum, the second is the description for the command line option.<p> <li><a
-name="clEnumValN">The <b><tt>clEnumValN</tt></b> macro is used to specify macro
-options where the option name doesn't equal the enum name. For this macro, the
-first argument is the enum value, the second is the flag name, and the second is
-the description.<p>
+
+<li><a name="clEnumVal">The <b><tt>clEnumVal</tt></b></a> macro is used as a
+nice simple way to specify a triplet for an enum. This macro automatically
+makes the option name be the same as the enum name. The first option to the
+macro is the enum, the second is the description for the command line
+option.</li>
+
+<li><a name="clEnumValN">The <b><tt>clEnumValN</tt></b></a> macro is used to
+specify macro options where the option name doesn't equal the enum name. For
+this macro, the first argument is the enum value, the second is the flag name,
+and the second is the description.</li>
+
</ol>
You will get a compile time error if you try to use cl::values with a parser
-that does not support it.<p>
+that does not support it.</li>
</ul>
-
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="modifiers">Option Modifiers
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="modifiers">Option Modifiers</a>
+</div>
-Option modifiers are the flags and expressions that you pass into the
+<div class="doc_text">
+
+<p>Option modifiers are the flags and expressions that you pass into the
constructors for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
href="#cl::list">cl::list</a></tt>. These modifiers give you the ability to
tweak how options are parsed and how <tt>--help</tt> output is generated to fit
-your application well.<p>
+your application well.</p>
-These options fall into five main catagories:<p>
+<p>These options fall into five main catagories:</p>
<ol>
-<li><a href="#hiding">Hiding an option from <tt>--help</tt> output</a>
-<li><a href="#numoccurances">Controlling the number of occurances
- required and allowed</a>
+<li><a href="#hiding">Hiding an option from <tt>--help</tt> output</a></li>
+<li><a href="#numoccurrences">Controlling the number of occurrences
+ required and allowed</a></li>
<li><a href="#valrequired">Controlling whether or not a value must be
- specified</a>
-<li><a href="#formatting">Controlling other formatting options</a>
-<li><a href="#misc">Miscellaneous option modifiers</a>
-</ol><p>
+ specified</a></li>
+<li><a href="#formatting">Controlling other formatting options</a></li>
+<li><a href="#misc">Miscellaneous option modifiers</a></li>
+</ol>
-It is not possible to specify two options from the same catagory (you'll get a
-runtime error) to a single option, except for options in the miscellaneous
+<p>It is not possible to specify two options from the same catagory (you'll get
+a runtime error) to a single option, except for options in the miscellaneous
catagory. The CommandLine library specifies defaults for all of these settings
that are the most useful in practice and the most common, which mean that you
-usually shouldn't have to worry about these.<p>
+usually shouldn't have to worry about these.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="hiding"><h4><hr size=0>Hiding an option from <tt>--help</tt> output</h4><ul>
+<div class="doc_subsubsection">
+ <a name="hiding">Hiding an option from <tt>--help</tt> output</a>
+</div>
+
+<div class="doc_text">
-The <tt>cl::NotHidden</tt>, <tt>cl::Hidden</tt>, and <tt>cl::ReallyHidden</tt>
-modifiers are used to control whether or not an option appears in the
-<tt>--help</tt> and <tt>--help-hidden</tt> output for the compiled program:<p>
+<p>The <tt>cl::NotHidden</tt>, <tt>cl::Hidden</tt>, and
+<tt>cl::ReallyHidden</tt> modifiers are used to control whether or not an option
+appears in the <tt>--help</tt> and <tt>--help-hidden</tt> output for the
+compiled program:</p>
<ul>
-<a name="cl::NotHidden">The <b><tt>cl::NotHidden</tt></b> modifier (which is the
-default for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
+<li><a name="cl::NotHidden">The <b><tt>cl::NotHidden</tt></b></a> modifier
+
(which is the default for <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
href="#cl::list">cl::list</a></tt> options), indicates the option is to appear
-in both help listings.<p>
+in both help listings.</li>
-<a name="cl::Hidden">The <b><tt>cl::Hidden</tt></b> modifier (which is the
+<li><a name="cl::Hidden">The <b><tt>cl::Hidden</tt></b></a> modifier (which is the
default for <tt><a href="#cl::alias">cl::alias</a></tt> options), indicates that
the option should not appear in the <tt>--help</tt> output, but should appear in
-the <tt>--help-hidden</tt> output.<p>
+the <tt>--help-hidden</tt> output.</li>
+
+<li><a name="cl::ReallyHidden">The <b><tt>cl::ReallyHidden</tt></b></a> modifier,
+indicates that the option should not appear in any help output.</li>
-<a name="cl::ReallyHidden">The <b><tt>cl::ReallyHidden</tt></b> modifier,
-indicates that the option should not appear in any help output.<p>
</ul>
+</div>
+
<!-- _______________________________________________________________________ -->
-</ul><a name="numoccurances"><h4><hr size=0>Controlling the number of occurances required and allowed</h4><ul>
+<div class="doc_subsubsection">
+ <a name="numoccurrences">Controlling the number of occurrences required and
+ allowed</a>
+</div>
-This group of options is used to control how many time an option is allowed (or
-required) to be specified on the command line of your program. Specifying a
+<div class="doc_text">
+
+<p>This group of options is used to control how many time an option is allowed
+(or required) to be specified on the command line of your program. Specifying a
value for this setting allows the CommandLine library to do error checking for
-you.<p>
+you.</p>
-The allowed values for this option group are:<p>
+<p>The allowed values for this option group are:</p>
<ul>
-<a name="cl::Optional">The <b><tt>cl::Optional</tt></b> modifier (which is the
-default for the <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
+
+<li><a name="cl::Optional">The <b><tt>cl::Optional</tt></b></a> modifier (which
