Trait bevy_internal::utils::smallvec::alloc::str::FromStr

1.0.0 · source ·
pub trait FromStr: Sized {
    type Err;

    // Required method
    fn from_str(s: &str) -> Result<Self, Self::Err>;
}
Expand description

Parse a value from a string

FromStr’s from_str method is often used implicitly, through str’s parse method. See parse’s documentation for examples.

FromStr does not have a lifetime parameter, and so you can only parse types that do not contain a lifetime parameter themselves. In other words, you can parse an i32 with FromStr, but not a &i32. You can parse a struct that contains an i32, but not one that contains an &i32.

Examples

Basic implementation of FromStr on an example Point type:

use std::str::FromStr;

#[derive(Debug, PartialEq)]
struct Point {
    x: i32,
    y: i32
}

#[derive(Debug, PartialEq, Eq)]
struct ParsePointError;

impl FromStr for Point {
    type Err = ParsePointError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let (x, y) = s
            .strip_prefix('(')
            .and_then(|s| s.strip_suffix(')'))
            .and_then(|s| s.split_once(','))
            .ok_or(ParsePointError)?;

        let x_fromstr = x.parse::<i32>().map_err(|_| ParsePointError)?;
        let y_fromstr = y.parse::<i32>().map_err(|_| ParsePointError)?;

        Ok(Point { x: x_fromstr, y: y_fromstr })
    }
}

let expected = Ok(Point { x: 1, y: 2 });
// Explicit call
assert_eq!(Point::from_str("(1,2)"), expected);
// Implicit calls, through parse
assert_eq!("(1,2)".parse(), expected);
assert_eq!("(1,2)".parse::<Point>(), expected);
// Invalid input string
assert!(Point::from_str("(1 2)").is_err());

Required Associated Types§

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type Err

The associated error which can be returned from parsing.

Required Methods§

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fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

If parsing succeeds, return the value inside Ok, otherwise when the string is ill-formatted return an error specific to the inside Err. The error type is specific to the implementation of the trait.

Examples

Basic usage with i32, a type that implements FromStr:

use std::str::FromStr;

let s = "5";
let x = i32::from_str(s).unwrap();

assert_eq!(5, x);

Object Safety§

This trait is not object safe.

Implementors§

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impl FromStr for Format

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impl FromStr for CursorIcon

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impl FromStr for log::Level

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impl FromStr for log::LevelFilter

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impl FromStr for Signal

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type Err = Errno

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impl FromStr for Mp4Type

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type Err = String

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impl FromStr for serde_json::value::Value

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type Err = Error

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impl FromStr for AccessQualifier

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type Err = ()

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impl FromStr for AddressingModel

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type Err = ()

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impl FromStr for BuiltIn

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type Err = ()

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impl FromStr for Capability

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type Err = ()

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impl FromStr for CooperativeMatrixLayout

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type Err = ()

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impl FromStr for CooperativeMatrixUse

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type Err = ()

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impl FromStr for Decoration

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type Err = ()

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impl FromStr for Dim

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type Err = ()

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impl FromStr for ExecutionMode

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type Err = ()

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impl FromStr for ExecutionModel

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type Err = ()

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impl FromStr for FPDenormMode

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type Err = ()

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impl FromStr for FPOperationMode

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type Err = ()

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impl FromStr for FPRoundingMode

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type Err = ()

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impl FromStr for FunctionParameterAttribute

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type Err = ()

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impl FromStr for GroupOperation

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type Err = ()

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impl FromStr for HostAccessQualifier

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type Err = ()

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impl FromStr for ImageChannelDataType

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type Err = ()

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impl FromStr for ImageChannelOrder

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type Err = ()

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impl FromStr for ImageFormat

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type Err = ()

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impl FromStr for InitializationModeQualifier

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type Err = ()

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impl FromStr for KernelEnqueueFlags

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type Err = ()

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impl FromStr for LinkageType

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type Err = ()

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impl FromStr for LoadCacheControl

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type Err = ()

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impl FromStr for MemoryModel

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type Err = ()

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impl FromStr for OverflowModes

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type Err = ()

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impl FromStr for PackedVectorFormat

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type Err = ()

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impl FromStr for QuantizationModes

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type Err = ()

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impl FromStr for RayQueryCandidateIntersectionType

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type Err = ()

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impl FromStr for RayQueryCommittedIntersectionType

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type Err = ()

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impl FromStr for RayQueryIntersection

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type Err = ()

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impl FromStr for SamplerAddressingMode

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type Err = ()

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impl FromStr for SamplerFilterMode

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type Err = ()

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impl FromStr for Scope

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type Err = ()

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impl FromStr for SourceLanguage

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type Err = ()

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impl FromStr for StorageClass

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type Err = ()

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impl FromStr for StoreCacheControl

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type Err = ()

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impl FromStr for Color

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impl FromStr for ColorChoice

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impl FromStr for bevy_internal::scene::ron::Value

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impl FromStr for IpAddr

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impl FromStr for SocketAddr

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impl FromStr for bool

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impl FromStr for char

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impl FromStr for f32

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impl FromStr for f64

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impl FromStr for i8

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impl FromStr for i16

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impl FromStr for i32

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impl FromStr for i64

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impl FromStr for i128

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impl FromStr for isize

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impl FromStr for u8

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impl FromStr for u16

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impl FromStr for u32

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impl FromStr for u64

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impl FromStr for u128

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impl FromStr for usize

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impl FromStr for Addr

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type Err = Box<dyn Error>

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impl FromStr for Hash

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impl FromStr for ColorArg

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type Err = &'static str

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impl FromStr for Pattern

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type Err = Error

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impl FromStr for regex::regex::bytes::Regex

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type Err = Error

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impl FromStr for regex::regex::string::Regex

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type Err = Error

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impl FromStr for Number

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type Err = Error

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impl FromStr for SmolStr

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impl FromStr for Directive

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impl FromStr for Targets

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impl FromStr for EnvFilter

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impl FromStr for NonMaxI8

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impl FromStr for NonMaxI16

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impl FromStr for NonMaxI32

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impl FromStr for NonMaxI64

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impl FromStr for NonMaxI128

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impl FromStr for NonMaxIsize

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impl FromStr for NonMaxU8

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impl FromStr for NonMaxU16

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impl FromStr for NonMaxU32

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impl FromStr for NonMaxU64

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impl FromStr for NonMaxU128

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impl FromStr for NonMaxUsize

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impl FromStr for Uuid

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type Err = Error

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impl FromStr for bevy_internal::utils::tracing::metadata::LevelFilter

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impl FromStr for bevy_internal::utils::tracing::Level

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impl FromStr for String

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impl FromStr for Ipv4Addr

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impl FromStr for Ipv6Addr

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impl FromStr for SocketAddrV4

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impl FromStr for SocketAddrV6

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impl FromStr for NonZeroI8

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impl FromStr for NonZeroI16

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impl FromStr for NonZeroI32

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impl FromStr for NonZeroI64

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impl FromStr for NonZeroI128

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impl FromStr for NonZeroIsize

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impl FromStr for NonZeroU8

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impl FromStr for NonZeroU16

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impl FromStr for NonZeroU32

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impl FromStr for NonZeroU64

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impl FromStr for NonZeroU128

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impl FromStr for NonZeroUsize

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impl FromStr for OsString

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impl FromStr for PathBuf

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impl<const CAP: usize> FromStr for ArrayString<CAP>