pub trait Display {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
Expand description
Format trait for an empty format, {}
.
Implementing this trait for a type will automatically implement the
ToString
trait for the type, allowing the usage
of the .to_string()
method. Prefer implementing
the Display
trait for a type, rather than ToString
.
Display
is similar to Debug
, but Display
is for user-facing
output, and so cannot be derived.
For more information on formatters, see the module-level documentation.
§Completeness and parseability
Display
for a type might not necessarily be a lossless or complete representation of the type.
It may omit internal state, precision, or other information the type does not consider important
for user-facing output, as determined by the type. As such, the output of Display
might not be
possible to parse, and even if it is, the result of parsing might not exactly match the original
value.
However, if a type has a lossless Display
implementation whose output is meant to be
conveniently machine-parseable and not just meant for human consumption, then the type may wish
to accept the same format in FromStr
, and document that usage. Having both Display
and
FromStr
implementations where the result of Display
cannot be parsed with FromStr
may
surprise users.
§Internationalization
Because a type can only have one Display
implementation, it is often preferable
to only implement Display
when there is a single most “obvious” way that
values can be formatted as text. This could mean formatting according to the
“invariant” culture and “undefined” locale, or it could mean that the type
display is designed for a specific culture/locale, such as developer logs.
If not all values have a justifiably canonical textual format or if you want
to support alternative formats not covered by the standard set of possible
formatting traits, the most flexible approach is display adapters: methods
like str::escape_default
or Path::display
which create a wrapper
implementing Display
to output the specific display format.
§Examples
Implementing Display
on a type:
use std::fmt;
struct Point {
x: i32,
y: i32,
}
impl fmt::Display for Point {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "({}, {})", self.x, self.y)
}
}
let origin = Point { x: 0, y: 0 };
assert_eq!(format!("The origin is: {origin}"), "The origin is: (0, 0)");
Required Methods§
1.0.0 · Sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter.
§Errors
This function should return Err
if, and only if, the provided Formatter
returns Err
.
String formatting is considered an infallible operation; this function only
returns a Result
because writing to the underlying stream might fail and it must
provide a way to propagate the fact that an error has occurred back up the stack.
§Examples
use std::fmt;
struct Position {
longitude: f32,
latitude: f32,
}
impl fmt::Display for Position {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "({}, {})", self.longitude, self.latitude)
}
}
assert_eq!(
"(1.987, 2.983)",
format!("{}", Position { longitude: 1.987, latitude: 2.983, }),
);
Implementors§
impl Display for fs_mistrust::err::Error
impl Display for tor_general_addr::general::AddrParseError
impl Display for InstallRuntimeError
impl Display for tor_memquota::Error
impl Display for StartupError
impl Display for ReclaimCrashed
impl Display for ReclaimedErrorInner
impl Display for Outcome
impl Display for ConfigBuildError
impl Display for tor_memquota::internal_prelude::ErrorKind
impl Display for ReconfigureError
impl Display for Void
impl Display for core::ascii::ascii_char::AsciiChar
impl Display for Infallible
impl Display for FromBytesWithNulError
impl Display for IpAddr
impl Display for SocketAddr
impl Display for core::slice::GetDisjointMutError
impl Display for VarError
impl Display for std::fs::TryLockError
impl Display for std::io::error::ErrorKind
impl Display for RecvTimeoutError
impl Display for std::sync::mpsc::TryRecvError
impl Display for TokioTpErr
impl Display for FromHexError
impl Display for log::Level
impl Display for log::LevelFilter
impl Display for DeserializerError
impl Display for SerializerError
impl Display for serde_json::value::Value
impl Display for url::parser::ParseError
impl Display for SyntaxViolation
impl Display for BernoulliError
impl Display for rand::distr::uniform::Error
impl Display for rand::distr::weighted::Error
impl Display for bool
impl Display for char
impl Display for f16
impl Display for f32
impl Display for f64
impl Display for i8
impl Display for i16
impl Display for i32
impl Display for i64
impl Display for i128
impl Display for isize
impl Display for !
