Trait switchboard_utils::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§

1.7.0 · source§

impl FromStr for IpAddr

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impl FromStr for SocketAddr

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impl FromStr for chrono::month::Month

Parsing a str into a Month uses the format %B.

Example

use chrono::Month;

assert_eq!("January".parse::<Month>(), Ok(Month::January));
assert!("any day".parse::<Month>().is_err());

The parsing is case-insensitive.

assert_eq!("fEbruARy".parse::<Month>(), Ok(Month::February));

Only the shortest form (e.g. jan) and the longest form (e.g. january) is accepted.

assert!("septem".parse::<Month>().is_err());
assert!("Augustin".parse::<Month>().is_err());
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impl FromStr for chrono::weekday::Weekday

Parsing a str into a Weekday uses the format %A.

Example

use chrono::Weekday;

assert_eq!("Sunday".parse::<Weekday>(), Ok(Weekday::Sun));
assert!("any day".parse::<Weekday>().is_err());

The parsing is case-insensitive.

assert_eq!("mON".parse::<Weekday>(), Ok(Weekday::Mon));

Only the shortest form (e.g. sun) and the longest form (e.g. sunday) is accepted.

assert!("thurs".parse::<Weekday>().is_err());
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impl FromStr for IpNet

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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 serde_json::value::Value

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type Err = Error

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impl FromStr for SwapMode

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type Err = SbError

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impl FromStr for bool

1.20.0 · source§

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 String

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impl FromStr for Ipv4Addr

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impl FromStr for Ipv6Addr

1.5.0 · source§

impl FromStr for SocketAddrV4

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impl FromStr for SocketAddrV6

1.35.0 · source§

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

1.35.0 · source§

impl FromStr for NonZeroI128

1.35.0 · source§

impl FromStr for NonZeroIsize

1.35.0 · source§

impl FromStr for NonZeroU8

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impl FromStr for NonZeroU16

1.35.0 · source§

impl FromStr for NonZeroU32

1.35.0 · source§

impl FromStr for NonZeroU64

1.35.0 · source§

impl FromStr for NonZeroU128

1.35.0 · source§

impl FromStr for NonZeroUsize

1.54.0 · source§

impl FromStr for proc_macro::Literal

Parse a single literal from its stringified representation.

In order to parse successfully, the input string must not contain anything but the literal token. Specifically, it must not contain whitespace or comments in addition to the literal.

The resulting literal token will have a Span::call_site() span.

NOTE: some errors may cause panics instead of returning LexError. We reserve the right to change these errors into LexErrors later.

1.15.0 · source§

impl FromStr for proc_macro::TokenStream

Attempts to break the string into tokens and parse those tokens into a token stream. May fail for a number of reasons, for example, if the string contains unbalanced delimiters or characters not existing in the language. All tokens in the parsed stream get Span::call_site() spans.

NOTE: some errors may cause panics instead of returning LexError. We reserve the right to change these errors into LexErrors later.

1.45.0 · source§

impl FromStr for OsString

1.32.0 · source§

impl FromStr for PathBuf

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impl FromStr for chrono::datetime::DateTime<FixedOffset>

Accepts a relaxed form of RFC3339. A space or a ‘T’ are acepted as the separator between the date and time parts. Additional spaces are allowed between each component.

All of these examples are equivalent:

"2012-12-12T12:12:12Z".parse::<DateTime<FixedOffset>>()?;
"2012-12-12 12:12:12Z".parse::<DateTime<FixedOffset>>()?;
"2012-  12-12T12:  12:12Z".parse::<DateTime<FixedOffset>>()?;
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impl FromStr for chrono::datetime::DateTime<Local>

Accepts a relaxed form of RFC3339. A space or a ‘T’ are accepted as the separator between the date and time parts.

All of these examples are equivalent:

"2012-12-12T12:12:12Z".parse::<DateTime<Local>>()?;
"2012-12-12 12:12:12Z".parse::<DateTime<Local>>()?;
"2012-12-12 12:12:12+0000".parse::<DateTime<Local>>()?;
"2012-12-12 12:12:12+00:00".parse::<DateTime<Local>>()?;
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impl FromStr for chrono::datetime::DateTime<Utc>

Accepts a relaxed form of RFC3339. A space or a ‘T’ are accepted as the separator between the date and time parts.

