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, 71 insertions, 0 deletions

diff --git a/clap/examples/07_option_args.rs b/clap/examples/07_option_args.rs
new file mode 100644
index 0000000..85ff0e5
--- /dev/null
+++ b/clap/examples/07_option_args.rs
@@ -0,0 +1,71 @@
+extern crate clap;
+
+use clap::{App, Arg};
+
+fn main() {
+
+    // Option arguments are those that take an additional value, such as "-c value". In clap they
+    // support three types of specification, those with short() as "-o some", or those with long()
+    // as "--option value" or "--option=value"
+    //
+    // Options also support a multiple setting, which is discussed in the example below.
+    let matches = App::new("MyApp")
+                        // Regular App configuration goes here...
+
+                        // Assume we have an application that accepts an input file via the "-i file"
+                        // or the "--input file" (as well as "--input=file").
+                        // Below every setting supported by option arguments is discussed.
+                        // NOTE: You DO NOT need to specify each setting, only those which apply
+                        // to your particular case.
+                        .arg(Arg::with_name("input")
+                                    .help("the input file to use") // Displayed when showing help info
+                                    .takes_value(true)             // MUST be set to true in order to be an "option" argument
+                                    .short("i")                    // This argument is triggered with "-i"
+                                    .long("input")                 // This argument is triggered with "--input"
+                                    .multiple(true)                // Set to true if you wish to allow multiple occurrences
+                                                                   // such as "-i file -i other_file -i third_file"
+                                    .required(true)                // By default this argument MUST be present
+                                                                   // NOTE: mutual exclusions take precedence over
+                                                                   // required arguments
+                                    .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>)
+                        )
+                        // NOTE: In order to compile this example, comment out conflicts_with()
+                        // and requires() because we have not defined an "output" or "config"
+                        // argument.
+                        .get_matches();
+
+    // We can find out whether or not "input" was used
+    if matches.is_present("input") {
+        println!("An input file was specified");
+    }
+
+    // We can also get the value for "input"
+    //
+    // NOTE: If we specified multiple(), this will only return the _FIRST_
+    // occurrence
+    if let Some(in_file) = matches.value_of("input") {
+        println!("An input file: {}", in_file);
+    }
+
+    // If we specified the multiple() setting we can get all the values
+    if let Some(in_v) = matches.values_of("input") {
+        for in_file in in_v {
+            println!("An input file: {}", in_file);
+        }
+    }
+
+    // We can see how many times the option was used with the occurrences_of() method
+    //
+    // NOTE: Just like with flags, if we did not specify the multiple() setting this will only
+    // return 1 no matter how many times the argument was used (unless it wasn't used at all, in
+    // in which case 0 is returned)
+    println!("The \"input\" argument was used {} times", matches.occurrences_of("input"));
+
+    // Continued program logic goes here...
+}