+is the default for the <tt><a href="#cl::opt">cl::opt</a></tt> and <tt><a
href="#cl::alias">cl::alias</a></tt> classes) indicates that your program will
-allow either zero or one occurance of the option to be specified.<p>
+allow either zero or one occurrence of the option to be specified.</li>
-<a name="cl::ZeroOrMore">The <b><tt>cl::ZeroOrMore</tt></b> modifier (which is
-the default for the <tt><a href="#cl::list">cl::list</a></tt> class) indicates
-that your program will allow the option to be specified zero or more times.<p>
+<li><a name="cl::ZeroOrMore">The <b><tt>cl::ZeroOrMore</tt></b></a> modifier
+(which is the default for the <tt><a href="#cl::list">cl::list</a></tt> class)
+indicates that your program will allow the option to be specified zero or more
+times.</li>
-<a name="cl::Required">The <b><tt>cl::Required</tt></b> modifier indicates that
-the specified option must be specified exactly one time.<p>
+<li><a name="cl::Required">The <b><tt>cl::Required</tt></b></a> modifier
+indicates that the specified option must be specified exactly one time.</li>
-<a name="cl::OneOrMore">The <b><tt>cl::OneOrMore</tt></b> modifier indicates
-that the option must be specified at least one time.<p>
+<li><a name="cl::OneOrMore">The <b><tt>cl::OneOrMore</tt></b></a> modifier
+indicates that the option must be specified at least one time.</li>
-The <b><tt>cl::ConsumeAfter</tt></b> modifier is described in the <a
-href="#positional">Positional arguments section</a><p>
+
<li>The <b><tt>cl::ConsumeAfter</tt></b> modifier is described in the <a
+href="#positional">Positional arguments section</a></li>
</ul>
-If an option is not specified, then the value of the option is equal to the
+<p>If an option is not specified, then the value of the option is equal to the
value specified by the <tt><a href="#cl::init">cl::init</a></tt> attribute. If
the <tt><a href="#cl::init">cl::init</a></tt> attribute is not specified, the
-option value is initialized with the default constructor for the data type.<p>
+option value is initialized with the default constructor for the data type.</p>
-If an option is specified multiple times for an option of the <tt><a
-href="#cl::opt">cl::opt</a></tt> class, only the last value will be retained.<p>
+<p>If an option is specified multiple times for an option of the <tt><a
+href="#cl::opt">cl::opt</a></tt> class, only the last value will be
+retained.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="valrequired"><h4><hr size=0>Controlling whether or not a value must be specified</h4><ul>
+<div class="doc_subsubsection">
+ <a name="valrequired">Controlling whether or not a value must be specified</a>
+</div>
+
+<div class="doc_text">
-This group of options is used to control whether or not the option allows a
+<p>This group of options is used to control whether or not the option allows a
value to be present. In the case of the CommandLine library, a value is either
specified with an equal sign (e.g. '<tt>-index-depth=17</tt>') or as a trailing
-string (e.g. '<tt>-o a.out</tt>').<p>
+string (e.g. '<tt>-o a.out</tt>').</p>
-The allowed values for this option group are:<p>
+<p>The allowed values for this option group are:</p>
<ul>
-<a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b> modifier
+
+<li><a name="cl::ValueOptional">The <b><tt>cl::ValueOptional</tt></b></a> modifier
(which is the default for <tt>bool</tt> typed options) specifies that it is
acceptable to have a value, or not. A boolean argument can be enabled just by
appearing on the command line, or it can have an explicit '<tt>-foo=true</tt>'.
If an option is specified with this mode, it is illegal for the value to be
provided without the equal sign. Therefore '<tt>-foo true</tt>' is illegal. To
get this behavior, you must use the <a
-href="#cl::ValueRequired">cl::ValueRequired</a> modifier.<p>
+href="#cl::ValueRequired">cl::ValueRequired</a> modifier.</li>
-<a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b> modifier
+<li><a name="cl::ValueRequired">The <b><tt>cl::ValueRequired</tt></b></a> modifier
(which is the default for all other types except for <a
href="#onealternative">unnamed alternatives using the generic parser</a>)
specifies that a value must be provided. This mode informs the command line
library that if an option is not provides with an equal sign, that the next
argument provided must be the value. This allows things like '<tt>-o
-a.out</tt>' to work.<p>
+a.out</tt>' to work.</li>
-<a name="cl::ValueDisallowed">The <b><tt>cl::ValueDisallowed</tt></b> modifier
-(which is the default for <a href="#onealternative">unnamed alternatives using
-the generic parser</a>) indicates that it is a runtime error for the user to specify a value. This can be provided to disallow users from providing options to boolean options (like '<tt>-foo=true</tt>').<p>
+<li><a name="cl::ValueDisallowed">The <b><tt>cl::ValueDisallowed</tt></b></a>
+modifier (which is the default for <a href="#onealternative">unnamed
+alternatives using the generic parser</a>) indicates that it is a runtime error
+for the user to specify a value. This can be provided to disallow users from
+providing options to boolean options (like '<tt>-foo=true</tt>').</li>
</ul>
-In general, the default values for this option group work just like you would
+<p>In general, the default values for this option group work just like you would
want them to. As mentioned above, you can specify the <a
href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier to a boolean
argument to restrict your command line parser. These options are mostly useful
-when <a href="#extensionguide">extending the library</a>.<p>
-
+when <a href="#extensionguide">extending the library</a>.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="formatting"><h4><hr size=0>Controlling other formatting options</h4><ul>
+<div class="doc_subsubsection">
+ <a name="formatting">Controlling other formatting options</a>
+</div>
+
+<div class="doc_text">
-The formatting option group is used to specify that the command line option has
-special abilities and is otherwise different from other command line arguments.