All of these examples are equivalent:

"2012-12-12T12:12:12Z".parse::<DateTime<Utc>>()?;
"2012-12-12 12:12:12Z".parse::<DateTime<Utc>>()?;
"2012-12-12 12:12:12+0000".parse::<DateTime<Utc>>()?;
"2012-12-12 12:12:12+00:00".parse::<DateTime<Utc>>()?;
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impl FromStr for NaiveDate

Parsing a str into a NaiveDate uses the same format, %Y-%m-%d, as in Debug and Display.

Example

use chrono::NaiveDate;

let d = NaiveDate::from_ymd_opt(2015, 9, 18).unwrap();
assert_eq!("2015-09-18".parse::<NaiveDate>(), Ok(d));

let d = NaiveDate::from_ymd_opt(12345, 6, 7).unwrap();
assert_eq!("+12345-6-7".parse::<NaiveDate>(), Ok(d));

assert!("foo".parse::<NaiveDate>().is_err());
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impl FromStr for NaiveDateTime

Parsing a str into a NaiveDateTime uses the same format, %Y-%m-%dT%H:%M:%S%.f, as in Debug.

Example

use chrono::{NaiveDateTime, NaiveDate};

let dt = NaiveDate::from_ymd_opt(2015, 9, 18).unwrap().and_hms_opt(23, 56, 4).unwrap();
assert_eq!("2015-09-18T23:56:04".parse::<NaiveDateTime>(), Ok(dt));

let dt = NaiveDate::from_ymd_opt(12345, 6, 7).unwrap().and_hms_milli_opt(7, 59, 59, 1_500).unwrap(); // leap second
assert_eq!("+12345-6-7T7:59:60.5".parse::<NaiveDateTime>(), Ok(dt));

assert!("foo".parse::<NaiveDateTime>().is_err());
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impl FromStr for NaiveTime

Parsing a str into a NaiveTime uses the same format, %H:%M:%S%.f, as in Debug and Display.

Example

use chrono::NaiveTime;

let t = NaiveTime::from_hms_opt(23, 56, 4).unwrap();
assert_eq!("23:56:04".parse::<NaiveTime>(), Ok(t));

let t = NaiveTime::from_hms_nano_opt(23, 56, 4, 12_345_678).unwrap();
assert_eq!("23:56:4.012345678".parse::<NaiveTime>(), Ok(t));

let t = NaiveTime::from_hms_nano_opt(23, 59, 59, 1_234_567_890).unwrap(); // leap second
assert_eq!("23:59:60.23456789".parse::<NaiveTime>(), Ok(t));

// Seconds are optional
let t = NaiveTime::from_hms_opt(23, 56, 0).unwrap();
assert_eq!("23:56".parse::<NaiveTime>(), Ok(t));

assert!("foo".parse::<NaiveTime>().is_err());
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impl FromStr for FixedOffset

Parsing a str into a FixedOffset uses the format %z.

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impl FromStr for HeaderName

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impl FromStr for HeaderValue

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impl FromStr for Method

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impl FromStr for StatusCode

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impl FromStr for Authority

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impl FromStr for PathAndQuery

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impl FromStr for Scheme

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impl FromStr for Uri

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impl FromStr for Ipv4Net

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impl FromStr for Ipv6Net

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impl FromStr for JsonPathInst

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type Err = String

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impl FromStr for Mime

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impl FromStr for BigInt

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impl FromStr for BigUint

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impl FromStr for proc_macro2::Literal

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impl FromStr for proc_macro2::TokenStream

Attempts to break the string into tokens and parse those tokens into a token stream.

May fail for a number of reasons, for example, if the string contains unbalanced delimiters or characters not existing in the language.

NOTE: Some errors may cause panics instead of returning LexError. We reserve the right to change these errors into LexErrors later.

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impl FromStr for BuildMetadata

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type Err = Error

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impl FromStr for Comparator

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type Err = Error

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impl FromStr for Prerelease

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type Err = Error

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impl FromStr for Version

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type Err = Error

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impl FromStr for VersionReq

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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 Url

Parse a string as an URL, without a base URL or encoding override.

