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diff --git a/clap/examples/13a_enum_values_automatic.rs b/clap/examples/13a_enum_values_automatic.rs
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+// You can use clap's value_t! macro with a custom enum by implementing the std::str::FromStr
+// trait which is very straight forward. There are three ways to do this, for simple enums
+// meaning those that don't require 'pub' or any '#[derive()]' directives you can use clap's
+// simple_enum! macro. For those that require 'pub' or any '#[derive()]'s you can use clap's
+// arg_enum! macro. The third way is to implement std::str::FromStr manually.
+//
+// In most circumstances using either simple_enum! or arg_enum! is fine.
+//
+// In the following example we will create two enums using macros, assign a positional argument
+// that accepts only one of those values, and use clap to parse the argument.
+
+// Add clap like normal
+#[macro_use]
+extern crate clap;
+
+use clap::{App, Arg};
+
+// Using arg_enum! is more like traditional enum declarations
+//
+// **NOTE:** Only bare variants are supported
+arg_enum!{
+    #[derive(Debug)]
+    pub enum Oof {
+        Rab,
+        Zab,
+        Xuq
+    }
+}
+
+arg_enum!{
+    #[derive(Debug)]
+    enum Foo {
+        Bar,
+        Baz,
+        Qux
+    }
+}
+
+fn main() {
+    // Create the application like normal
+    let enum_vals = ["fast", "slow"];
+    let m = App::new("myapp")
+                    // Use a single positional argument that is required
+                    .arg(Arg::from_usage("<foo> 'The Foo to use'")
+                        .possible_values(&Foo::variants()))
+                    .arg(Arg::from_usage("<speed> 'The speed to use'")
+                            // You can define a list of possible values if you want the values to be
+                            // displayed in the help information. Whether you use possible_values() or
+                            // not, the valid values will ALWAYS be displayed on a failed parse.
+                            .possible_values(&enum_vals))
+                    // For the second positional, lets not use possible_values() just to show the difference
+                    .arg_from_usage("<oof> 'The Oof to use'")
+                    .get_matches();
+
+    let t = value_t!(m.value_of("foo"), Foo).unwrap_or_else(|e| e.exit());
+    let t2 = value_t!(m.value_of("oof"), Oof).unwrap_or_else(|e| e.exit());
+
+
+    // Now we can use our enum like normal.
+    match t {
+        Foo::Bar => println!("Found a Bar"),
+        Foo::Baz => println!("Found a Baz"),
+        Foo::Qux => println!("Found a Qux")
+    }
+
+    // Since our Oof derives Debug, we can do this:
+    println!("Oof: {:?}", t2);
+}