-As usual, you can only specify at most one of these arguments.<p>
+<p>The formatting option group is used to specify that the command line option
+has special abilities and is otherwise different from other command line
+arguments. As usual, you can only specify at most one of these arguments.</p>
<ul>
-<a name="cl::NormalFormatting">The <b><tt>cl::NormalFormatting</tt></b> modifier
-(which is the default all options) specifies that this option is "normal".<p>
-
-<a name="cl::Positional">The <b><tt>cl::Positional</tt></b> modifier specifies
-that this is a positional argument, that does not have a command line option
-associated with it. See the <a href="#positional">Positional Arguments</a>
-section for more information.<p>
-
-The <b><a href="#cl::ConsumeAfter"><tt>cl::ConsumeAfter</tt></a></b> modifier
-specifies that this option is used to capture "interpreter style" arguments. See <a href="#cl::ConsumeAfter">this section for more information</a>.<p>
-
-
-<a name="cl::Prefix">The <b><tt>cl::Prefix</tt></b> modifier specifies that this
-option prefixes its value. With 'Prefix' options, there is no equal sign that
-seperates the value from the option name specified. This is useful for
-processing odd arguments like '<tt>-lmalloc -L/usr/lib'</tt> in a linker tool.
-Here, the '<tt>l</tt>' and '<tt>L</tt>' options are normal string (list)
-options, that have the <a href="#cl::Prefix">cl::Prefix</a> modifier added to
-allow the CommandLine library to recognize them. Note that <a
-href="#cl::Prefix">cl::Prefix</a> options must not have the <a
-href="#cl::ValueDisallowed">cl::ValueDisallowed</a> modifier specified.<p>
-
-<a name="cl::Grouping">The <b><tt>cl::Grouping</tt></b> modifier is used to
-implement unix style tools (like <tt>ls</tt>) that have lots of single letter
+
+<li><a name="cl::NormalFormatting">The <b><tt>cl::NormalFormatting</tt></b></a>
+modifier (which is the default all options) specifies that this option is
+"normal".</li>
+
+<li><a name="cl::Positional">The <b><tt>cl::Positional</tt></b></a> modifier
+specifies that this is a positional argument, that does not have a command line
+option associated with it. See the <a href="#positional">Positional
+Arguments</a> section for more information.</li>
+
+<li>The <b><a href="#cl::ConsumeAfter"><tt>cl::ConsumeAfter</tt></a></b> modifier
+specifies that this option is used to capture "interpreter style" arguments. See <a href="#cl::ConsumeAfter">this section for more information</a>.</li>
+
+<li><a name="cl::Prefix">The <b><tt>cl::Prefix</tt></b></a> modifier specifies
+that this option prefixes its value. With 'Prefix' options, the equal sign does
+not separate the value from the option name specified. Instead, the value is
+everything after the prefix, including any equal sign if present. This is useful
+for processing odd arguments like <tt>-lmalloc</tt> and <tt>-L/usr/lib</tt> in a
+linker tool or <tt>-DNAME=value</tt> in a compiler tool. Here, the
+'<tt>l</tt>', '<tt>D</tt>' and '<tt>L</tt>' options are normal string (or list)
+options, that have the <b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b>
+modifier added to allow the CommandLine library to recognize them. Note that
+<b><tt><a href="#cl::Prefix">cl::Prefix</a></tt></b> options must not have the
+<b><tt><a href="#cl::ValueDisallowed">cl::ValueDisallowed</a></tt></b> modifier
+specified.</li>
+
+<li><a name="cl::Grouping">The <b><tt>cl::Grouping</tt></b></a> modifier is used
+to implement unix style tools (like <tt>ls</tt>) that have lots of single letter
arguments, but only require a single dash. For example, the '<tt>ls -labF</tt>'
command actually enables four different options, all of which are single
-letters. Note that <a href="#cl::Grouping">cl::Grouping</a> options cannot have
-values.<p>
+letters. Note that <b><tt><a href="#cl::Grouping">cl::Grouping</a></tt></b>
+options cannot have values.</li>
</ul>
-The CommandLine library does not restrict how you use the <a
-href="#cl::Prefix">cl::Prefix</a> or <a href="#cl::Grouping">cl::Grouping</a>
-modifiers, but it is possible to specify ambiguous argument settings. Thus, it
-is possible to have multiple letter options that are prefix or grouping options,
-and they will still work as designed.<p>
+<p>The CommandLine library does not restrict how you use the <b><tt><a
+href="#cl::Prefix">cl::Prefix</a></tt></b> or <b><tt><a
+href="#cl::Grouping">cl::Grouping</a></tt></b> modifiers, but it is possible to
+specify ambiguous argument settings. Thus, it is possible to have multiple
+letter options that are prefix or grouping options, and they will still work as
+designed.</p>
+
+<p>To do this, the CommandLine library uses a greedy algorithm to parse the
+input option into (potentially multiple) prefix and grouping options. The
+strategy basically looks like this:</p>
-To do this, the CommandLine library uses a greedy algorithm to parse the input
-option into (potentially multiple) prefix and grouping options. The strategy
-basically looks like this:<p>
+<div class="doc_code"><tt>parse(string OrigInput) {</tt>
-<tt>parse(string OrigInput) {</tt>
<ol>
<li><tt>string input = OrigInput;</tt>
<li><tt>if (isOption(input)) return getOption(input).parse();</tt> <i>// Normal option</i>
input = OrigInput;<br>
while (!isOption(input) && !input.empty()) input.pop_back();<br>
}</tt>
-<li><tt>if (!OrigInput.empty()) error();</tt>
