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<h1>Module <a href="type_Cmdliner.html">Cmdliner</a></h1>

<pre><span class="keyword">module</span> Cmdliner: <code class="code"><span class="keyword">sig</span></code> <a href="Cmdliner.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info module top">
Declarative definition of command line interfaces.
<p>

    <code class="code"><span class="constructor">Cmdliner</span></code> provides a simple and compositional mechanism
    to convert command line arguments to OCaml values and pass them to
    your functions. The module automatically handles syntax errors,
    help messages and UNIX man page generation. It supports programs 
    with single or multiple commands
    (like <code class="code">darcs</code> or <code class="code">git</code>) and respect most of the
    <a href="http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap12.html">
    POSIX</a> and
    <a href="http://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html">
    GNU</a> conventions.
<p>

    Consult the <a href="Cmdliner.html#basics">basics</a>, details about the supported
    <a href="Cmdliner.html#cmdline">command line syntax</a> and <a href="Cmdliner.html#examples"> examples</a> of
    use. Open the module to use it, it defines only three modules in
    your scope.
<p>

    <em>Release 0.9.4 - Daniel Bünzli &lt;daniel.buenzl i@erratique.ch&gt; </em><br>
</div>
<hr width="100%">
<br>
<h1 id="top">Interface</h1><br>

<pre><span class="keyword">module</span> <a href="Cmdliner.Manpage.html">Manpage</a>: <code class="code"><span class="keyword">sig</span></code> <a href="Cmdliner.Manpage.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info">
Man page specification.
</div>

<pre><span class="keyword">module</span> <a href="Cmdliner.Term.html">Term</a>: <code class="code"><span class="keyword">sig</span></code> <a href="Cmdliner.Term.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info">
Terms.
</div>

<pre><span class="keyword">module</span> <a href="Cmdliner.Arg.html">Arg</a>: <code class="code"><span class="keyword">sig</span></code> <a href="Cmdliner.Arg.html">..</a> <code class="code"><span class="keyword">end</span></code></pre><div class="info">
Terms for command line arguments.
</div>
<br>
<h1 id="basics">Basics</h1>
<p>

    With <code class="code"><span class="constructor">Cmdliner</span></code> your program evaluates a term. A <em>term</em>
    is a value of type <a href="Cmdliner.Term.html#TYPEt"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.t</code></a>. The type parameter indicates
    the type of the result of the evaluation.
<p>

    One way to create terms is by lifting regular OCaml values with
    <a href="Cmdliner.Term.html#VALpure"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.pure</code></a>. Terms can be applied to terms evaluating to
    functional values with <a href="Cmdliner.Term.html#VAL($)"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.($)</code></a> (the type for terms is an
    <a href="http://dx.doi.org/10.1017/S0956796807006326">applicative
    functor</a>). For example for the function:
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;revolt&nbsp;()&nbsp;=&nbsp;print_endline&nbsp;<span class="string">"Revolt!"</span></code></pre>
    the term :
<pre class="codepre"><code class="code"><span class="keyword">open</span>&nbsp;<span class="constructor">Cmdliner</span>;;<br>
<br>
<span class="keyword">let</span>&nbsp;revolt_t&nbsp;=&nbsp;<span class="constructor">Term</span>.(pure&nbsp;revolt&nbsp;$&nbsp;pure&nbsp;())</code></pre>
    is a term that evaluates to the result (and effect) of the <code class="code">revolt</code> 
    function.
    Terms are evaluated with <a href="Cmdliner.Term.html#VALeval"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.eval</code></a>:
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval&nbsp;(revolt_t,&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"revolt"</span>)&nbsp;<span class="keyword">with</span>&nbsp;<br>
<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0</code></pre>
    This defines a command line program named <code class="code"><span class="string">"revolt"</span></code>, without command line 
    arguments arguments, that just prints <code class="code"><span class="string">"Revolt!"</span></code> on <code class="code">stdout</code>.
<pre class="codepre"><code class="code">&gt;&nbsp;./revolt&nbsp;<br>
<span class="constructor">Revolt</span>!</code></pre>
    The combinators in the <a href="Cmdliner.Arg.html"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span></code></a> module allow to extract command
    line argument data as terms. These terms can then be applied to
    lifted OCaml functions to be evaluated by the program. 
<p>

    Terms corresponding to command line argument data that are part of
    a term evaluation implicitly define a command line syntax.  We
    show this on an concrete example.
<p>

    Consider the <code class="code">chorus</code> function that prints repeatedly a 
    given message :
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;chorus&nbsp;count&nbsp;msg&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">for</span>&nbsp;i&nbsp;=&nbsp;1&nbsp;<span class="keyword">to</span>&nbsp;count&nbsp;<span class="keyword">do</span>&nbsp;print_endline&nbsp;msg&nbsp;<span class="keyword">done</span></code></pre>
    we want to make it available from the command line
    with the synopsis:
<pre class="codepre"><code class="code">chorus&nbsp;[-c&nbsp;<span class="constructor">COUNT</span>&nbsp;<span class="keywordsign">|</span>&nbsp;--count=<span class="constructor">COUNT</span>]&nbsp;[<span class="constructor">MSG</span>]</code></pre>
    where <code class="code"><span class="constructor">COUNT</span></code> defaults to <code class="code">10</code> and <code class="code"><span class="constructor">MSG</span></code> defaults to <code class="code"><span class="string">"Revolt!"</span></code>. 
    We first define a term corresponding to the <code class="code">--count</code>
    option:
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;count&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Repeat&nbsp;the&nbsp;message&nbsp;$(docv)&nbsp;times."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;int&nbsp;10&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"c"</span>;&nbsp;<span class="string">"count"</span>]&nbsp;~docv:<span class="string">"COUNT"</span>&nbsp;~doc)<br>
</code></pre>
    This says that <code class="code">count</code> is a term that evaluates to the 
    value of an optional argument of type <code class="code">int</code> that 
    defaults to <code class="code">10</code> if unspecified and whose option name is
    either <code class="code">-c</code> or <code class="code">--count</code>. The arguments <code class="code">doc</code> and <code class="code">docv</code> are used to 
    generate the option's man page information. 
<p>

    The term for the positional argument <code class="code"><span class="constructor">MSG</span></code> is:
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;msg&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"The&nbsp;message&nbsp;to&nbsp;print."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;pos&nbsp;0&nbsp;string&nbsp;<span class="string">"Revolt!"</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"MSG"</span>&nbsp;~doc)<br>
</code></pre>
    which says that <code class="code">msg</code> is a term whose value is 
    the positional argument at index <code class="code">0</code> of type <code class="code">string</code> and
    defaults to <code class="code"><span class="string">"Revolt!"</span></code> if unspecified. Here again
    <code class="code">doc</code> and <code class="code">docv</code> are used for the man page information.
<p>

