From 5e20a29b4fdc8a2d442d1093681b396dcb4b816b Mon Sep 17 00:00:00 2001 From: Robin Krahl Date: Tue, 7 Jan 2020 11:18:04 +0000 Subject: 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 --- clap/examples/12_typed_values.rs | 50 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 clap/examples/12_typed_values.rs (limited to 'clap/examples/12_typed_values.rs') 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) + // + // 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 or Result,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 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( + "... '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); + } +} -- cgit v1.2.1