Add structopt dependency in version 0.3.7

This patch series replaces argparse with structopt in the argument
handling code. As a first step, we need structopt as a dependency.

Import subrepo structopt/:structopt at efbdda4753592e27bc430fb01f7b9650b2f3174d
Import subrepo bitflags/:bitflags at 30668016aca6bd3b02c766e8347e0b4080d4c296
Import subrepo clap/:clap at 784524f7eb193e35f81082cc69454c8c21b948f7
Import subrepo heck/:heck at 093d56fbf001e1506e56dbfa38631d99b1066df1
Import subrepo proc-macro-error/:proc-macro-error at 6c4cfe79a622c5de8ae68557993542be46eacae2
Import subrepo proc-macro2/:proc-macro2 at d5d48eddca4566e5438e8a2cbed4a74e049544de
Import subrepo quote/:quote at 727436c6c137b20f0f34dde5d8fda2679b9747ad
Import subrepo rustversion/:rustversion at 0c5663313516263059ce9059ef81fc7a1cf655ca
Import subrepo syn-mid/:syn-mid at 5d3d85414a9e6674e1857ec22a87b96e04a6851a
Import subrepo syn/:syn at e87c27e87f6f4ef8919d0372bdb056d53ef0d8f3
Import subrepo textwrap/:textwrap at abcd618beae3f74841032aa5b53c1086b0a57ca2
Import subrepo unicode-segmentation/:unicode-segmentation at 637c9874c4fe0c205ff27787faf150a40295c6c3
Import subrepo unicode-width/:unicode-width at 3033826f8bf05e82724140a981d5941e48fce393
Import subrepo unicode-xid/:unicode-xid at 4baae9fffb156ba229665b972a9cd5991787ceb7

1 files changed, 56 insertions, 0 deletions

diff --git a/clap/examples/06_positional_args.rs b/clap/examples/06_positional_args.rs
new file mode 100644
index 0000000..1f29612
--- /dev/null
+++ b/clap/examples/06_positional_args.rs
@@ -0,0 +1,56 @@
+extern crate clap;
+
+use clap::{App, Arg};
+
+fn main() {
+
+    // Positional arguments are those values after the program name which are not preceded by any
+    // identifier (such as "myapp some_file"). Positionals support many of the same options as
+    // flags, as well as a few additional ones.
+    let matches = App::new("MyApp")
+                        // Regular App configuration goes here...
+
+                        // We'll add two positional arguments, a input file, and a config file.
+                        //
+                        // I'll explain each possible setting that "positionals" accept. Keep in
+                        // mind that you DO NOT need to set each of these for every flag, only the
+                        // ones that apply to your individual case.
+                        .arg(Arg::with_name("input")
+                                    .help("the input file to use") // Displayed when showing help info
+                                    .index(1)                      // Set the order in which the user must
+                                                                   // specify this argument (Starts at 1)
+                                    .requires("config")            // Says, "If the user uses "input", they MUST
+                                                                   // also use this other 'config' arg too"
+                                                                   // Can also specify a list using
+                                                                   // requires_all(Vec<&str>)
+                                    .conflicts_with("output")      // Opposite of requires(), says "if the
+                                                                   // user uses -a, they CANNOT use 'output'"
+                                                                   // also has a conflicts_with_all(Vec<&str>)
+                                    .required(true)                // By default this argument MUST be present
+                                                                   // NOTE: mutual exclusions take precedence over
+                                                                   // required arguments
+                        )
+                        .arg(Arg::with_name("config")
+                                    .help("the config file to use")
+                                    .index(2))                     // Note, we do not need to specify required(true)
+                                                                   // if we don't want to, because "input" already
+                                                                   // requires "config"
+                                                                   // Note, we also do not need to specify requires("input")
+                                                                   // because requires lists are automatically two-way
+
+                        // NOTE: In order to compile this example, comment out conflicts_with()
+                        // because we have not defined an "output" argument.
+                        .get_matches();
+
+    // We can find out whether or not "input" or "config" were used
+    if matches.is_present("input") {
+        println!("An input file was specified");
+    }
+
+    // We can also get the values for those arguments
+    if let Some(in_file) = matches.value_of("input") {
+        // It's safe to call unwrap() because of the required options we set above
+        println!("Doing work with {} and {}", in_file, matches.value_of("config").unwrap());
+    }
+    // Continued program logic goes here...
+}