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Diffstat (limited to 'clap/examples/12_typed_values.rs')
-rw-r--r-- | clap/examples/12_typed_values.rs | 50 |
1 files changed, 0 insertions, 50 deletions
diff --git a/clap/examples/12_typed_values.rs b/clap/examples/12_typed_values.rs deleted file mode 100644 index 3d03e4f..0000000 --- a/clap/examples/12_typed_values.rs +++ /dev/null @@ -1,50 +0,0 @@ -#[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); - } -} |