    The term for executing <code class="code">chorus</code> with these command line arguments
    is : 
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;chorus_t&nbsp;=&nbsp;<span class="constructor">Term</span>.(pure&nbsp;chorus&nbsp;$&nbsp;count&nbsp;$&nbsp;msg)<br>
</code></pre>
    and we are now ready to define our program:
<pre class="codepre"><code class="code"><span class="keyword">let</span>&nbsp;info&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"print&nbsp;a&nbsp;customizable&nbsp;message&nbsp;repeatedly"</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;[&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"BUGS"</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Email&nbsp;bug&nbsp;reports&nbsp;to&nbsp;&lt;hehey&nbsp;at&nbsp;example.org&gt;."</span>;]&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"chorus"</span>&nbsp;~version:<span class="string">"1.6.1"</span>&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval&nbsp;(chorus_t,&nbsp;info)&nbsp;<span class="keyword">with</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0<br>
</code></pre>
    The <code class="code">info</code> value created with <a href="Cmdliner.Term.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.info</code></a> gives more information
    about the term we execute and is used to generate the program's
    man page. Since we provided a <code class="code">~version</code> string, the program will
    automatically respond to the <code class="code">--version</code> option by printing this
    string.
<p>

    A program using <a href="Cmdliner.Term.html#VALeval"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.eval</code></a> always responds to the
    <code class="code">--help</code> option by showing the man page about the program generated
    using the information you provided with <a href="Cmdliner.Term.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.info</code></a> and <a href="Cmdliner.Arg.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.info</code></a>.
    Here is the output generated by our example :
<pre class="verbatim">&gt; ./chorus --help
NAME
       chorus - print a customizable message repeatedly

SYNOPSIS
       chorus [OPTION]... [MSG]

ARGUMENTS
       MSG (absent=Revolt!)
           The message to print.

OPTIONS
       -c COUNT, --count=COUNT (absent=10)
           Repeat the message COUNT times.

       --help[=FMT] (default=pager)
           Show this help in format FMT (pager, plain or groff).

       --version
           Show version information.

BUGS
       Email bug reports to &lt;hehey at example.org&gt;.</pre>
<p>

    If a pager is available, this output is written to a pager.
    This help is also available in plain text or in the 
    <a href="http://www.gnu.org/software/groff/groff.html">groff</a> man page format by 
    invoking the program with the option <code class="code">--help=plain</code> or <code class="code">--help=groff</code>. 
<p>

    For examples of more complex command line definitions look and 
    run the <a href="Cmdliner.html#examples">examples</a>.
<p>

    <h2 id="2_Multipleterms">Multiple terms</h2> 
<p>

    <code class="code"><span class="constructor">Cmdliner</span></code> also provides support for programs like <code class="code">darcs</code> or
    <code class="code">git</code> that have multiple commands each with their own syntax:
    <pre class="codepre"><code class="code">prog&nbsp;<span class="constructor">COMMAND</span>&nbsp;[<span class="constructor">OPTION</span>]...&nbsp;<span class="constructor">ARG</span>...</code></pre>
    A command is defined by coupling a term with 
    <a href="Cmdliner.Term.html#tinfo">term information</a>. The term information defines the 
    command name and its man page. Given a list of commands the function
    <a href="Cmdliner.Term.html#VALeval_choice"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.eval_choice</code></a> will execute the term corresponding to the
    <code class="code"><span class="constructor">COMMAND</span></code> argument or or a specific "main" term if there is
    no <code class="code"><span class="constructor">COMMAND</span></code> argument.
<p>

    <h2 id="2_Manual">Manual</h2>
<p>

    Man page sections are printed in the order specified by
    <a href="Cmdliner.Term.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.info</code></a>. The man page information of an argument is listed in
    alphabetical order at the end of the text of the section specified
    by its <a href="Cmdliner.Arg.html#VALinfo">argument information</a>. Positional arguments are
    also listed iff both the <code class="code">docv</code> and <code class="code">doc</code> string is specified in
    their argument information.
<p>

    If an argument information mentions a section not specified in
    <a href="Cmdliner.Term.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.info</code></a>, an empty section is created for it. This section is
    inserted just after the <code class="code"><span class="string">"SYNOPSIS"</span></code> section or after a section
    named <code class="code"><span class="string">"DESCRIPTION"</span></code> if there is one. 
<p>

    The <code class="code"><span class="string">"SYNOPSIS"</span></code> section of a man page is generated automatically
    from a term's information and its arguments. To substitute your
    own instead, start the term's information man page with 
    a <code class="code"><span class="string">"SYNOPSIS"</span></code> section. 
<p>

    Ideally all manual strings should be UTF-8 encoded. However at the
    moment Groff (at least <code class="code">1.19.2</code>) doesn't seem to cope with UTF-8
    input and UTF-8 characters beyond the ASCII set will look garbled.
    Regarding UTF-8 output, generating the man page with <code class="code">-<span class="constructor">Tutf8</span></code> maps
    the hyphen-minus <code class="code"><span class="constructor">U</span>+002<span class="constructor">D</span></code> to the minus sign <code class="code"><span class="constructor">U</span>+2212</code> which makes it 
    difficult to search it in the pager, so <code class="code">-<span class="constructor">Tascii</span></code> is used for now. 
    Conclusion is that it may be better to stick to the ASCII set for now. 
    Please contact the author if something seems wrong in this reasoning 
    or if you know a work around this.
<p>

    <h2 id="2_Miscellaneous">Miscellaneous</h2>
<p>

    <ul>
<li>The option name <code class="code">--help</code>, (and <code class="code">--version</code> if you specify a 
       version string) is reserved by the module. Using it as a term or 
       option name may result in undefined behaviour.</li>
<li>The evaluation of a term in which the same option name is defined
       by more than one argument is undefined.</li>
</ul>

<p>

    <h1 id="cmdline">Command line syntax</h1>
<p>

    For programs evaluating a single term the most general form of invocation 
    is:
    <ul>
<li><code class="code">prog [<span class="constructor">OPTION</span>]... [<span class="constructor">ARG</span>]...</code></li>
</ul>

    The program automatically reponds to the <code class="code">--help</code> option by 
    printing the help. If a version string is provided in 
    the <a href="Cmdliner.Term.html#tinfo">term information</a>, it also automatically responds
    to the <code class="code">--version</code> option by printing this string.
<p>

    Command line arguments are either <a href="Cmdliner.html#optargs"><em>optional</em></a> or
    <a href="Cmdliner.html#posargs"><em>positional</em></a>. Both can be freely interleaved but
    since <code class="code"><span class="constructor">Cmdliner</span></code> accepts many optional forms this may result in
    ambiguities. The special <a href="Cmdliner.html#posargs"> token <code class="code">--</code></a> can be used to resolve 
    them.
<p>

    Programs evaluating multiple terms also add this form of invocation:
    <ul>
<li><code class="code">prog <span class="constructor">COMMAND</span> [<span class="constructor">OPTION</span>]... [<span class="constructor">ARG</span>]...</code></li>
</ul>

    Commands automatically respond to the <code class="code">--help</code> option
    by printing their help. The <code class="code"><span class="constructor">COMMAND</span></code> string must
    be the first string following the program name and may be specified
    by a prefix as long as it is not ambiguous. 
<p>

    <h2 id="optargs">Optional arguments</h2> 
<p>

    An optional argument is specified on the command line by a <em>    name</em> possibly followed by a <em>value</em>.
<p>

