Enum ParseError 

pub enum ParseError {
    MissingRequired(String),
    MissingValue(String),
    UnknownArgument(String),
    InvalidFormat(String),
    HelpRequested(String),
    VersionRequested(String),
    NoSubcommand(String),
    UnknownSubcommand(String),
    DuplicateOption(String),
    InvalidUtf8(String),
    ValidationFailed {
        name: String,
        message: String,
    },
    GroupViolation {
        group: String,
        members: Vec<String>,
    },
    ConflictViolation {
        conflict: String,
        provided: Vec<String>,
    },
}

Errors produced during argument parsing.

The HelpRequested and VersionRequested variants carry the formatted text that should be printed to stdout. All other variants represent actual errors and carry a descriptive message suitable for display.

Implements std::fmt::Display and std::error::Error. When the color feature is enabled, the Display output includes ANSI styling.

Variants

MissingRequired(String)

A required argument was not provided. Contains the argument name.

MissingValue(String)

An option was provided without a value. Contains the option name.

UnknownArgument(String)

An unrecognized argument was encountered. Contains the raw token.

InvalidFormat(String)

A structural error in the parser definition. Contains a description.

HelpRequested(String)

The -h / --help flag was encountered. Contains the formatted help text.

VersionRequested(String)

The -V / --version flag was encountered. Contains the formatted version text.

NoSubcommand(String)

A subcommand was expected but none was provided. Contains available names.

UnknownSubcommand(String)

An unrecognized subcommand was provided. Contains the unknown name.

DuplicateOption(String)

A non-multi option was provided more than once. Contains the option name.

InvalidUtf8(String)

A command-line argument contained bytes that are not valid UTF-8. Contains the lossy representation.

ValidationFailed

A value failed validation. Contains the argument name and error message.

Fields

name: String

The argument name (e.g. option long name or positional name).

message: String

The human-readable validation error message.

GroupViolation

An argument group constraint was violated: none of the members were provided.

Fields

group: String

The group name.

members: Vec<String>

Long names of the group’s member arguments.

ConflictViolation

A conflict set constraint was violated: two or more mutually exclusive members were provided.

Fields

conflict: String

The conflict set name.

provided: Vec<String>

Long names of the conflicting arguments that were provided.

Trait Implementations

impl Clone for ParseError

fn clone(&self) -> ParseError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ParseError

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

Formats the value using the given formatter.

impl Display for ParseError

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

Formats the value using the given formatter.

impl Eq for ParseError

impl Error for ParseError

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

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

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

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for ParseError

fn eq(&self, other: &ParseError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ParseError