Struct clap_builder::error::Error

source ·
pub struct Error<F: ErrorFormatter = DefaultFormatter> { /* private fields */ }
Expand description

Command Line Argument Parser Error

See Command::error to create an error.

Implementations§

source§

impl<F: ErrorFormatter> Error<F>

source

pub fn raw(kind: ErrorKind, message: impl Display) -> Self

Create an unformatted error

This is for you need to pass the error up to a place that has access to the Command at which point you can call Error::format.

Prefer Command::error for generating errors.

source

pub fn format(self, cmd: &mut Command) -> Self

Format the existing message with the Command’s context

source

pub fn new(kind: ErrorKind) -> Self

Create an error with a pre-defined message

See also

Example

let cmd = clap::Command::new("prog");

let mut err = clap::Error::new(ErrorKind::ValueValidation)
    .with_cmd(&cmd);
err.insert(ContextKind::InvalidArg, ContextValue::String("--foo".to_owned()));
err.insert(ContextKind::InvalidValue, ContextValue::String("bar".to_owned()));

err.print();
source

pub fn with_cmd(self, cmd: &Command) -> Self

Apply Command’s formatting to the error

Generally, this is used with Error::new

source

pub fn apply<EF: ErrorFormatter>(self) -> Error<EF>

Apply an alternative formatter to the error

Example
let cmd = Command::new("foo")
    .arg(Arg::new("input").required(true));
let matches = cmd
    .try_get_matches_from(["foo", "input.txt"])
    .map_err(|e| e.apply::<KindFormatter>())
    .unwrap_or_else(|e| e.exit());
source

pub fn kind(&self) -> ErrorKind

Type of error for programmatic processing

source

pub fn context(&self) -> impl Iterator<Item = (ContextKind, &ContextValue)>

Additional information to further qualify the error

source

pub fn get(&self, kind: ContextKind) -> Option<&ContextValue>

Lookup a piece of context

source

pub fn insert( &mut self, kind: ContextKind, value: ContextValue ) -> Option<ContextValue>

Insert a piece of context

source

pub fn use_stderr(&self) -> bool

Should the message be written to stdout or not?

source

pub fn exit(&self) -> !

Prints the error and exits.

Depending on the error kind, this either prints to stderr and exits with a status of 2 or prints to stdout and exits with a status of 0.

source

pub fn print(&self) -> Result<()>

Prints formatted and colored error to stdout or stderr according to its error kind

Example
use clap::Command;

match Command::new("Command").try_get_matches() {
    Ok(matches) => {
        // do_something
    },
    Err(err) => {
        err.print().expect("Error writing Error");
        // do_something
    },
};
source

pub fn render(&self) -> StyledStr

Render the error message to a StyledStr.

Example
use clap::Command;

match Command::new("Command").try_get_matches() {
    Ok(matches) => {
        // do_something
    },
    Err(err) => {
        let err = err.render();
        println!("{err}");
        // do_something
    },
};

Trait Implementations§

source§

impl<F: ErrorFormatter> Debug for Error<F>

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
source§

impl<F: ErrorFormatter> Display for Error<F>

source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
source§

impl<F: ErrorFormatter> Error for Error<F>

source§

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any. Read more
1.0.0 · source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
1.0.0 · source§

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
source§

fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type based access to context intended for error reports. Read more
source§

impl<F: ErrorFormatter> From<Error> for Error<F>

source§

fn from(e: Error) -> Self

Converts to this type from the input type.
source§

impl<F: ErrorFormatter> From<Error> for Error<F>

source§

fn from(e: Error) -> Self

Converts to this type from the input type.

Auto Trait Implementations§

§

impl<F = RichFormatter> !RefUnwindSafe for Error<F>

§

impl<F> Send for Error<F>where F: Send,

§

impl<F> Sync for Error<F>where F: Sync,

§

impl<F> Unpin for Error<F>where F: Unpin,

§

impl<F = RichFormatter> !UnwindSafe for Error<F>

Blanket Implementations§

source§

impl<T> Any for Twhere T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<E> Provider for Ewhere E: Error + ?Sized,

source§

fn provide<'a>(&'a self, demand: &mut Demand<'a>)

🔬This is a nightly-only experimental API. (provide_any)
Data providers should implement this method to provide all values they are able to provide by using demand. Read more
source§

impl<T> ToString for Twhere T: Display + ?Sized,

source§

default fn to_string(&self) -> String

Converts the given value to a String. Read more
source§

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.