    The name of an option can be short or long.
    <ul>
<li>A <em>short</em> name is a dash followed by a single alphanumeric 
       character: <code class="code"><span class="string">"-h"</span></code>, <code class="code"><span class="string">"-q"</span></code>, <code class="code"><span class="string">"-I"</span></code>.</li>
<li>A <em>long</em> name is two dashes followed by alphanumeric 
       characters and dashes: <code class="code"><span class="string">"--help"</span></code>, <code class="code"><span class="string">"--silent"</span></code>, <code class="code"><span class="string">"--ignore-case"</span></code>.</li>
</ul>

<p>

    More than one name may refer to the same optional argument.  For
    example in a given program the names <code class="code"><span class="string">"-q"</span></code>, <code class="code"><span class="string">"--quiet"</span></code> and
    <code class="code"><span class="string">"--silent"</span></code> may all stand for the same boolean argument
    indicating the program to be quiet.  Long names
    can be specified by any non ambiguous prefix. 
<p>

    The value of an option can be specified in three different ways.
    <ul>
<li>As the next token on the command line: <code class="code"><span class="string">"-o a.out"</span></code>, 
       <code class="code"><span class="string">"--output a.out"</span></code>.</li>
<li>Glued to a short name: <code class="code"><span class="string">"-oa.out"</span></code>.</li>
<li>Glued to a long name after an equal character:
    <code class="code"><span class="string">"--output=a.out"</span></code>.</li>
</ul>

    Glued forms are especially useful if
    the value itself starts with a dash as is the case for negative numbers,
    <code class="code"><span class="string">"--min=-10"</span></code>.
<p>

    An optional argument without a value is either a <em>flag</em> 
    (see <a href="Cmdliner.Arg.html#VALflag"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.flag</code></a>, <a href="Cmdliner.Arg.html#VALvflag"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.vflag</code></a>) or an optional argument with an optional 
    value (see the <code class="code">~vopt</code> argument of <a href="Cmdliner.Arg.html#VALopt"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.opt</code></a>). 
<p>

    <h2 id="posargs">Positional arguments</h2>
<p>

    Positional arguments are tokens on the command line that are not
    option names and are not the value of an optional argument. They
    are numbered from left to right starting with zero.
<p>

    Since positional arguments may be mistaken as the optional value
    of an optional argument or they may need to look like option
    names, anything that follows the special token <code class="code"><span class="string">"--"</span></code> on the command
    line is considered to be a positional argument.
<p>

    <h1 id="examples">Examples</h1>
<p>

    These examples are in the <code class="code">test</code> directory of the distribution.
<p>

 <h2 id="exrm">A <code class="code">rm</code> command</h2> 
<p>

    We define the command line interface of a
    <code class="code">rm</code> command with the synopsis:
<pre class="codepre"><code class="code">rm&nbsp;[<span class="constructor">OPTION</span>]...&nbsp;<span class="constructor">FILE</span>...<br>
</code></pre>
    The <code class="code">-f</code>, <code class="code">-i</code> and <code class="code">-<span class="constructor">I</span></code> flags define the prompt behaviour of <code class="code">rm</code>,
    represented in our program by the <code class="code">prompt</code> type. If more than one
    of these flags is present on the command line the last one takes
    precedence.
<p>

    To implement this behaviour we map the presence of these flags
    to values of the <code class="code">prompt</code> type by using <a href="Cmdliner.Arg.html#VALvflag_all"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.vflag_all</code></a>.  This
    argument will contain all occurences of the flag on the command
    line and we just take the <a href="Cmdliner.Arg.html#VALlast"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.last</code></a> one to define our term value
    (if there's no occurence the last value of the default list <code class="code">[<span class="constructor">Always</span>]</code> is
    taken, i.e. the default is <code class="code"><span class="constructor">Always</span></code>).
<pre class="codepre"><code class="code"><span class="comment">(*&nbsp;Implementation&nbsp;of&nbsp;the&nbsp;command,&nbsp;we&nbsp;just&nbsp;print&nbsp;the&nbsp;args.&nbsp;*)</span><br>
<br>
<span class="keyword">type</span>&nbsp;prompt&nbsp;=&nbsp;<span class="constructor">Always</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Once</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Never</span><br>
<span class="keyword">let</span>&nbsp;prompt_str&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<br>
<span class="keywordsign">|</span>&nbsp;<span class="constructor">Always</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"always"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Once</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"once"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Never</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"never"</span><br>
<br>
<span class="keyword">let</span>&nbsp;rm&nbsp;prompt&nbsp;recurse&nbsp;files&nbsp;=<br>
&nbsp;&nbsp;<span class="constructor">Printf</span>.printf&nbsp;<span class="string">"prompt&nbsp;=&nbsp;%s\nrecurse&nbsp;=&nbsp;%b\nfiles&nbsp;=&nbsp;%s\n"</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;(prompt_str&nbsp;prompt)&nbsp;recurse&nbsp;(<span class="constructor">String</span>.concat&nbsp;<span class="string">",&nbsp;"</span>&nbsp;files)<br>
<br>
<span class="comment">(*&nbsp;Command&nbsp;line&nbsp;interface&nbsp;*)</span><br>
<br>
<span class="keyword">open</span>&nbsp;<span class="constructor">Cmdliner</span>;;<br>
<br>
<span class="keyword">let</span>&nbsp;files&nbsp;=&nbsp;<span class="constructor">Arg</span>.(non_empty&nbsp;<span class="keywordsign">&amp;</span>&nbsp;pos_all&nbsp;file&nbsp;[]&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"FILE"</span>)<br>
<span class="keyword">let</span>&nbsp;prompt&nbsp;=<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Prompt&nbsp;before&nbsp;every&nbsp;removal."</span>&nbsp;<span class="keyword">in</span>&nbsp;&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;always&nbsp;=&nbsp;<span class="constructor">Always</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"i"</span>]&nbsp;~doc&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Ignore&nbsp;nonexistent&nbsp;files&nbsp;and&nbsp;never&nbsp;prompt."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;never&nbsp;=&nbsp;<span class="constructor">Never</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"f"</span>;&nbsp;<span class="string">"force"</span>]&nbsp;~doc&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Prompt&nbsp;once&nbsp;before&nbsp;removing&nbsp;more&nbsp;than&nbsp;three&nbsp;files,&nbsp;or&nbsp;when<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;removing&nbsp;recursively.&nbsp;Less&nbsp;intrusive&nbsp;than&nbsp;$(b,-i),&nbsp;while&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;still&nbsp;giving&nbsp;protection&nbsp;against&nbsp;most&nbsp;mistakes."</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;once&nbsp;=&nbsp;<span class="constructor">Once</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"I"</span>]&nbsp;~doc&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(last&nbsp;<span class="keywordsign">&amp;</span>&nbsp;vflag_all&nbsp;[<span class="constructor">Always</span>]&nbsp;[always;&nbsp;never;&nbsp;once])<br>
<br>
<span class="keyword">let</span>&nbsp;recursive&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Remove&nbsp;directories&nbsp;and&nbsp;their&nbsp;contents&nbsp;recursively."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"r"</span>;&nbsp;<span class="string">"R"</span>;&nbsp;<span class="string">"recursive"</span>]&nbsp;~doc)<br>
<br>
<span class="keyword">let</span>&nbsp;cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"remove&nbsp;files&nbsp;or&nbsp;directories"</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;[<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"DESCRIPTION"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(tname)&nbsp;removes&nbsp;each&nbsp;specified&nbsp;$(i,FILE).&nbsp;By&nbsp;default&nbsp;it&nbsp;does&nbsp;not&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;remove&nbsp;directories,&nbsp;to&nbsp;also&nbsp;remove&nbsp;them&nbsp;and&nbsp;their&nbsp;contents,&nbsp;use&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;option&nbsp;$(b,--recursive)&nbsp;($(b,-r)&nbsp;or&nbsp;$(b,-R))."</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"To&nbsp;remove&nbsp;a&nbsp;file&nbsp;whose&nbsp;name&nbsp;starts&nbsp;with&nbsp;a&nbsp;`-',&nbsp;for&nbsp;example<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;`-foo',&nbsp;use&nbsp;one&nbsp;of&nbsp;these&nbsp;commands:"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"rm&nbsp;--&nbsp;-foo"</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">Noblank</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"rm&nbsp;./-foo"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(tname)&nbsp;removes&nbsp;symbolic&nbsp;links,&nbsp;not&nbsp;the&nbsp;files&nbsp;referenced&nbsp;by&nbsp;the&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;links."</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"BUGS"</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Report&nbsp;bugs&nbsp;to&nbsp;&lt;hehey&nbsp;at&nbsp;example.org&gt;."</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"SEE&nbsp;ALSO"</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(b,rmdir)(1),&nbsp;$(b,unlink)(2)"</span>&nbsp;]&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(pure&nbsp;rm&nbsp;$&nbsp;prompt&nbsp;$&nbsp;recursive&nbsp;$&nbsp;files),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"rm"</span>&nbsp;~version:<span class="string">"1.6.1"</span>&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval&nbsp;cmd&nbsp;<span class="keyword">with</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0<br>
</code></pre>
    <h2 id="excp">A <code class="code">cp</code> command</h2> 
<p>

