rama::utils::collections::smallvec::alloc::fmt

Trait Display

1.36.0 · Source

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 · Source

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, }),
);

Dyn Compatibility§

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impl Display for AtomicRmwOp

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impl Display for AttrError

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impl Display for Attribute

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Attributes

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for rama::net::address::Authority

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impl Display for Authority

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impl Display for AuthorityRef<'_>

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impl Display for BStr

use jiff::civil::date;

// No fractional seconds:
let dt = date(2024, 6, 15).at(7, 0, 0, 0);
assert_eq!(format!("{dt}"), "2024-06-15T07:00:00");

// With fractional seconds:
let dt = date(2024, 6, 15).at(7, 0, 0, 123_000_000);
assert_eq!(format!("{dt}"), "2024-06-15T07:00:00.123");

§Example: setting the precision

use jiff::civil::date;

let dt = date(2024, 6, 15).at(7, 0, 0, 123_000_000);
assert_eq!(format!("{dt:.6}"), "2024-06-15T07:00:00.123000");
// Precision values greater than 9 are clamped to 9.
assert_eq!(format!("{dt:.300}"), "2024-06-15T07:00:00.123000000");
// A precision of 0 implies the entire fractional
// component is always truncated.
assert_eq!(format!("{dt:.0}"), "2024-06-15T07:00:00");

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impl Display for Datetime

Available on crate feature alloc only.

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impl Display for Datetime

impl Display for Domain

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impl Display for DomainAddress

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impl Display for DomainParseError

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impl Display for DomainRef<'_>

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impl Display for Duration

The format returned by this implementation is not stable and must not be relied upon.

By default this produces an exact, full-precision printout of the duration. For a concise, rounded printout instead, you can use the .N format specifier:

let duration = Duration::new(123456, 789011223);
println!("{duration:.3}");

impl Display for Error

Displays a TOML parse error

§Example

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

Prints the group as a string that should be losslessly convertible back into the same group (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters.

1.29.0 · Source§

impl Display for proc_macro::Group

Prints the group as a string that should be losslessly convertible back into the same group (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters.

This implementation uses constant stack space and heap space proportional to the size of the Hir.

Prints the identifier as a string that should be losslessly convertible back into the same identifier.

1.29.0 · Source§

impl Display for proc_macro::Ident

Prints the identifier as a string that should be losslessly convertible back into the same identifier.

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

impl Display for Key

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for rama::crypto::dep::aws_lc_rs::error::KeyRejected

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impl Display for KeyRejected

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impl Display for KeyUsage

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impl Display for Keywords

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for LanguageIdentifier

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impl Display for LittleEndian

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impl Display for rama::geo::Locale

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impl Display for Locale

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

Available on crate feature display only.

2.3.  The OPENPGPKEY RDATA Presentation Format

   The RDATA Presentation Format, as visible in Zone Files [RFC1035],
   consists of a single OpenPGP Transferable Public Key as defined in
   Section 11.1 of [RFC4880] encoded in base64 as defined in Section 4
   of [RFC4648].

Source §

impl Display for OsLogError

Available on Apple only.

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impl Display for OtelExporterConfigError

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impl Display for Other

impl Display for PatternSetInsertError

Available on crate feature alloc only.

impl Display for proc_macro2::Punct

Prints the punctuation character as a string that should be losslessly convertible back into the same character.

1.29.0 · Source§

impl Display for proc_macro::Punct

Prints the punctuation character as a string that should be losslessly convertible back into the same character.

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impl Display for PushError

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impl Display for rama::net::uri::Query

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impl Display for rama::dns::client::hickory::resolver::net::proto::op::Query

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impl Display for QueryDeserializeError

impl Display for rama::utils::thirdparty::regex::bytes::Regex

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impl Display for rama::utils::thirdparty::regex::Regex

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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 SpecificationError

Available on crate feature alloc only.

assert_eq!(format!("{}", StatusCode::OK), "200 OK");

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impl Display for StatusCode

Formats the status code, including the canonical reason.

§Example

assert_eq!(format!("{}", StatusCode::OK), "200 OK");

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for SubdivisionSuffix

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Substr

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impl Display for Subtag

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Subtag

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

Error requires Display.

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impl Display for Time

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impl Display for Time

Converts a Time into an ISO 8601 compliant string.

§Formatting options supported

std::fmt::Formatter::precision can be set to control the precision of the fractional second component. When not set, the minimum precision required to losslessly render the value is used.

