Trait Display

pub trait Display {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

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.

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

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 WaiterError

impl Display for Trap

impl Display for ImportError

impl Display for InstantiationError

impl Display for LinkError

impl Display for ObjectError

impl Display for RelocationKind

impl Display for RecvTimeoutError

impl Display for TryRecvError

impl Display for AsciiChar

impl Display for Infallible

impl Display for IpAddr

impl Display for SocketAddr

impl Display for VarError

impl Display for ErrorKind

impl Display for FromHexError

impl Display for bool

impl Display for char

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 UnorderedKeyError

impl Display for wasmer_compiler::lib::std::collections::TryReserveError

impl Display for ParseBoolError

impl Display for wasmer_compiler::lib::std::str::Utf8Error

impl Display for FromUtf8Error

impl Display for FromUtf16Error

impl Display for String

impl Display for RecvError

impl Display for FromVecWithNulError

impl Display for IntoStringError

impl Display for NulError

impl Display for LayoutError

impl Display for AllocError

impl Display for TryFromSliceError

impl Display for core::ascii::EscapeDefault

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 FromBytesWithNulError

impl Display for Ipv4Addr

impl Display for Ipv6Addr

Writes an Ipv6Addr, conforming to the canonical style described by RFC 5952.

impl Display for AddrParseError

impl Display for SocketAddrV4

impl Display for SocketAddrV6

impl Display for ParseFloatError

impl Display for ParseIntError

impl Display for TryFromIntError

impl Display for Location<'_>

impl Display for PanicInfo<'_>

impl Display for PanicMessage<'_>

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 StripPrefixError

impl Display for ExitStatus

impl Display for ExitStatusError

impl Display for AccessError

impl Display for SystemTimeError

impl Display for CompressError

impl Display for flate2::mem::DecompressError

impl Display for getrandom::error::Error

impl Display for serde::de::value::Error

impl Display for Arguments<'_>

impl Display for wasmer_compiler::lib::std::fmt::Error

impl Display for Aarch64Architecture

impl Display for Architecture

impl Display for ArchivedString

impl Display for ArmArchitecture

impl Display for BigEndian

impl Display for BinaryFormat

impl Display for BinaryReaderError

impl Display for BlockHeaderReadError

impl Display for BlockSizeError

impl Display for BlockType

impl Display for BlockTypeError

impl Display for BoxedError

impl Display for CollectionAllocErr

impl Display for CompileError

impl Display for CompositeType

impl Display for CpuFeature

impl Display for DecodeBlockContentError

impl Display for DecodeSequenceError

impl Display for DecodebufferError

impl Display for DecompressBlockError

impl Display for DecompressError

impl Display for DecompressLiteralsError

impl Display for DeserializeError

impl Display for DictionaryDecodeError

impl Display for DwAccess

impl Display for DwAddr

impl Display for DwAt

impl Display for DwAte

impl Display for DwCc

impl Display for DwCfa

impl Display for DwChildren

impl Display for DwDefaulted

impl Display for DwDs

impl Display for DwDsc

impl Display for DwEhPe

impl Display for DwEnd

impl Display for DwForm

impl Display for DwId

impl Display for DwIdx

impl Display for DwInl

impl Display for DwLang

impl Display for DwLle

impl Display for DwLnct

impl Display for DwLne

impl Display for DwLns

impl Display for DwMacro

impl Display for DwOp

impl Display for DwOrd

impl Display for DwRle

impl Display for DwSect

impl Display for DwSectV2

impl Display for DwTag

impl Display for DwUt

impl Display for DwVirtuality

impl Display for DwVis

impl Display for Environment

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 ExecuteSequencesError

impl Display for FSEDecoderError

impl Display for FSETableError

impl Display for Failure

impl Display for FrameDecoderError

impl Display for FrameDescriptorError

impl Display for FrameHeaderError

impl Display for FunctionType

impl Display for GetBitsError

impl Display for GetDisjointMutError

impl Display for GlobalType

impl Display for HuffmanDecoderError

impl Display for HuffmanTableError

impl Display for InvalidBufferSize

impl Display for InvalidLength

impl Display for InvalidOutputSize

impl Display for IteratorLengthMismatch