    We define the command line interface of a
    <code class="code">cp</code> command with the synopsis:
<pre class="codepre"><code class="code">cp&nbsp;[<span class="constructor">OPTION</span>]...&nbsp;<span class="constructor">SOURCE</span>...&nbsp;<span class="constructor">DEST</span>&nbsp;</code></pre>
    The <code class="code"><span class="constructor">DEST</span></code> argument must be a directory if there is more than 
    one <code class="code"><span class="constructor">SOURCE</span></code>. This constraint is too complex to be expressed by the
    combinators of <a href="Cmdliner.Arg.html"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span></code></a>. Hence we just give it the <a href="Cmdliner.Arg.html#VALstring"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.string</code></a> type
    and verify the constraint at the beginning of the <code class="code">cp</code>
    implementation. If unsatisfied we return an <code class="code"><span class="keywordsign">`</span><span class="constructor">Error</span></code> and
    by using <a href="Cmdliner.Term.html#VALret"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.ret</code></a> on the lifted result <code class="code">cp_t</code> of <code class="code">cp</code>, 
    <code class="code"><span class="constructor">Cmdliner</span></code> handles the error reporting.
<pre class="codepre"><code class="code"><span class="comment">(*&nbsp;Implementation,&nbsp;we&nbsp;check&nbsp;the&nbsp;dest&nbsp;argument&nbsp;and&nbsp;print&nbsp;the&nbsp;args&nbsp;*)</span><br>
<br>
<span class="keyword">let</span>&nbsp;cp&nbsp;verbose&nbsp;recurse&nbsp;force&nbsp;srcs&nbsp;dest&nbsp;=<br>
&nbsp;&nbsp;<span class="keyword">if</span>&nbsp;<span class="constructor">List</span>.length&nbsp;srcs&nbsp;&gt;&nbsp;1&nbsp;<span class="keywordsign">&amp;&amp;</span>&nbsp;<br>
&nbsp;&nbsp;(not&nbsp;(<span class="constructor">Sys</span>.file_exists&nbsp;dest)&nbsp;<span class="keywordsign">||</span>&nbsp;not&nbsp;(<span class="constructor">Sys</span>.is_directory&nbsp;dest))&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">then</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;(<span class="keyword">false</span>,&nbsp;dest&nbsp;^&nbsp;<span class="string">"&nbsp;is&nbsp;not&nbsp;a&nbsp;directory"</span>)&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">else</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;(<span class="constructor">Printf</span>.printf&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="string">"verbose&nbsp;=&nbsp;%b\nrecurse&nbsp;=&nbsp;%b\nforce&nbsp;=&nbsp;%b\nsrcs&nbsp;=&nbsp;%s\ndest&nbsp;=&nbsp;%s\n"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;verbose&nbsp;recurse&nbsp;force&nbsp;(<span class="constructor">String</span>.concat&nbsp;<span class="string">",&nbsp;"</span>&nbsp;srcs)&nbsp;dest)<br>
<br>
<span class="comment">(*&nbsp;Command&nbsp;line&nbsp;interface&nbsp;*)</span><br>
<br>
<span class="keyword">open</span>&nbsp;<span class="constructor">Cmdliner</span>;;<br>
<br>
<span class="keyword">let</span>&nbsp;verbose&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Print&nbsp;file&nbsp;names&nbsp;as&nbsp;they&nbsp;are&nbsp;copied."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"v"</span>;&nbsp;<span class="string">"verbose"</span>]&nbsp;~doc)&nbsp;<br>
<br>
<span class="keyword">let</span>&nbsp;recurse&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Copy&nbsp;directories&nbsp;recursively."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"r"</span>;&nbsp;<span class="string">"R"</span>;&nbsp;<span class="string">"recursive"</span>]&nbsp;~doc)<br>
<br>
<span class="keyword">let</span>&nbsp;force&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"If&nbsp;a&nbsp;destination&nbsp;file&nbsp;cannot&nbsp;be&nbsp;opened,&nbsp;remove&nbsp;it&nbsp;and&nbsp;try&nbsp;again."</span><span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"f"</span>;&nbsp;<span class="string">"force"</span>]&nbsp;~doc)<br>
<br>
<span class="keyword">let</span>&nbsp;srcs&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Source&nbsp;file(s)&nbsp;to&nbsp;copy."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(non_empty&nbsp;<span class="keywordsign">&amp;</span>&nbsp;pos_left&nbsp;~rev:<span class="keyword">true</span>&nbsp;0&nbsp;file&nbsp;[]&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"SOURCE"</span>&nbsp;~doc)&nbsp;<br>
<br>
<span class="keyword">let</span>&nbsp;dest&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Destination&nbsp;of&nbsp;the&nbsp;copy.&nbsp;Must&nbsp;be&nbsp;a&nbsp;directory&nbsp;if&nbsp;there&nbsp;is&nbsp;more&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;than&nbsp;one&nbsp;$(i,SOURCE)."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(required&nbsp;<span class="keywordsign">&amp;</span>&nbsp;pos&nbsp;~rev:<span class="keyword">true</span>&nbsp;0&nbsp;(some&nbsp;string)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"DEST"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~doc)<br>
<br>
<span class="keyword">let</span>&nbsp;cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"copy&nbsp;files"</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;[<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"BUGS"</span>;&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Email&nbsp;them&nbsp;to&nbsp;&lt;hehey&nbsp;at&nbsp;example.org&gt;."</span>;&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"SEE&nbsp;ALSO"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(b,mv)(1),&nbsp;$(b,scp)(1),&nbsp;$(b,umask)(2),&nbsp;$(b,symlink)(7)"</span>&nbsp;]<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(ret&nbsp;(pure&nbsp;cp&nbsp;$&nbsp;verbose&nbsp;$&nbsp;recurse&nbsp;$&nbsp;force&nbsp;$&nbsp;srcs&nbsp;$&nbsp;dest)),&nbsp;<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"cp"</span>&nbsp;~version:<span class="string">"1.6.1"</span>&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval&nbsp;cmd&nbsp;<span class="keyword">with</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0<br>
</code></pre>
<p>

