Struct clap::Error [−][src]
Expand description
Command Line Argument Parser Error
See App::error
to create an error.
Fields
kind: ErrorKind
The type of error
info: Vec<String>
Additional information depending on the error kind, like values and argument names. Useful when you want to render an error of your own.
Implementations
Create an unformatted error
This is for you need to pass the error up to
a place that has access to the App
at which point you can call Error::format]. Prefer [
App::error` for generating errors.
Format the existing message with the App’s context
Should the message be written to stdout
or not?
Prints the error and exits.
Depending on the error kind, this either prints to stderr
and exits with a status of 1
or prints to stdout
and exits with a status of 0
.
Examples found in repository
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fn main() {
let cli = Cli::parse();
// Let's assume the old version 1.2.3
let mut major = 1;
let mut minor = 2;
let mut patch = 3;
// See if --set-ver was used to set the version manually
let version = if let Some(ver) = cli.set_ver.as_deref() {
if cli.major || cli.minor || cli.patch {
let mut app = Cli::into_app();
app.error(
ErrorKind::ArgumentConflict,
"Can't do relative and absolute version change",
)
.exit();
}
ver.to_string()
} else {
// Increment the one requested (in a real program, we'd reset the lower numbers)
let (maj, min, pat) = (cli.major, cli.minor, cli.patch);
match (maj, min, pat) {
(true, false, false) => major += 1,
(false, true, false) => minor += 1,
(false, false, true) => patch += 1,
_ => {
let mut app = Cli::into_app();
app.error(
ErrorKind::ArgumentConflict,
"Cam only modify one version field",
)
.exit();
}
};
format!("{}.{}.{}", major, minor, patch)
};
println!("Version: {}", version);
// Check for usage of -c
if let Some(config) = cli.config.as_deref() {
// todo: remove `#[allow(clippy::or_fun_call)]` lint when MSRV is bumped.
#[allow(clippy::or_fun_call)]
let input = cli
.input_file
.as_deref()
// 'or' is preferred to 'or_else' here since `Option::as_deref` is 'const'
.or(cli.spec_in.as_deref())
.unwrap_or_else(|| {
let mut app = Cli::into_app();
app.error(
ErrorKind::MissingRequiredArgument,
"INPUT_FILE or --spec-in is required when using --config",
)
.exit()
});
println!("Doing work using input {} and config {}", input, config);
}
}
More examples
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fn main() {
// Create application like normal
let mut app = app_from_crate!()
// Add the version arguments
.arg(arg!(--"set-ver" <VER> "set version manually").required(false))
.arg(arg!(--major "auto inc major"))
.arg(arg!(--minor "auto inc minor"))
.arg(arg!(--patch "auto inc patch"))
// Arguments can also be added to a group individually, these two arguments
// are part of the "input" group which is not required
.arg(arg!([INPUT_FILE] "some regular input"))
.arg(arg!(--"spec-in" <SPEC_IN> "some special input argument").required(false))
// Now let's assume we have a -c [config] argument which requires one of
// (but **not** both) the "input" arguments
.arg(arg!(config: -c <CONFIG>).required(false));
let matches = app.get_matches_mut();
// Let's assume the old version 1.2.3
let mut major = 1;
let mut minor = 2;
let mut patch = 3;
// See if --set-ver was used to set the version manually
let version = if let Some(ver) = matches.value_of("set-ver") {
if matches.is_present("major") || matches.is_present("minor") || matches.is_present("patch")
{
app.error(
ErrorKind::ArgumentConflict,
"Can't do relative and absolute version change",
)
.exit();
}
ver.to_string()
} else {
// Increment the one requested (in a real program, we'd reset the lower numbers)
let (maj, min, pat) = (
matches.is_present("major"),
matches.is_present("minor"),
matches.is_present("patch"),
);
match (maj, min, pat) {
(true, false, false) => major += 1,
(false, true, false) => minor += 1,
(false, false, true) => patch += 1,
_ => {
app.error(
ErrorKind::ArgumentConflict,
"Cam only modify one version field",
)
.exit();
}
};
format!("{}.{}.{}", major, minor, patch)
};
println!("Version: {}", version);
// Check for usage of -c
if matches.is_present("config") {
let input = matches
.value_of("INPUT_FILE")
.or_else(|| matches.value_of("spec-in"))
.unwrap_or_else(|| {
app.error(
ErrorKind::MissingRequiredArgument,
"INPUT_FILE or --spec-in is required when using --config",
)
.exit()
});
println!(
"Doing work using input {} and config {}",
input,
matches.value_of("config").unwrap()
);
}
}
Prints formatted and colored error to stdout
or stderr
according to its error kind
Example
use clap::App;
match App::new("App").try_get_matches() {
Ok(matches) => {
// do_something
},
Err(err) => {
err.print().expect("Error writing Error");
// do_something
},
};
👎 Deprecated since 3.0.0: Replaced with App::error
Replaced with App::error
Deprecated, replaced with App::error