-</tt>
-
+<li><tt>if (!OrigInput.empty()) error();</tt></li>
</ol>
-<tt>}</tt><p>
+<p><tt>}</tt></p>
+</div>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="misc"><h4><hr size=0>Miscellaneous option modifiers</h4><ul>
+<div class="doc_subsubsection">
+ <a name="misc">Miscellaneous option modifiers</a>
+</div>
-The miscellaneous option modifiers are the only flags where you can specify more
-than one flag from the set: they are not mutually exclusive. These flags
-specify boolean properties that modify the option.<p>
+<div class="doc_text">
+
+<p>The miscellaneous option modifiers are the only flags where you can specify
+more than one flag from the set: they are not mutually exclusive. These flags
+specify boolean properties that modify the option.</p>
<ul>
-<a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b> modifier
+<li><a name="cl::CommaSeparated">The <b><tt>cl::CommaSeparated</tt></b></a> modifier
indicates that any commas specified for an option's value should be used to
split the value up into multiple values for the option. For example, these two
options are equivalent when <tt>cl::CommaSeparated</tt> is specified:
"<tt>-foo=a -foo=b -foo=c</tt>" and "<tt>-foo=a,b,c</tt>". This option only
makes sense to be used in a case where the option is allowed to accept one or
-more values (i.e. it is a <a href="#cl::list">cl::list</a> option).<p>
+more values (i.e. it is a <a href="#cl::list">cl::list</a> option).</li>
+
+<li><a name="cl::PositionalEatsArgs">The
+<b><tt>cl::PositionalEatsArgs</tt></b></a> modifier (which only applies to
+positional arguments, and only makes sense for lists) indicates that positional
+argument should consume any strings after it (including strings that start with
+a "-") up until another recognized positional argument. For example, if you
+have two "eating" positional arguments "<tt>pos1</tt>" and "<tt>pos2</tt>" the
+string "<tt>-pos1 -foo -bar baz -pos2 -bork</tt>" would cause the "<tt>-foo -bar
+-baz</tt>" strings to be applied to the "<tt>-pos1</tt>" option and the
+"<tt>-bork</tt>" string to be applied to the "<tt>-pos2</tt>" option.</li>
+
</ul>
-So far, the only miscellaneous option modifier is the
-<tt>cl::CommaSeparated</tt> modifier.<p>
+<p>So far, these are the only two miscellaneous option modifiers.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="toplevel">Top-Level Classes and Functions
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="toplevel">Top-Level Classes and Functions</a>
+</div>
-Despite all of the builtin flexibility, the CommandLine option library really
-only consists of one function (<a
+<div class="doc_text">
+
+<p>Despite all of the built-in flexibility, the CommandLine option library
+really only consists of one function (<a
href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>)
and three main classes: <a href="#cl::opt"><tt>cl::opt</tt></a>, <a
href="#cl::list"><tt>cl::list</tt></a>, and <a
href="#cl::alias"><tt>cl::alias</tt></a>. This section describes these three
-classes in detail.<p>
+classes in detail.</p>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="cl::ParseCommandLineOptions"><h4><hr size=0>The
-<tt>cl::ParseCommandLineOptions</tt> function</h4><ul>
+<div class="doc_subsubsection">
+ <a name="cl::ParseCommandLineOptions">The <tt>cl::ParseCommandLineOptions</tt>
+ function</a>
+</div>
+
+<div class="doc_text">
-The <tt>cl::ParseCommandLineOptions</tt> function is designed to be called
+<p>The <tt>cl::ParseCommandLineOptions</tt> function is designed to be called
directly from <tt>main</tt>, and is used to fill in the values of all of the
command line option variables once <tt>argc</tt> and <tt>argv</tt> are
-available.<p>
+available.</p>
-The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
+<p>The <tt>cl::ParseCommandLineOptions</tt> function requires two parameters
(<tt>argc</tt> and <tt>argv</tt>), but may also take an optional third parameter
which holds <a href="#description">additional extra text</a> to emit when the
-<tt>--help</tt> option is invoked.<p>
+<tt>--help</tt> option is invoked.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="cl::opt"><h4><hr size=0>The <tt>cl::opt</tt> class</h4><ul>
+<div class="doc_subsubsection">
+ <a name="cl::ParseEnvironmentOptions">The <tt>cl::ParseEnvironmentOptions</tt>
+ function</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>cl::ParseEnvironmentOptions</tt> function has mostly the same effects
+as <a
+href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>,
+except that it is designed to take values for options from an environment
+variable, for those cases in which reading the command line is not convenient or
+not desired. It fills in the values of all the command line option variables
+just like <a
+href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>
+does.</p>
+
+<p>It takes three parameters: first, the name of the program (since
+<tt>argv</tt> may not be available, it can't just look in <tt>argv[0]</tt>),
+second, the name of the environment variable to examine, and third, the optional
+<a href="#description">additional extra text</a> to emit when the
+<tt>--help</tt> option is invoked.</p>
+
+<p><tt>cl::ParseEnvironmentOptions</tt> will break the environment
+variable's value up into words and then process them using
+<a href="#cl::ParseCommandLineOptions"><tt>cl::ParseCommandLineOptions</tt></a>.