<h2 id="extail">A <code class="code">tail</code> command</h2>
<p>

We define the command line interface of a <code class="code">tail</code> command with the 
synopsis:
<pre class="codepre"><code class="code">tail&nbsp;[<span class="constructor">OPTION</span>]...&nbsp;[<span class="constructor">FILE</span>]...</code></pre>
<p>

The <code class="code">--lines</code> option whose value specifies the number of last lines to
print has a special syntax where a <code class="code">+</code> prefix indicates to start
printing from that line number. In the program this is represented by
the <code class="code">loc</code> type. We define a custom <code class="code">loc</code> <a href="Cmdliner.Arg.html#argconv">argument converter</a> 
for this option.
<p>

The <code class="code">--follow</code> option has an optional enumerated value. The argument
converter <code class="code">follow</code>, created with <a href="Cmdliner.Arg.html#VALenum"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.enum</code></a> parses the option value
into the enumeration. By using <a href="Cmdliner.Arg.html#VALsome"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.some</code></a> and the <code class="code">~vopt</code> argument of
<a href="Cmdliner.Arg.html#VALopt"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.opt</code></a>, the term corresponding to the option <code class="code">--follow</code> evaluates to
<code class="code"><span class="constructor">None</span></code> if <code class="code">--follow</code> is absent from the command line, to <code class="code"><span class="constructor">Some</span> <span class="constructor">Descriptor</span></code>
if present but without a value and to <code class="code"><span class="constructor">Some</span> v</code> if present with a value
<code class="code">v</code> specified.
<p>

<pre class="codepre"><code class="code"><span class="comment">(*&nbsp;Implementation&nbsp;of&nbsp;the&nbsp;command,&nbsp;we&nbsp;just&nbsp;print&nbsp;the&nbsp;args.&nbsp;*)</span><br>
<br>
<span class="keyword">type</span>&nbsp;loc&nbsp;=&nbsp;bool&nbsp;*&nbsp;int<br>
<span class="keyword">type</span>&nbsp;verb&nbsp;=&nbsp;<span class="constructor">Verbose</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Quiet</span>&nbsp;<br>
<span class="keyword">type</span>&nbsp;follow&nbsp;=&nbsp;<span class="constructor">Name</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Descriptor</span><br>
<br>
<span class="keyword">let</span>&nbsp;str&nbsp;=&nbsp;<span class="constructor">Printf</span>.sprintf&nbsp;<br>
<span class="keyword">let</span>&nbsp;opt_str&nbsp;sv&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"None"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Some</span>&nbsp;v&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;str&nbsp;<span class="string">"Some(%s)"</span>&nbsp;(sv&nbsp;v)<br>
<span class="keyword">let</span>&nbsp;loc_str&nbsp;(rev,&nbsp;k)&nbsp;=&nbsp;<span class="keyword">if</span>&nbsp;rev&nbsp;<span class="keyword">then</span>&nbsp;str&nbsp;<span class="string">"%d"</span>&nbsp;k&nbsp;<span class="keyword">else</span>&nbsp;str&nbsp;<span class="string">"+%d"</span>&nbsp;k<br>
<span class="keyword">let</span>&nbsp;follow_str&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<span class="constructor">Name</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"name"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Descriptor</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"descriptor"</span><br>
<span class="keyword">let</span>&nbsp;verb_str&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<span class="constructor">Verbose</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"verbose"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Quiet</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"quiet"</span><br>
<br>
<span class="keyword">let</span>&nbsp;tail&nbsp;lines&nbsp;follow&nbsp;verb&nbsp;pid&nbsp;files&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="constructor">Printf</span>.printf&nbsp;<span class="string">"lines&nbsp;=&nbsp;%s\nfollow&nbsp;=&nbsp;%s\nverb&nbsp;=&nbsp;%s\npid&nbsp;=&nbsp;%s\nfiles&nbsp;=&nbsp;%s\n"</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;(loc_str&nbsp;lines)&nbsp;(opt_str&nbsp;follow_str&nbsp;follow)&nbsp;(verb_str&nbsp;verb)&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;(opt_str&nbsp;string_of_int&nbsp;pid)&nbsp;(<span class="constructor">String</span>.concat&nbsp;<span class="string">",&nbsp;"</span>&nbsp;files)<br>
<br>
<span class="comment">(*&nbsp;Command&nbsp;line&nbsp;interface&nbsp;*)</span><br>
<br>
<span class="keyword">open</span>&nbsp;<span class="constructor">Cmdliner</span>;;<br>
<br>
<span class="keyword">let</span>&nbsp;lines&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;loc&nbsp;=<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;parse&nbsp;s&nbsp;=&nbsp;<span class="keyword">try</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">if</span>&nbsp;s&nbsp;&lt;&gt;&nbsp;<span class="string">""</span>&nbsp;<span class="keywordsign">&amp;&amp;</span>&nbsp;s.[0]&nbsp;&lt;&gt;&nbsp;<span class="string">'+'</span>&nbsp;<span class="keyword">then</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;(<span class="keyword">true</span>,&nbsp;int_of_string&nbsp;s)&nbsp;<span class="keyword">else</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;(<span class="keyword">false</span>,&nbsp;int_of_string&nbsp;(<span class="constructor">String</span>.sub&nbsp;s&nbsp;1&nbsp;(<span class="constructor">String</span>.length&nbsp;s&nbsp;-&nbsp;1)))&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">with</span>&nbsp;<span class="constructor">Failure</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;<span class="string">"unable&nbsp;to&nbsp;parse&nbsp;integer"</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;parse,&nbsp;<span class="keyword">fun</span>&nbsp;ppf&nbsp;p&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">Format</span>.fprintf&nbsp;ppf&nbsp;<span class="string">"%s"</span>&nbsp;(loc_str&nbsp;p)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;loc&nbsp;(<span class="keyword">true</span>,&nbsp;10)&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"n"</span>;&nbsp;<span class="string">"lines"</span>]&nbsp;~docv:<span class="string">"N"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~doc:<span class="string">"Output&nbsp;the&nbsp;last&nbsp;$(docv)&nbsp;lines&nbsp;or&nbsp;use&nbsp;$(i,+)$(docv)&nbsp;to&nbsp;start&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;output&nbsp;after&nbsp;the&nbsp;$(i,N)-1th&nbsp;line."</span>)&nbsp;<br>
<span class="keyword">let</span>&nbsp;follow&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Output&nbsp;appended&nbsp;data&nbsp;as&nbsp;the&nbsp;file&nbsp;grows.&nbsp;$(docv)&nbsp;specifies&nbsp;how&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;file&nbsp;should&nbsp;be&nbsp;tracked,&nbsp;by&nbsp;its&nbsp;`name'&nbsp;or&nbsp;by&nbsp;its&nbsp;`descriptor'."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;follow&nbsp;=&nbsp;<span class="constructor">Arg</span>.enum&nbsp;[<span class="string">"name"</span>,&nbsp;<span class="constructor">Name</span>;&nbsp;<span class="string">"descriptor"</span>,&nbsp;<span class="constructor">Descriptor</span>]&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;(some&nbsp;follow)&nbsp;~vopt:(<span class="constructor">Some</span>&nbsp;<span class="constructor">Descriptor</span>)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;info&nbsp;[<span class="string">"f"</span>;&nbsp;<span class="string">"follow"</span>]&nbsp;~docv:<span class="string">"ID"</span>&nbsp;~doc)&nbsp;<br>
<br>
<span class="keyword">let</span>&nbsp;verb&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Never&nbsp;output&nbsp;headers&nbsp;giving&nbsp;file&nbsp;names."</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;quiet&nbsp;=&nbsp;<span class="constructor">Quiet</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"q"</span>;&nbsp;<span class="string">"quiet"</span>;&nbsp;<span class="string">"silent"</span>]&nbsp;~doc&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Always&nbsp;output&nbsp;headers&nbsp;giving&nbsp;file&nbsp;names."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;verbose&nbsp;=&nbsp;<span class="constructor">Verbose</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"v"</span>;&nbsp;<span class="string">"verbose"</span>]&nbsp;~doc&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(last&nbsp;<span class="keywordsign">&amp;</span>&nbsp;vflag_all&nbsp;[<span class="constructor">Quiet</span>]&nbsp;[quiet;&nbsp;verbose])<br>
<br>
<span class="keyword">let</span>&nbsp;pid&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"With&nbsp;-f,&nbsp;terminate&nbsp;after&nbsp;process&nbsp;$(docv)&nbsp;dies."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;(some&nbsp;int)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"pid"</span>]&nbsp;~docv:<span class="string">"PID"</span>&nbsp;~doc)<br>
<br>
<span class="keyword">let</span>&nbsp;files&nbsp;=&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;(pos_all&nbsp;non_dir_file&nbsp;[])&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"FILE"</span>)<br>
<br>
<span class="keyword">let</span>&nbsp;cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"display&nbsp;the&nbsp;last&nbsp;part&nbsp;of&nbsp;a&nbsp;file"</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;[<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"DESCRIPTION"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(tname)&nbsp;prints&nbsp;the&nbsp;last&nbsp;lines&nbsp;of&nbsp;each&nbsp;$(i,FILE)&nbsp;to&nbsp;standard&nbsp;output.&nbsp;If<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;no&nbsp;file&nbsp;is&nbsp;specified&nbsp;reads&nbsp;standard&nbsp;input.&nbsp;The&nbsp;number&nbsp;of&nbsp;printed<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;lines&nbsp;can&nbsp;be&nbsp;&nbsp;specified&nbsp;with&nbsp;the&nbsp;$(b,-n)&nbsp;option."</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"BUGS"</span>;&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Report&nbsp;them&nbsp;to&nbsp;&lt;hehey&nbsp;at&nbsp;example.org&gt;."</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"SEE&nbsp;ALSO"</span>;&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"$(b,cat)(1),&nbsp;$(b,head)(1)"</span>&nbsp;]<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(pure&nbsp;tail&nbsp;$&nbsp;lines&nbsp;$&nbsp;follow&nbsp;$&nbsp;verb&nbsp;$&nbsp;pid&nbsp;$&nbsp;files),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"tail"</span>&nbsp;~version:<span class="string">"1.6.1"</span>&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval&nbsp;cmd&nbsp;<span class="keyword">with</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0<br>
</code></pre>
<p>

