1 files changed, 84 insertions, 0 deletions
diff --git a/clap/examples/18_builder_macro.rs b/clap/examples/18_builder_macro.rs
new file mode 100644
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+++ b/clap/examples/18_builder_macro.rs
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+#[macro_use]
+extern crate clap;
+
+// Note, there isn't a need for "use clap::{ ... };" Because the clap_app! macro uses
+// $crate:: internally
+
+fn main() {
+
+    // Validation example testing that a file exists
+    let file_exists = |path| {
+        if std::fs::metadata(path).is_ok() {
+            Ok(())
+        } else {
+            Err(String::from("File doesn't exist"))
+        }
+    };
+
+    // External module may contain this subcommand. If this exists in another module, a function is
+    // required to access it. Recommend `fn clap() -> Clap::SubCommand`.
+    let external_sub_command = clap_app!( @subcommand foo =>
+        (@arg bar: -b "Bar")
+    );
+
+    let matches = clap_app!(MyApp =>
+        (@setting SubcommandRequiredElseHelp)
+        (version: "1.0")
+        (author: "Alice")
+        (about: "Does awesome things")
+        (@arg config: -c --config <conf> #{1, 2} {file_exists} "Sets a custom config file")
+        (@arg proxyHostname: --("proxy-hostname") +takes_value "Sets the hostname of the proxy to use")
+        (@arg input: * "Input file")
+        (@group test =>
+            (@attributes +required)
+            (@arg output: "Sets an optional output file")
+            (@arg debug: -d ... "Turn debugging information on")
+        )
+        (subcommand: external_sub_command)
+        (@subcommand test =>
+            (about: "does testing things")
+            (version: "2.5")
+            (@arg list: -l "Lists test values")
+            (@arg test_req: -r requires[list] "Tests requirement for listing")
+            (@arg aaaa: --aaaa +takes_value {
+                    |a| if a.contains('a') {
+                        Ok(())
+                    } else {
+                        Err(String::from("string does not contain at least one a"))
+                    }
+                } "Test if the argument contains an a")
+        )
+    ).get_matches();
+
+    // You can check the value provided by positional arguments, or option arguments
+    if let Some(o) = matches.value_of("output") {
+        println!("Value for output: {}", o);
+    }
+
+    if let Some(c) = matches.value_of("config") {
+        println!("Value for config: {}", c);
+    }
+
+    // You can see how many times a particular flag or argument occurred
+    // Note, only flags can have multiple occurrences
+    match matches.occurrences_of("debug") {
+        0 => println!("Debug mode is off"),
+        1 => println!("Debug mode is kind of on"),
+        2 => println!("Debug mode is on"),
+        3 | _ => println!("Don't be crazy"),
+    }
+
+    // You can check for the existence of subcommands, and if found use their
+    // matches just as you would the top level app
+    if let Some(matches) = matches.subcommand_matches("test") {
+        // "$ myapp test" was run
+        if matches.is_present("list") {
+            // "$ myapp test -l" was run
+            println!("Printing testing lists...");
+        } else {
+            println!("Not printing testing lists...");
+        }
+    }
+
+    // Continued program logic goes here...
+}