§Example

use jiff::civil::time;

// No fractional seconds:
let t = time(7, 0, 0, 0);
assert_eq!(format!("{t}"), "07:00:00");

// With fractional seconds:
let t = time(7, 0, 0, 123_000_000);
assert_eq!(format!("{t}"), "07:00:00.123");

§Example: setting the precision

use jiff::civil::time;

let t = time(7, 0, 0, 123_000_000);
assert_eq!(format!("{t:.6}"), "07:00:00.123000");
// Precision values greater than 9 are clamped to 9.
assert_eq!(format!("{t:.300}"), "07:00:00.123000000");
// A precision of 0 implies the entire fractional
// component is always truncated.
assert_eq!(format!("{t:.0}"), "07:00:00");

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impl Display for Time

Available on crate feature alloc only.

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impl Display for Time

Available on crate feature alloc only.

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impl Display for rama::net::address::ip::geo::TimeZoneName

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impl Display for TimeoutError

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impl Display for TimeoutExpired

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impl Display for Timestamp

Converts a Timestamp datetime into a RFC 3339 compliant string.

Since a Timestamp never has an offset associated with it and is always in UTC, the string emitted by this trait implementation uses Z for “Zulu” time. The significance of Zulu time is prescribed by RFC 9557 and means that “the time in UTC is known, but the offset to local time is unknown.” If you need to emit an RFC 3339 compliant string with a specific offset, then use [Timestamp::display_with_offset].

§Formatting options supported

std::fmt::Formatter::precision can be set to control the precision of the fractional second component. When not set, the minimum precision required to losslessly render the value is used.

§Example

This shows the default rendering:

use jiff::Timestamp;

// No fractional seconds.
let ts = Timestamp::from_second(1_123_456_789)?;
assert_eq!(format!("{ts}"), "2005-08-07T23:19:49Z");

// With fractional seconds.
let ts = Timestamp::new(1_123_456_789, 123_000_000)?;
assert_eq!(format!("{ts}"), "2005-08-07T23:19:49.123Z");

§Example: setting the precision

use jiff::Timestamp;

let ts = Timestamp::new(1_123_456_789, 123_000_000)?;
assert_eq!(
    format!("{ts:.6}"),
    "2005-08-07T23:19:49.123000Z",
);
// Precision values greater than 9 are clamped to 9.
assert_eq!(
    format!("{ts:.300}"),
    "2005-08-07T23:19:49.123000000Z",
);
// A precision of 0 implies the entire fractional
// component is always truncated.
assert_eq!(
    format!("{ts:.0}"),
    "2005-08-07T23:19:49Z",
);

Prints the token stream as a string that is supposed to be losslessly convertible back into the same token stream (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters and negative numeric literals.

1.15.0 · Source§

impl Display for proc_macro::TokenStream

Prints the token stream as a string that is supposed to be losslessly convertible back into the same token stream (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters and negative numeric literals.

Note: the exact form of the output is subject to change, e.g. there might be changes in the whitespace used between tokens. Therefore, you should not do any kind of simple substring matching on the output string (as produced by to_string) to implement a proc macro, because that matching might stop working if such changes happen. Instead, you should work at the TokenTree level, e.g. matching against TokenTree::Ident, TokenTree::Punct, or TokenTree::Literal.

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impl Display for proc_macro2::TokenTree

Prints the token tree as a string that is supposed to be losslessly convertible back into the same token tree (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters and negative numeric literals.

1.29.0 · Source§

impl Display for proc_macro::TokenTree

Prints the token tree as a string that is supposed to be losslessly convertible back into the same token tree (modulo spans), except for possibly TokenTree::Groups with Delimiter::None delimiters and negative numeric literals.

Note: the exact form of the output is subject to change, e.g. there might be changes in the whitespace used between tokens. Therefore, you should not do any kind of simple substring matching on the output string (as produced by to_string) to implement a proc macro, because that matching might stop working if such changes happen. Instead, you should work at the TokenTree level, e.g. matching against TokenTree::Ident, TokenTree::Punct, or TokenTree::Literal.

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impl Display for TokioDnsTxtUnsupportedError

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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

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impl Display for TooFewItemsOrOom

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impl Display for TraceId

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impl Display for TransferEncodingDirective

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impl Display for Transform

impl Display for Unauthorized

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impl Display for Undefined

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impl Display for Unicode

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Value

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Value

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

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impl Display for Variants

This trait is implemented for compatibility with fmt!. To create a string, [Writeable::write_to_string] is usually more efficient.