+<b>Note:</b> Currently <tt>cl::ParseEnvironmentOptions</tt> does not support
+quoting, so an environment variable containing <tt>-option "foo bar"</tt> will
+be parsed as three words, <tt>-option</tt>, <tt>"foo</tt>, and <tt>bar"</tt>,
+which is different from what you would get from the shell with the same
+input.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="cl::SetVersionPrinter">The <tt>cl::SetVersionPrinter</tt>
+ function</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>cl::SetVersionPrinter</tt> function is designed to be called
+directly from <tt>main</tt>, and <i>before</i>
+<tt>cl::ParseCommandLineOptions</tt>. Its use is optional. It simply arranges
+for a function to be called in response to the <tt>--version</tt> option instead
+of having the <tt>CommandLine</tt> library print out the usual version string
+for LLVM. This is useful for programs that are not part of LLVM but wish to use
+the <tt>CommandLine</tt> facilities. Such programs should just define a small
+function that takes no arguments and returns <tt>void</tt> and that prints out
+whatever version information is appropriate for the program. Pass the address
+of that function to <tt>cl::SetVersionPrinter</tt> to arrange for it to be
+called when the <tt>--version</tt> option is given by the user.</p>
+
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="cl::opt">The <tt>cl::opt</tt> class</a>
+</div>
+
+<div class="doc_text">
-The <tt>cl::opt</tt> class is the class used to represent scalar command line
+<p>The <tt>cl::opt</tt> class is the class used to represent scalar command line
options, and is the one used most of the time. It is a templated class which
can take up to three arguments (all except for the first have default values
-though):<p>
+though):</p>
-<pre>
+<div class="doc_code"><pre>
<b>namespace</b> cl {
<b>template</b> <<b>class</b> DataType, <b>bool</b> ExternalStorage = <b>false</b>,
<b>class</b> ParserClass = parser<DataType> >
<b>class</b> opt;
}
-</pre><p>
+</pre></div>
-The first template argument specifies what underlying data type the command line
-argument is, and is used to select a default parser implementation. The second
-template argument is used to specify whether the option should contain the
-storage for the option (the default) or whether external storage should be used
-to contain the value parsed for the option (see <a href="#storage">Internal vs
-External Storage</a> for more information).<p>
+<p>The first template argument specifies what underlying data type the command
+line argument is, and is used to select a default parser implementation. The
+second template argument is used to specify whether the option should contain
+the storage for the option (the default) or whether external storage should be
+used to contain the value parsed for the option (see <a href="#storage">Internal
+vs External Storage</a> for more information).</p>
-The third template argument specifies which parser to use. The default value
+<p>The third template argument specifies which parser to use. The default value
selects an instantiation of the <tt>parser</tt> class based on the underlying
data type of the option. In general, this default works well for most
applications, so this option is only used when using a <a
-href="#customparser">custom parser</a>.<p>
+href="#customparser">custom parser</a>.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="cl::list"><h4><hr size=0>The <tt>cl::list</tt> class</h4><ul>
+<div class="doc_subsubsection">
+ <a name="cl::list">The <tt>cl::list</tt> class</a>
+</div>
+
+<div class="doc_text">
-The <tt>cl::list</tt> class is the class used to represent a list of command
+<p>The <tt>cl::list</tt> class is the class used to represent a list of command
line options. It too is a templated class which can take up to three
-arguments:<p>
+arguments:</p>
-<pre>
+<div class="doc_code"><pre>
<b>namespace</b> cl {
<b>template</b> <<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
<b>class</b> ParserClass = parser<DataType> >
<b>class</b> list;
}
-</pre><p>
+</pre></div>
-This class works the exact same as the <a href="#cl::opt"><tt>cl::opt</tt></a>
-class, except that the second argument is the <b>type</b> of the external
-storage, not a boolean value. For this class, the marker type '<tt>bool</tt>'
-is used to indicate that internal storage should be used.<p>
+<p>This class works the exact same as the <a
+href="#cl::opt"><tt>cl::opt</tt></a> class, except that the second argument is
+the <b>type</b> of the external storage, not a boolean value. For this class,
+the marker type '<tt>bool</tt>' is used to indicate that internal storage should
+be used.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="cl::alias"><h4><hr size=0>The <tt>cl::alias</tt> class</h4><ul>
+<div class="doc_subsubsection">
+ <a name="cl::bits">The <tt>cl::bits</tt> class</a>
+</div>
-The <tt>cl::alias</tt> class is a nontemplated class that is used to form
-aliases for other arguments.<p>
+<div class="doc_text">
-<pre>
+<p>The <tt>cl::bits</tt> class is the class used to represent a list of command
+line options in the form of a bit vector. It is also a templated class which
+can take up to three arguments:</p>
+
+<div class="doc_code"><pre>
+<b>namespace</b> cl {
+ <b>template</b> <<b>class</b> DataType, <b>class</b> Storage = <b>bool</b>,
+ <b>class</b> ParserClass = parser<DataType> >
+ <b>class</b> bits;
+}
+</pre></div>
+
+<p>This class works the exact same as the <a
+href="#cl::opt"><tt>cl::lists</tt></a> class, except that the second argument
+must be of <b>type</b> <tt>unsigned</tt> if external storage is used.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="cl::alias">The <tt>cl::alias</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>cl::alias</tt> class is a nontemplated class that is used to form
+aliases for other arguments.</p>
+
+<div class="doc_code"><pre>
<b>namespace</b> cl {
<b>class</b> alias;