impl Display for str
impl Display for u8
impl Display for u16
impl Display for u32
impl Display for u64
impl Display for u128
impl Display for usize
impl Display for NoAfUnixSocketSupport
impl Display for TrackerCorrupted
impl Display for ClaimedQty
impl Display for ParticipQty
impl Display for TotalQty
impl Display for Overflow
impl Display for MemoryReclaimedError
impl Display for tor_memquota::internal_prelude::mpsc::SendError
impl Display for tor_memquota::internal_prelude::mpsc::TryRecvError
impl Display for Bug
impl Display for ByteQty
impl Display for SpawnError
impl Display for ByteString
impl Display for UnorderedKeyError
impl Display for alloc::collections::TryReserveError
impl Display for FromVecWithNulError
impl Display for IntoStringError
impl Display for NulError
impl Display for FromUtf8Error
impl Display for FromUtf16Error
impl Display for String
impl Display for LayoutError
impl Display for AllocError
impl Display for TryFromSliceError
impl Display for core::ascii::EscapeDefault
impl Display for ByteStr
impl Display for BorrowError
impl Display for BorrowMutError
impl Display for CharTryFromError
impl Display for ParseCharError
impl Display for DecodeUtf16Error
impl Display for core::char::EscapeDebug
impl Display for core::char::EscapeDefault
impl Display for core::char::EscapeUnicode
impl Display for ToLowercase
impl Display for ToUppercase
impl Display for TryFromCharError
impl Display for FromBytesUntilNulError
impl Display for Ipv4Addr
impl Display for Ipv6Addr
Writes an Ipv6Addr, conforming to the canonical style described by RFC 5952.
impl Display for core::net::parser::AddrParseError
impl Display for SocketAddrV4
impl Display for SocketAddrV6
impl Display for core::num::dec2flt::ParseFloatError
impl Display for ParseIntError
impl Display for TryFromIntError
impl Display for Location<'_>
impl Display for PanicInfo<'_>
impl Display for PanicMessage<'_>
impl Display for ParseBoolError
impl Display for Utf8Error
impl Display for TryFromFloatSecsError
impl Display for Backtrace
impl Display for JoinPathsError
impl Display for std::ffi::os_str::Display<'_>
impl Display for WriterPanicked
impl Display for std::io::error::Error
impl Display for PanicHookInfo<'_>
impl Display for std::path::Display<'_>
impl Display for NormalizeError
impl Display for StripPrefixError
impl Display for ExitStatus
impl Display for ExitStatusError
impl Display for std::sync::mpsc::RecvError
impl Display for std::thread::local::AccessError
impl Display for SystemTimeError
impl Display for async_executors::iface::timer::TimeoutError
impl Display for getrandom::error::Error
impl Display for log::kv::error::Error
impl Display for log::ParseLevelError
impl Display for SetLoggerError
impl Display for num_traits::ParseFloatError
impl Display for Asn1GeneralizedTimeRef
impl Display for Asn1ObjectRef
impl Display for Asn1TimeRef
impl Display for BigNum
impl Display for BigNumRef
impl Display for openssl::error::Error
impl Display for ErrorStack
impl Display for openssl::ssl::error::Error
impl Display for OpensslString
impl Display for OpensslStringRef
impl Display for X509VerifyResult
impl Display for serde::de::value::Error
impl Display for serde_json::error::Error
impl Display for Number
impl Display for RawValue
impl Display for Url
Display the serialization of this URL.
impl Display for value_bag::error::Error
impl Display for Empty
impl Display for OsError
impl Display for Arguments<'_>
impl Display for tor_memquota::internal_prelude::fmt::Error
impl Display for Aborted
impl Display for AccessError
impl Display for AcquireError
impl Display for Actual
impl Display for AddrParseError
impl Display for AnyDelimiterCodecError
impl Display for Array
impl Display for ArrayOfTables
impl Display for AsAsciiStrError
impl Display for AsciiChar
impl Display for AsciiStr
impl Display for AsciiString
impl Display for Ast
Print a display representation of this Ast.