This shows the default rendering:

use jiff::civil::date;

// No fractional seconds:
let zdt = date(2024, 6, 15).at(7, 0, 0, 0).in_tz("US/Eastern")?;
assert_eq!(format!("{zdt}"), "2024-06-15T07:00:00-04:00[US/Eastern]");

// With fractional seconds:
let zdt = date(2024, 6, 15).at(7, 0, 0, 123_000_000).in_tz("US/Eastern")?;
assert_eq!(format!("{zdt}"), "2024-06-15T07:00:00.123-04:00[US/Eastern]");

§Example: setting the precision

use jiff::civil::date;

let zdt = date(2024, 6, 15).at(7, 0, 0, 123_000_000).in_tz("US/Eastern")?;
assert_eq!(
    format!("{zdt:.6}"),
    "2024-06-15T07:00:00.123000-04:00[US/Eastern]",
);
// Precision values greater than 9 are clamped to 9.
assert_eq!(
    format!("{zdt:.300}"),
    "2024-06-15T07:00:00.123000000-04:00[US/Eastern]",
);
// A precision of 0 implies the entire fractional
// component is always truncated.
assert_eq!(
    format!("{zdt:.0}"),
    "2024-06-15T07:00:00-04:00[US/Eastern]",
);

impl<I, C> Display for TreeErrorContext<I, C>
where I: Display, C: Display,

Available on crate feature std only.

The Display implementation allows the std::error::Error implementation

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impl Display for rama::crypto::dep::x509_parser::prelude::asn1_rs::nom::error::Error
where I: Display,

The Display implementation allows the std::error::Error implementation

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impl Display for ExactlyOneError
where I: Iterator,

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impl Display for ExactlyOneError
where I: Iterator,

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impl Display for InputError
where I: Clone + Display,

The Display implementation allows the std::error::Error implementation

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impl Display for InputError
where I: Clone + Display,

The Display implementation allows the std::error::Error implementation

impl Display for VerboseError
where I: Display,

Available on crate feature alloc only.

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impl<T> Display for CreationError<T>

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Display

Trait Display Copy item path

§Completeness and parseability

§Internationalization

§Examples

Required Methods§

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

§Errors

§Examples

Dyn Compatibility§

Implementors§

impl Display for !

impl Display for A

impl Display for AAAA

impl Display for ANAME

impl Display for ASN1DateTime

impl Display for ASN1Error

impl Display for ASN1Time

impl Display for Aarch64Architecture

impl Display for AbiParam

impl Display for rama::layer::abort::Aborted

impl Display for rama::futures::prelude::future::Aborted

impl Display for AccessError

impl Display for AcquireError

impl Display for core::net::parser::AddrParseError

impl Display for rama::net::address::ip::ipnet::AddrParseError

impl Display for AddrParseError

impl Display for rama::crypto::pki_types::AddrParseError

impl Display for AddressType

impl Display for Addresses

impl Display for Aggregation

impl Display for AkamaiH2

impl Display for AkamaiH2ComputeError

impl Display for Algorithm

impl Display for AliasRegion

impl Display for AllocErr

impl Display for rama::utils::collections::smallvec::alloc::alloc::AllocError

impl Display for AllocError

impl Display for Allocation

impl Display for AllowlistSource

impl Display for Alpn

impl Display for AmbiguousError

impl Display for AnyDelimiterCodecError

impl Display for AnyEntity

impl Display for ApplicationProtocol

impl Display for ArcStr

impl Display for Architecture

impl Display for ArgumentPurpose

impl Display for Arguments<'_>

impl Display for ArmArchitecture

impl Display for Array

impl Display for ArrayType

impl Display for ArrayType

impl Display for AsciiChar

impl Display for Asn

impl Display for Asn1GeneralizedTimeRef

impl Display for Asn1ObjectRef

impl Display for Asn1TimeRef

impl Display for Ast

impl Display for AtomicRmwOp

impl Display for AttrError

impl Display for Attribute

impl Display for Attributes

impl Display for rama::net::address::Authority

impl Display for Authority

impl Display for AuthorityRef<'_>

impl Display for BStr

impl Display for Backtrace

impl Display for BadName

impl Display for Baggage

impl Display for BaggageMetadata

impl Display for Basic

impl Display for Bearer

impl Display for rand::distr::bernoulli::BernoulliError

impl Display for BernoulliError

impl Display for BigEndian

impl Display for BigInt

impl Display for BigNum

impl Display for BigNumRef

impl Display for BigUint

Trait Display