impl Display for LibCall

impl Display for LiteralsSectionParseError

impl Display for LiteralsSectionType

impl Display for LittleEndian

impl Display for MemoryError

impl Display for MemoryType

impl Display for MiddlewareError

impl Display for Mips32Architecture

impl Display for Mips64Architecture

impl Display for MmapError

impl Display for ModuleHash

impl Display for ModuleInfo

impl Display for NamedEnumVariantCheckContext

impl Display for NonZeroI16_be

impl Display for NonZeroI16_le

impl Display for NonZeroI16_ube

impl Display for NonZeroI16_ule

impl Display for NonZeroI32_be

impl Display for NonZeroI32_le

impl Display for NonZeroI32_ube

impl Display for NonZeroI32_ule

impl Display for NonZeroI64_be

impl Display for NonZeroI64_le

impl Display for NonZeroI64_ube

impl Display for NonZeroI64_ule

impl Display for NonZeroI128_be

impl Display for NonZeroI128_le

impl Display for NonZeroI128_ube

impl Display for NonZeroI128_ule

impl Display for NonZeroU16_be

impl Display for NonZeroU16_le

impl Display for NonZeroU16_ube

impl Display for NonZeroU16_ule

impl Display for NonZeroU32_be

impl Display for NonZeroU32_le

impl Display for NonZeroU32_ube

impl Display for NonZeroU32_ule

impl Display for NonZeroU64_be

impl Display for NonZeroU64_le

impl Display for NonZeroU64_ube

impl Display for NonZeroU64_ule

impl Display for NonZeroU128_be

impl Display for NonZeroU128_le

impl Display for NonZeroU128_ube

impl Display for NonZeroU128_ule

impl Display for OperatingSystem

impl Display for PackedIndex

impl Display for PageCountOutOfRange

impl Display for Panic

impl Display for ParseCpuFeatureError

impl Display for ParseError

impl Display for ParseError

impl Display for PreInstantiationError

impl Display for Protection

impl Display for ReadFrameHeaderError

impl Display for RefType

impl Display for Riscv32Architecture

impl Display for Riscv64Architecture

impl Display for SectionIndex

impl Display for Sequence

impl Display for SequencesHeaderParseError

impl Display for SerializeError

impl Display for SourceLoc

impl Display for StorageType

impl Display for StoreId

impl Display for StructCheckContext

impl Display for SubType

impl Display for SymbolIndex

impl Display for TableType

impl Display for TagType

impl Display for TrapCode

impl Display for Triple

impl Display for TryGetError

impl Display for TryReserveError

impl Display for TupleStructCheckContext

impl Display for Type

impl Display for UnnamedEnumVariantCheckContext

impl Display for UnpackedIndex

impl Display for Utf8Error

impl Display for Utf8Error

impl Display for ValType

impl Display for Vendor

impl Display for WasmError

impl Display for X86_32Architecture

impl Display for char_be

impl Display for char_le

impl Display for char_ube

impl Display for char_ule

impl Display for dyn Expected + '_

impl Display for f32_be

impl Display for f32_le

impl Display for f32_ube

impl Display for f32_ule

impl Display for f64_be

impl Display for f64_le

impl Display for f64_ube

impl Display for f64_ule

impl Display for i16_be

impl Display for i16_le

impl Display for i16_ube

impl Display for i16_ule

impl Display for i32_be

impl Display for i32_le

impl Display for i32_ube

impl Display for i32_ule

impl Display for i64_be

impl Display for i64_le

impl Display for i64_ube

impl Display for i64_ule

impl Display for i128_be

impl Display for i128_le

impl Display for i128_ube

impl Display for i128_ule

impl Display for u16_be

impl Display for u16_le

impl Display for u16_ube

impl Display for u16_ule

impl Display for u32_be

impl Display for u32_le

impl Display for u32_ube

impl Display for u32_ule

impl Display for u64_be

impl Display for u64_le

impl Display for u64_ube

impl Display for u64_ule

impl Display for u128_be

impl Display for u128_le

impl Display for u128_ube

impl Display for u128_ule

impl<'a> Display for Unexpected<'a>

impl<'a> Display for wasmer_compiler::lib::std::str::EscapeDebug<'a>

impl<'a> Display for wasmer_compiler::lib::std::str::EscapeDefault<'a>

impl<'a> Display for wasmer_compiler::lib::std::str::EscapeUnicode<'a>

impl<'a> Display for EscapeAscii<'a>

impl<'a> Display for BytesOrWideString<'a>

impl<'a> Display for Demangle<'a>

impl<'a> Display for SymbolName<'a>

impl<'a, K, V> Display for wasmer_compiler::lib::std::collections::hash_map::OccupiedError<'a, K, V>

where K: Debug, V: Debug,

impl<'a, K, V, A> Display for wasmer_compiler::lib::std::collections::btree_map::OccupiedError<'a, K, V, A>

