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        <ol class="chapter"><li><a href="../intro.zh.html"><strong aria-hidden="true">1.</strong> 目录表</a></li><li><a href="../about.zh.html"><strong aria-hidden="true">2.</strong> 关于</a></li><li><a href="../algorithms.zh.html"><strong aria-hidden="true">3.</strong> 算法</a></li><li><ol class="section"><li><a href="../algorithms/randomness.zh.html"><strong aria-hidden="true">3.1.</strong> 生成随机值</a></li><li><a href="../algorithms/sorting.zh.html"><strong aria-hidden="true">3.2.</strong> 排序向量</a></li></ol></li><li><a href="../cli.zh.html"><strong aria-hidden="true">4.</strong> 命令行</a></li><li><ol class="section"><li><a href="../cli/arguments.zh.html" class="active"><strong aria-hidden="true">4.1.</strong> 参数解析</a></li><li><a href="../cli/ansi_terminal.zh.html"><strong aria-hidden="true">4.2.</strong> ANSI 终端</a></li></ol></li><li><a href="../compression.zh.html"><strong aria-hidden="true">5.</strong> 压缩</a></li><li><ol class="section"><li><a href="../compression/tar.zh.html"><strong aria-hidden="true">5.1.</strong> 与 Tarballs 合作</a></li></ol></li><li><a href="../concurrency.zh.html"><strong aria-hidden="true">6.</strong> 并发性</a></li><li><ol class="section"><li><a href="../concurrency/threads.zh.html"><strong aria-hidden="true">6.1.</strong> 显式线程</a></li><li><a href="../concurrency/parallel.zh.html"><strong aria-hidden="true">6.2.</strong> 数据并行性</a></li></ol></li><li><a href="../cryptography.zh.html"><strong aria-hidden="true">7.</strong> 密码学</a></li><li><ol class="section"><li><a href="../cryptography/hashing.zh.html"><strong aria-hidden="true">7.1.</strong> 哈希</a></li><li><a href="../cryptography/encryption.zh.html"><strong aria-hidden="true">7.2.</strong> 加密</a></li></ol></li><li><a href="../data_structures.zh.html"><strong aria-hidden="true">8.</strong> 数据结构</a></li><li><ol class="section"><li><a href="../data_structures/bitfield.zh.html"><strong aria-hidden="true">8.1.</strong> 位字段</a></li></ol></li><li><a href="../database.zh.html"><strong 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                    <a class="header" href="#拍手clap基本" id="拍手clap基本"><h1>拍手(clap)基本</h1></a>
<a class="header" href="#解析命令行参数" id="解析命令行参数"><h2>解析命令行参数</h2></a>
<p><a href="https://docs.rs/clap/"><img src="https://badge-cache.kominick.com/crates/v/clap.svg?label=clap" alt="clap-badge" /></a> <a href="https://crates.io/categories/command-line-interface"><img src="https://badge-cache.kominick.com/badge/command_line--x.svg?style=social" alt="cat-command-line-badge" /></a></p>
<p>通过使用<code>clap</code>的构建样式，该应用程序描述了其命令行界面的结构。该<a href="https://docs.rs/clap/">文档</a>提供了，另外两种可能的方法，去实例化应用程序。</p>
<p>在构建样式中，<code>with_name</code>是唯一标识符，而<code>value_of</code>则用于检索传递的值。该<code>short</code>和<code>long</code>选项控制用户将要键入的标志; <code>short</code>标志<code>-f</code>和<code>long</code>标志<code>--file</code>是同个标志。</p>
<pre><pre class="playpen"><code class="language-rust">extern crate clap;

use clap::{Arg, App};

fn main() {
    let matches = App::new(&quot;My Test Program&quot;)
        .version(&quot;0.1.0&quot;)
        .author(&quot;Hackerman Jones &lt;hckrmnjones@hack.gov&gt;&quot;)
        .about(&quot;Teaches argument parsing&quot;)
        .arg(Arg::with_name(&quot;file&quot;)
                 .short(&quot;f&quot;)
                 .long(&quot;file&quot;)
                 .takes_value(true)
                 .help(&quot;A cool file&quot;))
        .arg(Arg::with_name(&quot;num&quot;)
                 .short(&quot;n&quot;)
                 .long(&quot;number&quot;)
                 .takes_value(true)
                 .help(&quot;Five less than your favorite number&quot;))
        .get_matches();

    let myfile = matches.value_of(&quot;file&quot;).unwrap_or(&quot;input.txt&quot;);
    println!(&quot;The file passed is: {}&quot;, myfile);

    let num_str = matches.value_of(&quot;num&quot;);
    match num_str {
        None =&gt; println!(&quot;No idea what your favorite number is.&quot;),
        Some(s) =&gt; {
            match s.parse::&lt;i32&gt;() {
                Ok(n) =&gt; println!(&quot;Your favorite number must be {}.&quot;, n + 5),
                Err(_) =&gt; println!(&quot;That's not a number! {}&quot;, s),
            }
        }
    }
}
</code></pre></pre>
<p><code>help</code>信息，由<code>clap</code>生成。该示例应用程序的用法，如下所示。</p>
<pre><code class="language-bash">My Test Program 0.1.0
Hackerman Jones &lt;hckrmnjones@hack.gov&gt;
Teaches argument parsing

USAGE:
    testing [OPTIONS]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
    -f, --file &lt;file&gt;     A cool file
    -n, --number &lt;num&gt;    Five less than your favorite number
</code></pre>
<p>我们可以通过运行如下命令，来测试应用程序。</p>
<pre><code>$ cargo run -- -f myfile.txt -n 251
</code></pre>
<p>输出是：</p>
<pre><code>The file passed is: myfile.txt
Your favorite number must be 256.
</code></pre>
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