mirror of
https://github.com/clap-rs/clap
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94 lines
4 KiB
Rust
94 lines
4 KiB
Rust
/// `ArgGroup`s are a family of related arguments and way for you to say, "Any of these arguments".
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/// By placing arguments in a logical group, you can make easier requirement and exclusion rules
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/// instead of having to list each individually, or when you want a rule to apply "any but not all"
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/// arguments.
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///
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/// For instance, you can make an entire ArgGroup required, this means that one (and *only* one)
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/// argument. from that group must be present. Using more than one argument from an ArgGroup causes
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/// a failure (graceful exit).
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///
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/// You can also do things such as name an ArgGroup as a confliction or requirement, meaning any
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/// of the arguments that belong to that group will cause a failure if present, or must present
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/// respectively.
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///
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/// Perhaps the most common use of `ArgGroup`s is to require one and *only* one argument to be
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/// present out of a given set. Imagine that you had multiple arguments, and you want one of them to
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/// be required, but making all of them required isn't feasible because perhaps they conflict with
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/// each other. For example, lets say that you were building an application where one could set a
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/// given version number by supplying a string with an option argument, i.e. `--set-ver v1.2.3`, you
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/// also wanted to support automatically using a previous version number and simply incrementing one
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/// of the three numbers. So you create three flags `--major`, `--minor`, and `--patch`. All of
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/// these arguments shouldn't be used at one time but you want to specify that *at least one* of
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/// them is used. For this, you can create a group.
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use clap::{arg, App, Arg, ArgGroup};
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fn main() {
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// Create application like normal
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let matches = App::new("myapp")
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// Add the version arguments
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.arg(arg!(--"set-ver" <ver> "set version manually").required(false))
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.arg(arg!(--major "auto inc major"))
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.arg(arg!(--minor "auto inc minor"))
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.arg(arg!(--patch "auto inc patch"))
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// Create a group, make it required, and add the above arguments
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.group(
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ArgGroup::new("vers")
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.required(true)
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.args(&["set-ver", "major", "minor", "patch"]),
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)
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// Arguments can also be added to a group individually, these two arguments
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// are part of the "input" group which is not required
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.arg(arg!([INPUT_FILE] "some regular input").group("input"))
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.arg(
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arg!(--"spec-in" <SPEC_IN> "some special input argument")
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.required(false)
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.group("input"),
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)
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// Now let's assume we have a -c [config] argument which requires one of
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// (but **not** both) the "input" arguments
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.arg(
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Arg::new("config")
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.short('c')
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.takes_value(true)
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.requires("input"),
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)
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.get_matches();
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// Let's assume the old version 1.2.3
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let mut major = 1;
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let mut minor = 2;
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let mut patch = 3;
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// See if --set-ver was used to set the version manually
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let version = if let Some(ver) = matches.value_of("set-ver") {
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ver.to_string()
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} else {
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// Increment the one requested (in a real program, we'd reset the lower numbers)
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let (maj, min, pat) = (
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matches.is_present("major"),
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matches.is_present("minor"),
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matches.is_present("patch"),
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);
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match (maj, min, pat) {
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(true, _, _) => major += 1,
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(_, true, _) => minor += 1,
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(_, _, true) => patch += 1,
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_ => unreachable!(),
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};
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format!("{}.{}.{}", major, minor, patch)
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};
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println!("Version: {}", version);
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// Check for usage of -c
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if matches.is_present("config") {
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let input = matches
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.value_of("INPUT_FILE")
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.unwrap_or_else(|| matches.value_of("spec-in").unwrap());
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println!(
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"Doing work using input {} and config {}",
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input,
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matches.value_of("config").unwrap()
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);
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}
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}
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