This does not preserve any of the original whitespace formatting that may have originally been present in the concrete syntax from which this Ast was generated.
This implementation uses constant stack space and heap space proportional
to the size of the Ast
.
impl Display for Attribute
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Attributes
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for BStr
impl Display for BigEndian
impl Display for BinaryError
impl Display for BuildError
impl Display for BuildError
impl Display for Bytes
impl Display for Canceled
impl Display for CaseFoldError
impl Display for CertificateError
impl Display for CollectionAllocErr
impl Display for ConfigError
impl Display for ConfigResolveError
impl Display for ContextError
impl Display for DataError
impl Display for DataErrorKind
impl Display for DataIdentifierBorrowed<'_>
impl Display for DataLocale
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Date
impl Display for Datetime
impl Display for DatetimeParseError
impl Display for DeserializeError
impl Display for DisfavouredKey
impl Display for DivError
impl Display for DocumentMut
impl Display for Duration
impl Display for EarlyDataError
impl Display for Elapsed
impl Display for EmptyError
impl Display for EncodeError
impl Display for EncryptError
impl Display for EnterError
impl Display for ErasedSinkTrySendError
impl Display for Errno
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for Error
impl Display for ErrorKind
impl Display for ErrorKind
impl Display for Errors
impl Display for ExtendedKeyPurpose
impl Display for Field
impl Display for FieldSet
impl Display for Fields
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for FileTime
impl Display for FileWatcherBuildError
impl Display for FloatIsNan
impl Display for FormattedDuration
impl Display for FromStrError
impl Display for GetDisjointMutError
impl Display for GroupInfoError
impl Display for Hir
Print a display representation of this Hir.
The result of this is a valid regular expression pattern string.
This implementation uses constant stack space and heap space proportional
to the size of the Hir
.
impl Display for Id
impl Display for InlineTable
impl Display for InternalString
impl Display for InvalidBoolOrAuto
impl Display for InvalidDnsNameError
impl Display for InvalidListen
impl Display for InvalidSetError
impl Display for InvalidStringList
impl Display for Item
impl Display for JoinError
impl Display for JsonCodecError
impl Display for Key
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Key
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Key
impl Display for KeyMut<'_>
impl Display for KeyRejected
impl Display for Keywords
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Kind
impl Display for Language
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for LanguageIdentifier
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for LengthDelimitedCodecError
impl Display for Level
impl Display for LevelFilter
impl Display for LinesCodecError
impl Display for Listen
impl Display for ListenUnsupported
impl Display for LittleEndian
impl Display for Locale
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Map<String, Value>
impl Display for MatchError
impl Display for MaxRecursionReached
impl Display for MpscOtherSinkTrySendError
impl Display for NonUtf8Error
impl Display for Offset
impl Display for OneOf
impl Display for Other
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for OtherError
impl Display for OverflowError
impl Display for PaddingLevel
impl Display for ParseError
impl Display for ParseError
impl Display for ParseError
impl Display for ParseError
impl Display for ParseLengthError
impl Display for ParseLevelError
impl Display for ParseLevelFilterError
impl Display for PatternIDError
impl Display for PatternSetInsertError
impl Display for PopError
impl Display for PositDecodeError
impl Display for PreferencesParseError
impl Display for Private
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Profile
impl Display for Range
impl Display for RangeError
impl Display for RecvError
impl Display for RecvError
impl Display for RecvError
impl Display for RecvError
impl Display for RecvError
impl Display for Regex
impl Display for Regex
impl Display for Region
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for ReuniteError
impl Display for ReuniteError
impl Display for Rfc3339Timestamp
impl Display for Script
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for SerializeError
impl Display for SetGlobalDefaultError
impl Display for SleepError
impl Display for SmallIndexError
impl Display for Source
Displays the source. Location and custom sources are displayed directly. File paths are displayed relative to the current working directory if the relative path is shorter than the complete path.