<h2 id="exdarcs">A <code class="code">darcs</code> command</h2>
<p>

We define the command line interface of a <code class="code">darcs</code> command with the synopsis:
<pre class="codepre"><code class="code">darcs&nbsp;[<span class="constructor">COMMAND</span>]&nbsp;...</code></pre>
<p>

The <code class="code">--debug</code>, <code class="code">-q</code>, <code class="code">-v</code> and <code class="code">--prehook</code> options are available in
each command.  To avoid having to pass them individually to each
command we gather them in a record of type <code class="code">copts</code>. By lifting the
record constructor <code class="code">copts</code> into the term <code class="code">copts_t</code> we now have a term
that we can pass to the commands to stand for an argument of type
<code class="code">copts</code>. These options are documented in a section called <code class="code"><span class="constructor">COMMON</span>
<span class="constructor">OPTIONS</span></code>, since we also want to put <code class="code">--help</code> and <code class="code">--version</code> in this
section, the term information of commands makes a judicious use of the
<code class="code">sdocs</code> parameter of <a href="Cmdliner.Term.html#VALinfo"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.info</code></a>.
<p>

The <code class="code">help</code> command shows help about commands or other topics. The help
shown for commands is generated by <code class="code"><span class="constructor">Cmdliner</span></code> by making an approriate
use of <a href="Cmdliner.Term.html#VALret"><code class="code"><span class="constructor">Cmdliner</span>.<span class="constructor">Term</span>.ret</code></a> on the lifted <code class="code">help</code> function.
<p>

If the program is invoked without a command we just want to show the
help of the program as printed by <code class="code"><span class="constructor">Cmdliner</span></code> with <code class="code">--help</code>. This is
done by the <code class="code">no_cmd</code> term.
<p>

