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/15_custom_validator.rs | 37 ++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 clap/examples/15_custom_validator.rs (limited to 'clap/examples/15_custom_validator.rs') diff --git a/clap/examples/15_custom_validator.rs b/clap/examples/15_custom_validator.rs new file mode 100644 index 0000000..a5c0d42 --- /dev/null +++ b/clap/examples/15_custom_validator.rs @@ -0,0 +1,37 @@ +extern crate clap; + +use clap::{App, Arg}; + +fn main() { + // You can define a function (or a closure) to use as a validator to argument values. The + // function must accept a String and return Result<(), String> where Err(String) is the message + // displayed to the user. + + let matches = App::new("myapp") + // Application logic goes here... + .arg(Arg::with_name("input") + .help("the input file to use") + .index(1) + .required(true) + // You can pass in a closure, or a function + .validator(is_png)) + .get_matches(); + + // Here we can call .unwrap() because the argument is required. + println!("The .PNG file is: {}", matches.value_of("input").unwrap()); +} + +fn is_png(val: String) -> Result<(), String> { + // val is the argument value passed in by the user + // val has type of String. + if val.ends_with(".png") { + Ok(()) + } else { + // clap automatically adds "error: " to the beginning + // of the message. + Err(String::from("the file format must be png.")) + } + // Of course, you can do more complicated validation as + // well, but for the simplicity, this example only checks + // if the value passed in ends with ".png" or not. +} -- cgit v1.2.1