}
-</pre></p>
+</pre></div>
+
+<p>The <a href="#cl::aliasopt"><tt>cl::aliasopt</tt></a> attribute should be
+used to specify which option this is an alias for. Alias arguments default to
+being <a href="#cl::Hidden">Hidden</a>, and use the aliased options parser to do
+the conversion from string to data.</p>
-The <a href="#cl::aliasopt"><tt>cl::aliasopt</tt></a> attribute should be used
-to specify which option this is an alias for. Alias arguments default to being
-<a href="#cl::Hidden">Hidden</a>, and use the aliased options parser to do the
-conversion from string to data.<p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="cl::extrahelp">The <tt>cl::extrahelp</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>cl::extrahelp</tt> class is a nontemplated class that allows extra
+help text to be printed out for the <tt>--help</tt> option.</p>
+
+<div class="doc_code"><pre>
+<b>namespace</b> cl {
+ <b>struct</b> extrahelp;
+}
+</pre></div>
+
+<p>To use the extrahelp, simply construct one with a <tt>const char*</tt>
+parameter to the constructor. The text passed to the constructor will be printed
+at the bottom of the help message, verbatim. Note that multiple
+<tt>cl::extrahelp</tt> <b>can</b> be used, but this practice is discouraged. If
+your tool needs to print additional help information, put all that help into a
+single <tt>cl::extrahelp</tt> instance.</p>
+<p>For example:</p>
+<div class="doc_code"><pre>
+ cl::extrahelp("\nADDITIONAL HELP:\n\n This is the extra help\n");
+</pre></div>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="builtinparsers">Builtin parsers
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="builtinparsers">Builtin parsers</a>
+</div>
-Parsers control how the string value taken from the command line is translated
-into a typed value, suitable for use in a C++ program. By default, the
-CommandLine library uses an instance of <tt>parser<type></tt> if the
+<div class="doc_text">
+
+<p>Parsers control how the string value taken from the command line is
+translated into a typed value, suitable for use in a C++ program. By default,
+the CommandLine library uses an instance of <tt>parser<type></tt> if the
command line option specifies that it uses values of type '<tt>type</tt>'.
Because of this, custom option processing is specified with specializations of
-the '<tt>parser</tt>' class.<p>
+the '<tt>parser</tt>' class.</p>
+
+<p>The CommandLine library provides the following builtin parser
+specializations, which are sufficient for most applications. It can, however,
+also be extended to work with new data types and new ways of interpreting the
+same data. See the <a href="#customparser">Writing a Custom Parser</a> for more
+details on this type of library extension.</p>
-The CommandLine library provides the following builtin parser specializations,
-which are sufficient for most applications. It can, however, also be extended to
-work with new data types and new ways of interpreting the same data. See the <a
-href="#customparser">Writing a Custom Parser</a> for more details on this type
-of library extension.<p>
+<ul>
-<li><a name="genericparser">The <b>generic <tt>parser<t></tt> parser</b>
+<li><a name="genericparser">The <b>generic <tt>parser<t></tt> parser</b></a>
can be used to map strings values to any data type, through the use of the <a
href="#cl::values">cl::values</a> property, which specifies the mapping
information. The most common use of this parser is for parsing enum values,
which allows you to use the CommandLine library for all of the error checking to
make sure that only valid enum values are specified (as opposed to accepting
arbitrary strings). Despite this, however, the generic parser class can be used
-for any data type.<p>
+for any data type.</li>
-<li><a name="boolparser">The <b><tt>parser<bool></tt> specialization</b>
+<li><a name="boolparser">The <b><tt>parser<bool></tt> specialization</b></a>
is used to convert boolean strings to a boolean value. Currently accepted
strings are "<tt>true</tt>", "<tt>TRUE</tt>", "<tt>True</tt>", "<tt>1</tt>",
-"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".<p>
+"<tt>false</tt>", "<tt>FALSE</tt>", "<tt>False</tt>", and "<tt>0</tt>".</li>
-<li><a name="stringparser">The <b><tt>parser<string></tt> specialization</b> simply stores the parsed string into the string value specified. No conversion or modification of the data is performed.<p>
+<li><a name="boolOrDefaultparser">The <b><tt>parser<boolOrDefault></tt>
+ specialization</b></a> is used for cases where the value is boolean,
+but we also need to know whether the option was specified at all. boolOrDefault
+is an enum with 3 values, BOU_UNSET, BOU_TRUE and BOU_FALSE. This parser accepts
+the same strings as <b><tt>parser<bool></tt></b>.</li>
-<li><a name="intparser">The <b><tt>parser<int></tt> specialization</b>
+<li><a name="stringparser">The <b><tt>parser<string></tt>
+specialization</b></a> simply stores the parsed string into the string value
+specified. No conversion or modification of the data is performed.</li>
+
+<li><a name="intparser">The <b><tt>parser<int></tt> specialization</b></a>
uses the C <tt>strtol</tt> function to parse the string input. As such, it will
accept a decimal number (with an optional '+' or '-' prefix) which must start
with a non-zero digit. It accepts octal numbers, which are identified with a
'<tt>0</tt>' prefix digit, and hexadecimal numbers with a prefix of
-'<tt>0x</tt>' or '<tt>0X</tt>'.<p>
+'<tt>0x</tt>' or '<tt>0X</tt>'.</li>
-<li><a name="doubleparser">The <b><tt>parser<double></tt></b> and
+<li><a name="doubleparser">The <b><tt>parser<double></tt></b></a> and
<b><tt>parser<float></tt> specializations</b> use the standard C
<tt>strtod</tt> function to convert floating point strings into floating point
values. As such, a broad range of string formats is supported, including
exponential notation (ex: <tt>1.7e15</tt>) and properly supports locales.