<pre class="codepre"><code class="code"><span class="comment">(*&nbsp;Implementations,&nbsp;just&nbsp;print&nbsp;the&nbsp;args.&nbsp;*)</span><br>
<br>
<span class="keyword">type</span>&nbsp;verb&nbsp;=&nbsp;<span class="constructor">Normal</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Quiet</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Verbose</span><br>
<span class="keyword">type</span>&nbsp;copts&nbsp;=&nbsp;{&nbsp;debug&nbsp;:&nbsp;bool;&nbsp;verb&nbsp;:&nbsp;verb;&nbsp;prehook&nbsp;:&nbsp;string&nbsp;option&nbsp;}<br>
<br>
<span class="keyword">let</span>&nbsp;str&nbsp;=&nbsp;<span class="constructor">Printf</span>.sprintf&nbsp;<br>
<span class="keyword">let</span>&nbsp;opt_str&nbsp;sv&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"None"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Some</span>&nbsp;v&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;str&nbsp;<span class="string">"Some(%s)"</span>&nbsp;(sv&nbsp;v)<br>
<span class="keyword">let</span>&nbsp;opt_str_str&nbsp;=&nbsp;opt_str&nbsp;(<span class="keyword">fun</span>&nbsp;s&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;s)<br>
<span class="keyword">let</span>&nbsp;verb_str&nbsp;=&nbsp;<span class="keyword">function</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Normal</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"normal"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Quiet</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"quiet"</span>&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="constructor">Verbose</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="string">"verbose"</span><br>
<br>
<span class="keyword">let</span>&nbsp;pr_copts&nbsp;oc&nbsp;copts&nbsp;=&nbsp;<span class="constructor">Printf</span>.fprintf&nbsp;oc&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="string">"debug&nbsp;=&nbsp;%b\nverbosity&nbsp;=&nbsp;%s\nprehook&nbsp;=&nbsp;%s\n"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;copts.debug&nbsp;(verb_str&nbsp;copts.verb)&nbsp;(opt_str_str&nbsp;copts.prehook)<br>
<br>
<span class="keyword">let</span>&nbsp;initialize&nbsp;copts&nbsp;repodir&nbsp;=&nbsp;<span class="constructor">Printf</span>.printf<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="string">"%arepodir&nbsp;=&nbsp;%s\n"</span>&nbsp;pr_copts&nbsp;copts&nbsp;repodir<br>
<br>
<span class="keyword">let</span>&nbsp;record&nbsp;copts&nbsp;name&nbsp;email&nbsp;all&nbsp;ask_deps&nbsp;files&nbsp;=&nbsp;<span class="constructor">Printf</span>.printf<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="string">"%aname&nbsp;=&nbsp;%s\nemail&nbsp;=&nbsp;%s\nall&nbsp;=&nbsp;%b\nask-deps&nbsp;=&nbsp;%b\nfiles&nbsp;=&nbsp;%s\n"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;pr_copts&nbsp;copts&nbsp;(opt_str_str&nbsp;name)&nbsp;(opt_str_str&nbsp;email)&nbsp;all&nbsp;ask_deps&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;(<span class="constructor">String</span>.concat&nbsp;<span class="string">",&nbsp;"</span>&nbsp;files)<br>
<br>
<span class="keyword">let</span>&nbsp;help&nbsp;copts&nbsp;man_format&nbsp;cmds&nbsp;topic&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;topic&nbsp;<span class="keyword">with</span><br>
<span class="keywordsign">|</span>&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Help</span>&nbsp;(<span class="keywordsign">`</span><span class="constructor">Pager</span>,&nbsp;<span class="constructor">None</span>)&nbsp;<span class="comment">(*&nbsp;help&nbsp;about&nbsp;the&nbsp;program.&nbsp;*)</span><br>
<span class="keywordsign">|</span>&nbsp;<span class="constructor">Some</span>&nbsp;topic&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;topics&nbsp;=&nbsp;<span class="string">"topics"</span>&nbsp;::&nbsp;<span class="string">"patterns"</span>&nbsp;::&nbsp;<span class="string">"environment"</span>&nbsp;::&nbsp;cmds&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;conv,&nbsp;_&nbsp;=&nbsp;<span class="constructor">Cmdliner</span>.<span class="constructor">Arg</span>.enum&nbsp;(<span class="constructor">List</span>.rev_map&nbsp;(<span class="keyword">fun</span>&nbsp;s&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;(s,&nbsp;s))&nbsp;topics)&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">match</span>&nbsp;conv&nbsp;topic&nbsp;<span class="keyword">with</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;e&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;(<span class="keyword">false</span>,&nbsp;e)<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;t&nbsp;<span class="keyword">when</span>&nbsp;t&nbsp;=&nbsp;<span class="string">"topics"</span>&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="constructor">List</span>.iter&nbsp;print_endline&nbsp;topics;&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;()<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;t&nbsp;<span class="keyword">when</span>&nbsp;<span class="constructor">List</span>.mem&nbsp;t&nbsp;cmds&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Help</span>&nbsp;(man_format,&nbsp;<span class="constructor">Some</span>&nbsp;t)<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;page&nbsp;=&nbsp;(topic,&nbsp;7,&nbsp;<span class="string">""</span>,&nbsp;<span class="string">""</span>,&nbsp;<span class="string">""</span>),&nbsp;[<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;topic;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Say&nbsp;something"</span>;]&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">Ok</span>&nbsp;(<span class="constructor">Cmdliner</span>.<span class="constructor">Manpage</span>.print&nbsp;man_format&nbsp;<span class="constructor">Format</span>.std_formatter&nbsp;page)<br>
<br>
<span class="keyword">open</span>&nbsp;<span class="constructor">Cmdliner</span>;;<br>
<br>
<span class="comment">(*&nbsp;Help&nbsp;sections&nbsp;common&nbsp;to&nbsp;all&nbsp;commands&nbsp;*)</span><br>
<br>
<span class="keyword">let</span>&nbsp;copts_sect&nbsp;=&nbsp;<span class="string">"COMMON&nbsp;OPTIONS"</span><br>
<span class="keyword">let</span>&nbsp;help_secs&nbsp;=&nbsp;[&nbsp;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;copts_sect;&nbsp;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"These&nbsp;options&nbsp;are&nbsp;common&nbsp;to&nbsp;all&nbsp;commands."</span>;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"MORE&nbsp;HELP"</span>;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Use&nbsp;`$(mname)&nbsp;$(i,COMMAND)&nbsp;--help'&nbsp;for&nbsp;help&nbsp;on&nbsp;a&nbsp;single&nbsp;command."</span>;<span class="keywordsign">`</span><span class="constructor">Noblank</span>;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Use&nbsp;`$(mname)&nbsp;help&nbsp;patterns'&nbsp;for&nbsp;help&nbsp;on&nbsp;patch&nbsp;matching."</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">Noblank</span>;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Use&nbsp;`$(mname)&nbsp;help&nbsp;environment'&nbsp;for&nbsp;help&nbsp;on&nbsp;environment&nbsp;variables."</span>;<br>
&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"BUGS"</span>;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Check&nbsp;bug&nbsp;reports&nbsp;at&nbsp;http://bugs.example.org."</span>;]<br>
<br>
<span class="comment">(*&nbsp;Options&nbsp;common&nbsp;to&nbsp;all&nbsp;commands&nbsp;*)</span><br>
<br>
<span class="keyword">let</span>&nbsp;copts&nbsp;debug&nbsp;verb&nbsp;prehook&nbsp;=&nbsp;{&nbsp;debug;&nbsp;verb;&nbsp;prehook&nbsp;}<br>