impl Display for StartError
impl Display for StateIDError
impl Display for StrContext
impl Display for StrContextValue
impl Display for SubdivisionId
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for SubdivisionSuffix
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Subtag
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Subtag
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Table
impl Display for TaskId
impl Display for Time
impl Display for TimeoutError
impl Display for TimeoutError
impl Display for TimeoutError
impl Display for Timestamp
impl Display for ToAsciiCharError
impl Display for TomlError
Displays a TOML parse error
§Example
TOML parse error at line 1, column 10
|
1 | 00:32:00.a999999
| ^
Unexpected a
Expected digit
While parsing a Time
While parsing a Date-Time
impl Display for TooLargeBufferRequiredError
impl Display for Transform
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Truncated
impl Display for TryAcquireError
impl Display for TryCurrentError
impl Display for TryGetError
impl Display for TryLockError
impl Display for TryRecvError
impl Display for TryRecvError
impl Display for TryRecvError
impl Display for TryRecvError
impl Display for TryRecvError
impl Display for TryRecvError
impl Display for TryReserveError
impl Display for UleError
impl Display for Uncased<'_>
impl Display for UncasedStr
impl Display for UnexpectedNullPointerError
impl Display for Unicode
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for UnicodeWordBoundaryError
impl Display for UnicodeWordError
impl Display for UninitializedFieldError
impl Display for UnitError
impl Display for Unspecified
impl Display for UnsupportedAddress
impl Display for UnsupportedAfUnixAddressType
impl Display for UnsupportedOperationError
impl Display for UnsupportedStreamOp
impl Display for Utf8CharsError
impl Display for Value
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Value
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Value
impl Display for Value
impl Display for Variant
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for Variants
This trait is implemented for compatibility with fmt!
.
To create a string, [Writeable::write_to_string
] is usually more efficient.
impl Display for VerifierBuilderError
impl Display for WrongVariantError
impl Display for ZeroTrieBuildError
impl Display for dyn Expected + '_
impl Display for dyn Value
impl Display for i256
impl Display for i512
impl Display for i1024
impl Display for u1
impl Display for u2
impl Display for u3
impl Display for u4
impl Display for u5
impl Display for u6
impl Display for u7
impl Display for u24
impl Display for u40
impl Display for u48
impl Display for u56
impl Display for u256
impl Display for u512
impl Display for u1024
impl<'a> Display for Unexpected<'a>
impl<'a> Display for Path<'a>
impl<'a> Display for AnonHomePath<'a>
impl<'a> Display for DisplayLossy<'a>
impl<'a> Display for EscapeAscii<'a>
impl<'a> Display for core::str::iter::EscapeDebug<'a>
impl<'a> Display for core::str::iter::EscapeDefault<'a>
impl<'a> Display for core::str::iter::EscapeUnicode<'a>
impl<'a> Display for DisplayFracRejected<'a>
impl<'a> Display for PercentEncode<'a>
impl<'a> Display for ValueSet<'a>
impl<'a, I> Display for Format<'a, I>
impl<'a, K, V> Display for std::collections::hash::map::OccupiedError<'a, K, V>
impl<'a, K, V, A> Display for alloc::collections::btree::map::entry::OccupiedError<'a, K, V, A>
impl<'a, R, G, T> Display for MappedReentrantMutexGuard<'a, R, G, T>
impl<'a, R, G, T> Display for ReentrantMutexGuard<'a, R, G, T>
impl<'a, R, T> Display for MappedMutexGuard<'a, R, T>
impl<'a, R, T> Display for MappedRwLockReadGuard<'a, R, T>
impl<'a, R, T> Display for MappedRwLockWriteGuard<'a, R, T>
impl<'a, R, T> Display for MutexGuard<'a, R, T>
impl<'a, R, T> Display for RwLockReadGuard<'a, R, T>
impl<'a, R, T> Display for RwLockUpgradableReadGuard<'a, R, T>
impl<'a, R, T> Display for RwLockWriteGuard<'a, R, T>
impl<'a, T> Display for MappedMutexGuard<'a, T>
impl<'a, T> Display for RwLockMappedWriteGuard<'a, T>
impl<'a, T> Display for RwLockReadGuard<'a, T>
impl<'a, T> Display for RwLockWriteGuard<'a, T>
impl<'k> Display for log::kv::key::Key<'k>
impl<'v> Display for log::kv::value::Value<'v>
impl<'v> Display for ValueBag<'v>
impl<A, S, V> Display for ConvertError<A, S, V>
Produces a human-readable error message.