-<p>
+</li>
+</ul>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0><tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="extensionguide">Extension Guide
-</b></font></td></tr></table><ul>
+<div class="doc_section">
+ <a name="extensionguide">Extension Guide</a>
+</div>
<!-- *********************************************************************** -->
-Although the CommandLine library has a lot of functionality built into it
+<div class="doc_text">
+
+<p>Although the CommandLine library has a lot of functionality built into it
already (as discussed previously), one of its true strengths lie in its
extensibility. This section discusses how the CommandLine library works under
-the covers and illustrates how to do some simple, common, extensions.<p>
+the covers and illustrates how to do some simple, common, extensions.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF"
-face="Georgia,Palatino"><b> <a name="customparser">Writing a custom parser
-</b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="customparser">Writing a custom parser</a>
+</div>
-One of the simplest and most common extensions is the use of a custom parser.
+<div class="doc_text">
+
+<p>One of the simplest and most common extensions is the use of a custom parser.
As <a href="#builtinparsers">discussed previously</a>, parsers are the portion
of the CommandLine library that turns string input from the user into a
-particular parsed data type, validating the input in the process.<p>
+particular parsed data type, validating the input in the process.</p>
-There are two ways to use a new parser:<p>
+<p>There are two ways to use a new parser:</p>
<ol>
-<li>Specialize the <a href="#genericparser"><tt>cl::parser</tt></a> template for
- your custom data type.<p>
- This approach has the advantage that users of your custom data type will
- automatically use your custom parser whenever they define an option with a
- value type of your data type. The disadvantage of this approach is that it
- doesn't work if your fundemental data type is something that is already
- supported.<p>
+<li>
+
+<p>Specialize the <a href="#genericparser"><tt>cl::parser</tt></a> template for
+your custom data type.<p>
+
+<p>This approach has the advantage that users of your custom data type will
+automatically use your custom parser whenever they define an option with a value
+type of your data type. The disadvantage of this approach is that it doesn't
+work if your fundamental data type is something that is already supported.</p>
+
+</li>
+
+<li>
-<li>Write an independant class, using it explicitly from options that need
- it.<p>
+<p>Write an independent class, using it explicitly from options that need
+it.</p>
- This approach works well in situations where you would line to parse an
- option using special syntax for a not-very-special data-type. The drawback
- of this approach is that users of your parser have to be aware that they are
- using your parser, instead of the builtin ones.<p>
+<p>This approach works well in situations where you would line to parse an
+option using special syntax for a not-very-special data-type. The drawback of
+this approach is that users of your parser have to be aware that they are using
+your parser, instead of the builtin ones.</p>
-</ol><p>
+</li>
-To guide the discussion, we will discuss a custom parser that accepts file
+</ol>
+
+<p>To guide the discussion, we will discuss a custom parser that accepts file
sizes, specified with an optional unit after the numeric size. For example, we
would like to parse "102kb", "41M", "1G" into the appropriate integer value. In
this case, the underlying data type we want to parse into is
'<tt>unsigned</tt>'. We choose approach #2 above because we don't want to make
-this the default for all <tt>unsigned</tt> options.<p>
+this the default for all <tt>unsigned</tt> options.</p>
-To start out, we declare our new <tt>FileSizeParser</tt> class:<p>
+<p>To start out, we declare our new <tt>FileSizeParser</tt> class:</p>
-<pre>
+<div class="doc_code"><pre>
<b>struct</b> FileSizeParser : <b>public</b> cl::basic_parser<<b>unsigned</b>> {
<i>// parse - Return true on error.</i>
<b>bool</b> parse(cl::Option &O, <b>const char</b> *ArgName, <b>const</b> std::string &ArgValue,
<b>unsigned</b> &Val);
};
-</pre><p>
+</pre></div>
-Our new class inherits from the <tt>cl::basic_parser</tt> template class to fill
-in the default, boiler plate, code for us. We give it the data type that we
-parse into (the last argument to the <tt>parse</tt> method so that clients of
+<p>Our new class inherits from the <tt>cl::basic_parser</tt> template class to
+fill in the default, boiler plate, code for us. We give it the data type that
+we parse into (the last argument to the <tt>parse</tt> method so that clients of
our custom parser know what object type to pass in to the parse method (here we
-declare that we parse into '<tt>unsigned</tt>' variables.<p>
+declare that we parse into '<tt>unsigned</tt>' variables.</p>
-For most purposes, the only method that must be implemented in a custom parser
-is the <tt>parse</tt> method. The <tt>parse</tt> method is called whenever the
-option is invoked, passing in the option itself, the option name, the string to
-parse, and a reference to a return value. If the string to parse is not well formed, the parser should output an error message and return true. Otherwise it should return false and set '<tt>Val</tt>' to the parsed value. In our example, we implement <tt>parse</tt> as:<p>
+<p>For most purposes, the only method that must be implemented in a custom
+parser is the <tt>parse</tt> method. The <tt>parse</tt> method is called
+whenever the option is invoked, passing in the option itself, the option name,
+the string to parse, and a reference to a return value. If the string to parse
+is not well formed, the parser should output an error message and return true.