<span class="keyword">let</span>&nbsp;copts_t&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;docs&nbsp;=&nbsp;copts_sect&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;debug&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Give&nbsp;only&nbsp;debug&nbsp;output."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"debug"</span>]&nbsp;~docs&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;verb&nbsp;=<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Suppress&nbsp;informational&nbsp;output."</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;quiet&nbsp;=&nbsp;<span class="constructor">Quiet</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"q"</span>;&nbsp;<span class="string">"quiet"</span>]&nbsp;~docs&nbsp;~doc&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Give&nbsp;verbose&nbsp;output."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;verbose&nbsp;=&nbsp;<span class="constructor">Verbose</span>,&nbsp;<span class="constructor">Arg</span>.info&nbsp;[<span class="string">"v"</span>;&nbsp;<span class="string">"verbose"</span>]&nbsp;~docs&nbsp;~doc&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(last&nbsp;<span class="keywordsign">&amp;</span>&nbsp;vflag_all&nbsp;[<span class="constructor">Normal</span>]&nbsp;[quiet;&nbsp;verbose])&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;prehook&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Specify&nbsp;command&nbsp;to&nbsp;run&nbsp;before&nbsp;this&nbsp;$(mname)&nbsp;command."</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;(some&nbsp;string)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"prehook"</span>]&nbsp;~docs&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(pure&nbsp;copts&nbsp;$&nbsp;debug&nbsp;$&nbsp;verb&nbsp;$&nbsp;prehook)<br>
&nbsp;&nbsp;&nbsp;&nbsp;<br>
<span class="comment">(*&nbsp;Commands&nbsp;*)</span><br>
<br>
<span class="keyword">let</span>&nbsp;initialize_cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;repodir&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Run&nbsp;the&nbsp;program&nbsp;in&nbsp;repository&nbsp;directory&nbsp;$(docv)."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;file&nbsp;<span class="constructor">Filename</span>.current_dir_name&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"repodir"</span>]<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~docv:<span class="string">"DIR"</span>&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"make&nbsp;the&nbsp;current&nbsp;directory&nbsp;a&nbsp;repository"</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;[<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"DESCRIPTION"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Turns&nbsp;the&nbsp;current&nbsp;directory&nbsp;into&nbsp;a&nbsp;Darcs&nbsp;repository.&nbsp;Any<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;existing&nbsp;files&nbsp;and&nbsp;subdirectories&nbsp;become&nbsp;..."</span>]&nbsp;@&nbsp;help_secs<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(pure&nbsp;initialize&nbsp;$&nbsp;copts_t&nbsp;$&nbsp;repodir),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"initialize"</span>&nbsp;~sdocs:copts_sect&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;record_cmd&nbsp;=<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;pname&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Name&nbsp;of&nbsp;the&nbsp;patch."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;(some&nbsp;string)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"m"</span>;&nbsp;<span class="string">"patch-name"</span>]&nbsp;~docv:<span class="string">"NAME"</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;author&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Specifies&nbsp;the&nbsp;author's&nbsp;identity."</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;opt&nbsp;(some&nbsp;string)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"A"</span>;&nbsp;<span class="string">"author"</span>]&nbsp;~docv:<span class="string">"EMAIL"</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;all&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Answer&nbsp;yes&nbsp;to&nbsp;all&nbsp;patches."</span>&nbsp;<span class="keyword">in</span>&nbsp;&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"a"</span>;&nbsp;<span class="string">"all"</span>]&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;ask_deps&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"Ask&nbsp;for&nbsp;extra&nbsp;dependencies."</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;flag&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[<span class="string">"ask-deps"</span>]&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;files&nbsp;=&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;(pos_all&nbsp;file)&nbsp;[]&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"FILE&nbsp;or&nbsp;DIR"</span>)&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"create&nbsp;a&nbsp;patch&nbsp;from&nbsp;unrecorded&nbsp;changes"</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;[<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"DESCRIPTION"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Creates&nbsp;a&nbsp;patch&nbsp;from&nbsp;changes&nbsp;in&nbsp;the&nbsp;working&nbsp;tree.&nbsp;If&nbsp;you&nbsp;specify&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a&nbsp;set&nbsp;of&nbsp;files&nbsp;..."</span>]&nbsp;@&nbsp;help_secs<br>
&nbsp;&nbsp;<span class="keyword">in</span>&nbsp;&nbsp;&nbsp;&nbsp;<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(pure&nbsp;record&nbsp;$&nbsp;copts_t&nbsp;$&nbsp;pname&nbsp;$&nbsp;author&nbsp;$&nbsp;all&nbsp;$&nbsp;ask_deps&nbsp;$&nbsp;files),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"record"</span>&nbsp;~doc&nbsp;~sdocs:copts_sect&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;help_cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;topic&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"The&nbsp;topic&nbsp;to&nbsp;get&nbsp;help&nbsp;on.&nbsp;`topics'&nbsp;lists&nbsp;the&nbsp;topics."</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="constructor">Arg</span>.(value&nbsp;<span class="keywordsign">&amp;</span>&nbsp;pos&nbsp;0&nbsp;(some&nbsp;string)&nbsp;<span class="constructor">None</span>&nbsp;<span class="keywordsign">&amp;</span>&nbsp;info&nbsp;[]&nbsp;~docv:<span class="string">"TOPIC"</span>&nbsp;~doc)<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"display&nbsp;help&nbsp;about&nbsp;darcs&nbsp;and&nbsp;darcs&nbsp;commands"</span>&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;[<span class="keywordsign">`</span><span class="constructor">S</span>&nbsp;<span class="string">"DESCRIPTION"</span>;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keywordsign">`</span><span class="constructor">P</span>&nbsp;<span class="string">"Prints&nbsp;help&nbsp;about&nbsp;darcs&nbsp;commands&nbsp;and&nbsp;other&nbsp;subjects..."</span>]&nbsp;@&nbsp;help_secs<br>
&nbsp;&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(ret&nbsp;(pure&nbsp;help&nbsp;$&nbsp;copts_t&nbsp;$&nbsp;<span class="constructor">Term</span>.man_format&nbsp;$&nbsp;<span class="constructor">Term</span>.choice_names&nbsp;$topic)),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"help"</span>&nbsp;~doc&nbsp;~man<br>
<br>
<span class="keyword">let</span>&nbsp;default_cmd&nbsp;=&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;doc&nbsp;=&nbsp;<span class="string">"a&nbsp;revision&nbsp;control&nbsp;system"</span>&nbsp;<span class="keyword">in</span>&nbsp;<br>
&nbsp;&nbsp;<span class="keyword">let</span>&nbsp;man&nbsp;=&nbsp;help_secs&nbsp;<span class="keyword">in</span><br>
&nbsp;&nbsp;<span class="constructor">Term</span>.(ret&nbsp;(pure&nbsp;(<span class="keyword">fun</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Help</span>&nbsp;(<span class="keywordsign">`</span><span class="constructor">Pager</span>,&nbsp;<span class="constructor">None</span>))&nbsp;$&nbsp;copts_t)),<br>
&nbsp;&nbsp;<span class="constructor">Term</span>.info&nbsp;<span class="string">"darcs"</span>&nbsp;~version:<span class="string">"1.6.1"</span>&nbsp;~sdocs:copts_sect&nbsp;~doc&nbsp;~man<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br>
<span class="keyword">let</span>&nbsp;cmds&nbsp;=&nbsp;[initialize_cmd;&nbsp;record_cmd;&nbsp;help_cmd]<br>
<br>
<span class="keyword">let</span>&nbsp;()&nbsp;=&nbsp;<span class="keyword">match</span>&nbsp;<span class="constructor">Term</span>.eval_choice&nbsp;default_cmd&nbsp;cmds&nbsp;<span class="keyword">with</span>&nbsp;<br>
<span class="keywordsign">|</span>&nbsp;<span class="keywordsign">`</span><span class="constructor">Error</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;1&nbsp;<span class="keywordsign">|</span>&nbsp;_&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;exit&nbsp;0<br>
</code></pre><br>
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