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, 50 insertions, 0 deletions

diff --git a/clap/examples/12_typed_values.rs b/clap/examples/12_typed_values.rs
new file mode 100644
index 0000000..3d03e4f
--- /dev/null
+++ b/clap/examples/12_typed_values.rs
@@ -0,0 +1,50 @@
+#[macro_use]
+extern crate clap;
+
+use clap::App;
+
+fn main() {
+    // You can use some convenience macros provided by clap to get typed values, so long as the
+    // type you specify implements std::str::FromStr
+    //
+    // This works for both single, and multiple values (multiple values returns a Vec<T>)
+    //
+    // There are also two ways in which to get types, those where failures cause the program to exit
+    // with an error and usage string, and those which return a Result<T,String> or Result<Vec<T>,String>
+    // respectively. Both methods support single and multiple values.
+    //
+    // The macro which returns a Result allows you decide what to do upon a failure, exit, provide a
+    // default value, etc. You have control. But it also means you have to write the code or boiler plate
+    // to handle those instances.
+    //
+    // That is why the second method exists, so you can simply get a T or Vec<T> back, or be sure the
+    // program will exit gracefully. The catch is, the second method should *only* be used on required
+    // arguments, because if the argument isn't found, it exits. Just FYI ;)
+    //
+    // The following example shows both methods.
+    //
+    // **NOTE:** to use the macros, you must include #[macro_use] just above the 'extern crate clap;'
+    // declaration in your crate root.
+    let matches = App::new("myapp")
+                        // Create two arguments, a required positional which accepts multiple values
+                        // and an optional '-l value'
+                        .args_from_usage(
+                            "<seq>... 'A sequence of whole positive numbers, i.e. 20 25 30'
+                            -l [len] 'A length to use, defaults to 10 when omitted'")
+                        .get_matches();
+
+    // Here we get a value of type u32 from our optional -l argument.
+    // If the value provided to len fails to parse, we default to 10
+    //
+    // Using other methods such as unwrap_or_else(|e| println!("{}",e))
+    // are possible too.
+    let len = value_t!(matches, "len", u32).unwrap_or(10);
+
+    println!("len ({}) + 2 = {}", len, len + 2);
+
+    // This code loops through all the values provided to "seq" and adds 2
+    // If seq fails to parse, the program exits, you don't have an option
+    for v in values_t!(matches, "seq", u32).unwrap_or_else(|e| e.exit()) {
+        println!("Sequence part {} + 2: {}", v, v + 2);
+    }
+}