+Otherwise it should return false and set '<tt>Val</tt>' to the parsed value. In
+our example, we implement <tt>parse</tt> as:</p>
-<pre>
+<div class="doc_code"><pre>
<b>bool</b> FileSizeParser::parse(cl::Option &O, <b>const char</b> *ArgName,
<b>const</b> std::string &Arg, <b>unsigned</b> &Val) {
<b>const char</b> *ArgStart = Arg.c_str();
}
}
}
-</pre><p>
+</pre></div>
-This function implements a very simple parser for the kinds of strings we are
+<p>This function implements a very simple parser for the kinds of strings we are
interested in. Although it has some holes (it allows "<tt>123KKK</tt>" for
example), it is good enough for this example. Note that we use the option
itself to print out the error message (the <tt>error</tt> method always returns
true) in order to get a nice error message (shown below). Now that we have our
-parser class, we can use it like this:<p>
+parser class, we can use it like this:</p>
-<pre>
+<div class="doc_code"><pre>
<b>static</b> <a href="#cl::opt">cl::opt</a><<b>unsigned</b>, <b>false</b>, FileSizeParser>
MFS(<i>"max-file-size"</i>, <a href="#cl::desc">cl::desc</a>(<i>"Maximum file size to accept"</i>),
<a href="#cl::value_desc">cl::value_desc</a>("<i>size</i>"));
-</pre><p>
+</pre></div>
-Which adds this to the output of our program:<p>
+<p>Which adds this to the output of our program:</p>
-<pre>
+<div class="doc_code"><pre>
OPTIONS:
-help - display available options (--help-hidden for more)
...
<b>-max-file-size=<size> - Maximum file size to accept</b>
-</pre><p>
+</pre></div>
-And we can test that our parse works correctly now (the test program just prints
-out the max-file-size argument value):<p>
+<p>And we can test that our parse works correctly now (the test program just
+prints out the max-file-size argument value):</p>
-<pre>
+<div class="doc_code"><pre>
$ ./test
MFS: 0
$ ./test -max-file-size=123MB
MFS: 3221225472
$ ./test -max-file-size=dog
-max-file-size option: 'dog' value invalid for file size argument!
-</pre><p>
+</pre></div>
-It looks like it works. The error message that we get is nice and helpful, and
-we seem to accept reasonable file sizes. This wraps up the "custom parser"
-tutorial.<p>
+<p>It looks like it works. The error message that we get is nice and helpful,
+and we seem to accept reasonable file sizes. This wraps up the "custom parser"
+tutorial.</p>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF"
-face="Georgia,Palatino"><b> <a name="explotingexternal">Exploiting external
-storage </b></font></td></tr></table><ul>
+<div class="doc_subsection">
+ <a name="explotingexternal">Exploiting external storage</a>
+</div>
+<div class="doc_text">
+ <p>Several of the LLVM libraries define static <tt>cl::opt</tt> instances that
+ will automatically be included in any program that links with that library.
+ This is a feature. However, sometimes it is necessary to know the value of the
+ command line option outside of the library. In these cases the library does or
+ should provide an external storage location that is accessible to users of the
+ library. Examples of this include the <tt>llvm::DebugFlag</tt> exported by the
+ <tt>lib/Support/Debug.cpp</tt> file and the <tt>llvm::TimePassesIsEnabled</tt>
+ flag exported by the <tt>lib/VMCore/Pass.cpp</tt> file.</p>
+<p>TODO: complete this section</p>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF"
-face="Georgia,Palatino"><b> <a name="dynamicopts">Dynamically adding command
-line options </b></font></td></tr></table><ul>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="dynamicopts">Dynamically adding command line options</a>
+</div>
+<div class="doc_text">
+<p>TODO: fill in this section</p>
+</div>
-<!-- *********************************************************************** -->
-</ul>
<!-- *********************************************************************** -->
<hr>
-<font size=-1>
-<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
-<!-- Created: Tue Jan 23 15:19:28 CST 2001 -->
-<!-- hhmts start -->
-Last modified: Thu May 22 15:35:19 CDT 2003
-<!-- hhmts end -->
-</font>
-</body></html>
+<address>
+ <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
+ src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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+ src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
+
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
+ <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
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