Trait Display

1.0.0 · 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.

§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, }),
);

Trait DisplayCopy item path

§Internationalization

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Display for Reason

impl Display for ExperimentalTarget

impl Display for NetTarget

impl Display for ParseExperimentalTargetError

impl Display for ParseFuncTargetError

impl Display for RouteTarget

impl Display for surrealdb_core::dbs::Action

impl Display for surrealdb_core::err::Error

impl Display for surrealdb_core::iam::entities::Action

impl Display for ConfigKind

impl Display for surrealdb_core::iam::entities::Level

impl Display for ResourceKind

impl Display for Role

impl Display for surrealdb_core::iam::Error

impl Display for MTreeNode

impl Display for RpcError

impl Display for AccessType

impl Display for surrealdb_core::sql::Algorithm

impl Display for Base

impl Display for Constant

impl Display for Data

impl Display for Dir

impl Display for Entry

impl Display for Expression

impl Display for surrealdb_core::sql::Field

impl Display for Filter

impl Display for Function

impl Display for Geometry

impl Display for surrealdb_core::sql::Id

impl Display for Kind

impl Display for surrealdb_core::sql::Literal

impl Display for Mock

impl Display for surrealdb_core::sql::Number

impl Display for Operator

impl Display for surrealdb_core::sql::Output

impl Display for Part

impl Display for Permission

impl Display for Scoring

impl Display for Statement

impl Display for Subquery

impl Display for TableType

impl Display for Tokenizer

impl Display for surrealdb_core::sql::Value

impl Display for With

impl Display for Distance

impl Display for Index

impl Display for VectorType

impl Display for AccessStatement

impl Display for AlterStatement

impl Display for AnalyzeStatement

impl Display for DefineStatement

impl Display for InfoStatement

impl Display for RemoveStatement

impl Display for CharError

impl Display for TokenKind

impl Display for AsciiChar

impl Display for Infallible

impl Display for FromBytesWithNulError

impl Display for IpAddr

impl Display for SocketAddr

impl Display for GetManyMutError

impl Display for VarError

impl Display for std::io::error::ErrorKind

impl Display for RecvTimeoutError

impl Display for std::sync::mpsc::TryRecvError

impl Display for arbitrary::error::Error

impl Display for argon2::algorithm::Algorithm

impl Display for argon2::error::Error

impl Display for async_channel::TryRecvError

impl Display for base64::alphabet::ParseAlphabetError

impl Display for base64::alphabet::ParseAlphabetError

impl Display for base64::decode::DecodeError

Trait Display