The message differs between debug and release builds. When
debug_assertions
are enabled, this message is verbose and includes
potentially sensitive information.
impl<B> Display for Cow<'_, B>
impl<CE> Display for tor_memquota::mq_queue::SendError<CE>
impl<E> Display for std::error::Report<E>where
E: Error,
impl<E> Display for ErrMode<E>where
E: Debug,
impl<E> Display for MultilineListBuilderError<E>
impl<E> Display for ParseNotNanError<E>where
E: Display,
impl<E> Display for Report<E>
impl<E> Display for RetryError<E>
impl<E> Display for SubfieldBuildError<E>where
E: Display,
impl<F> Display for FromFn<F>
impl<I> Display for ExactlyOneError<I>where
I: Iterator,
impl<I> Display for InputError<I>
The Display implementation allows the std::error::Error
implementation
impl<I> Display for LocatingSlice<I>where
I: Display,
impl<I> Display for Partial<I>where
I: Display,
impl<I> Display for TreeErrorBase<I>where
I: Display,
impl<I, C> Display for TreeError<I, C>
impl<I, C> Display for TreeErrorContext<I, C>
impl<I, E> Display for ParseError<I, E>where
I: AsBStr,
E: Display,
impl<I, F> Display for FormatWith<'_, I, F>
impl<I, S> Display for Stateful<I, S>where
I: Display,
impl<K, V, S, A> Display for OccupiedError<'_, K, V, S, A>
impl<L, R> Display for Either<L, R>
impl<O> Display for F32<O>where
O: ByteOrder,
impl<O> Display for F64<O>where
O: ByteOrder,
impl<O> Display for FromAsciiError<O>
impl<O> Display for I16<O>where
O: ByteOrder,
impl<O> Display for I32<O>where
O: ByteOrder,
impl<O> Display for I64<O>where
O: ByteOrder,
impl<O> Display for I128<O>where
O: ByteOrder,
impl<O> Display for Isize<O>where
O: ByteOrder,
impl<O> Display for U16<O>where
O: ByteOrder,
impl<O> Display for U32<O>where
O: ByteOrder,
impl<O> Display for U64<O>where
O: ByteOrder,
impl<O> Display for U128<O>where
O: ByteOrder,
impl<O> Display for Usize<O>where
O: ByteOrder,
impl<Ptr> Display for Pin<Ptr>where
Ptr: Display,
impl<S> Display for openssl::ssl::error::HandshakeError<S>where
S: Debug,
impl<S> Display for Host<S>
impl<S> Display for HandshakeError<S>
impl<Src, Dst> Display for AlignmentError<Src, Dst>
Produces a human-readable error message.
The message differs between debug and release builds. When
debug_assertions
are enabled, this message is verbose and includes
potentially sensitive information.
impl<Src, Dst> Display for SizeError<Src, Dst>
Produces a human-readable error message.
The message differs between debug and release builds. When
debug_assertions
are enabled, this message is verbose and includes
potentially sensitive information.
impl<Src, Dst> Display for ValidityError<Src, Dst>
Produces a human-readable error message.
The message differs between debug and release builds. When
debug_assertions
are enabled, this message is verbose and includes
potentially sensitive information.