where K: Debug + Ord, V: Debug, A: Allocator + Clone,

impl<'a, K, V, S, A> Display for OccupiedError<'a, K, V, S, A>

where K: Debug, V: Debug, A: Allocator,

impl<'a, K, V, T> Display for MappedRef<'a, K, V, T>

where K: Eq + Hash, T: Display,

impl<'a, R, G, T> Display for MappedReentrantMutexGuard<'a, R, G, T>

where R: RawMutex + 'a, G: GetThreadId + 'a, T: Display + 'a + ?Sized,

impl<'a, R, G, T> Display for ReentrantMutexGuard<'a, R, G, T>

where R: RawMutex + 'a, G: GetThreadId + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for MappedMutexGuard<'a, R, T>

where R: RawMutex + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for MappedRwLockReadGuard<'a, R, T>

where R: RawRwLock + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for MappedRwLockWriteGuard<'a, R, T>

where R: RawRwLock + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for MutexGuard<'a, R, T>

where R: RawMutex + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for RwLockReadGuard<'a, R, T>

where R: RawRwLock + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for RwLockUpgradableReadGuard<'a, R, T>

where R: RawRwLockUpgrade + 'a, T: Display + 'a + ?Sized,

impl<'a, R, T> Display for RwLockWriteGuard<'a, R, T>

where R: RawRwLock + 'a, T: Display + 'a + ?Sized,

impl<A, S, V> Display for ConvertError<A, S, V>

where A: Display, S: Display, V: Display,

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>

where B: Display + ToOwned + ?Sized, <B as ToOwned>::Owned: Display,

impl<E> Display for Report<E>

where E: Error,

impl<F> Display for FromFn<F>

where F: Fn(&mut Formatter<'_>) -> Result<(), Error>,

impl<K, V, S, A> Display for OccupiedError<'_, K, V, S, A>

where K: Debug, V: Debug, A: Allocator,

impl<O> Display for F32<O>

where O: ByteOrder,

impl<O> Display for F64<O>

where O: ByteOrder,

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<Src, Dst> Display for AlignmentError<Src, Dst>

where Src: Deref, Dst: KnownLayout + ?Sized,

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>

where Src: Deref, Dst: KnownLayout + ?Sized,

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>

where Dst: KnownLayout + TryFromBytes + ?Sized,

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<T> Display for TryLockError<T>

impl<T> Display for SendTimeoutError<T>

impl<T> Display for TrySendError<T>

impl<T> Display for &T

where T: Display + ?Sized,

impl<T> Display for &mut T

where T: Display + ?Sized,

impl<T> Display for ThinBox<T>

where T: Display + ?Sized,

impl<T> Display for SendError<T>

impl<T> Display for wasmer_compiler::lib::std::sync::MappedMutexGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for wasmer_compiler::lib::std::sync::MappedRwLockReadGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for wasmer_compiler::lib::std::sync::MappedRwLockWriteGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for wasmer_compiler::lib::std::sync::MutexGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for PoisonError<T>

impl<T> Display for ReentrantLockGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for wasmer_compiler::lib::std::sync::RwLockReadGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for wasmer_compiler::lib::std::sync::RwLockWriteGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for core::cell::Ref<'_, T>

where T: Display + ?Sized,

impl<T> Display for RefMut<'_, T>

where T: Display + ?Sized,

impl<T> Display for NonZero<T>

where T: ZeroablePrimitive + Display,

impl<T> Display for Saturating<T>

where T: Display,

impl<T> Display for Wrapping<T>

where T: Display,

impl<T> Display for ArchivedBox<T>

where T: ArchivePointee + Display + ?Sized,

impl<T> Display for CachePadded<T>

where T: Display,

impl<T> Display for EnumSet<T>

where T: EnumSetType + Display,

impl<T> Display for InvalidEnumDiscriminantError<T>

where T: Display,

impl<T> Display for ShardedLockReadGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for ShardedLockWriteGuard<'_, T>

where T: Display + ?Sized,

impl<T> Display for Unalign<T>

where T: Unaligned + Display,

impl<T, A> Display for Box<T, A>

where T: Display + ?Sized, A: Allocator,

impl<T, A> Display for Arc<T, A>

where T: Display + ?Sized, A: Allocator,

impl<T, A> Display for Rc<T, A>

where T: Display + ?Sized, A: Allocator,

impl<T, B> Display for Ref<B, T>

where B: ByteSlice, T: FromBytes + Display + KnownLayout + Immutable + ?Sized,

impl<T, F> Display for ArchivedRc<T, F>

where T: ArchivePointee + Display + ?Sized,

impl<W> Display for IntoInnerError<W>

impl<const N: usize> Display for GetManyMutError<N>