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impl FromStr for Uuid

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type Err = Error

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impl FromStr for Decimal

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type Err = Error

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impl FromStr for Algorithm

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type Err = Error

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impl FromStr for BlockId

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type Err = String

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impl FromStr for BlockNumber

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type Err = String

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impl FromStr for Bloom

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type Err = FromHexError

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impl FromStr for BmpString

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type Err = Error

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impl FromStr for Bytes

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type Err = ParseBytesError

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impl FromStr for Cfg

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type Err = ParseError

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impl FromStr for CfgExpr

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type Err = ParseError

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impl FromStr for Chain

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type Err = ParseError

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impl FromStr for DateTime

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type Err = Error

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impl FromStr for Datetime

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type Err = DatetimeParseError

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impl FromStr for DerivationPath

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type Err = Bip32Error

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impl FromStr for Deserializer

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type Err = Error

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impl FromStr for Document

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type Err = TomlError

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impl FromStr for ERCNFT

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type Err = String

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impl FromStr for ERCNFTType

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type Err = ()

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impl FromStr for EthersCrate

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type Err = ParseError

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impl FromStr for H32

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type Err = FromHexError

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impl FromStr for H64

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type Err = FromHexError

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impl FromStr for H128

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type Err = FromHexError

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impl FromStr for H160

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type Err = FromHexError

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impl FromStr for H256

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type Err = FromHexError

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impl FromStr for H264

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type Err = FromHexError

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impl FromStr for H384

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type Err = FromHexError

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impl FromStr for H512

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type Err = FromHexError

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impl FromStr for H520

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type Err = FromHexError

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impl FromStr for H768

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type Err = FromHexError

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impl FromStr for I256

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type Err = ParseI256Error

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impl FromStr for InternalString

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impl FromStr for Item

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type Err = TomlError

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impl FromStr for Key

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type Err = TomlError

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impl FromStr for Level

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type Err = ParseLevelError

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impl FromStr for LevelFilter

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type Err = ParseLevelFilterError

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impl FromStr for Map<String, Value>

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type Err = Error

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impl FromStr for Month

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type Err = InvalidVariant

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impl FromStr for Name

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type Err = InvalidNameError

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impl FromStr for NameOrAddress

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type Err = <H160 as FromStr>::Err

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impl FromStr for NodeClient

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type Err = ProviderError

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impl FromStr for Numeric

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type Err = String

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impl FromStr for ObjectIdentifier

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type Err = Error

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impl FromStr for Opcode

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type Err = ParseError

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impl FromStr for Platform

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type Err = ParseError

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impl FromStr for Provider

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impl FromStr for Regex

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type Err = Error

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impl FromStr for Regex

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type Err = Error

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impl FromStr for Signature

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type Err = SignatureError

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impl FromStr for Source

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type Err = Report

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impl FromStr for TagMode

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type Err = Error

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impl FromStr for U64

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type Err = FromHexError

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impl FromStr for U128

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type Err = FromHexError

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impl FromStr for U256

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type Err = FromHexError

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impl FromStr for U512

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type Err = FromHexError

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impl FromStr for Units

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type Err = ConversionError

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impl FromStr for Utf8PathBuf

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impl FromStr for Value

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type Err = Error

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impl FromStr for Value

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type Err = TomlError

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impl FromStr for ValueDeserializer

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type Err = Error

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impl FromStr for Wallet<SigningKey<Secp256k1>>

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type Err = WalletError

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impl FromStr for Weekday

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type Err = InvalidVariant

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impl FromStr for XPriv

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type Err = Bip32Error

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impl FromStr for XPub

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type Err = Bip32Error

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impl<C> FromStr for NonZeroScalar<C>where C: CurveArithmetic,

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type Err = Error

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impl<C> FromStr for ScalarPrimitive<C>where C: Curve,

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type Err = Error

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impl<C> FromStr for Signature<C>where C: PrimeCurve + CurveArithmetic, <<C as Curve>::FieldBytesSize as Add>::Output: ArrayLength<u8>,

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type Err = Error

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impl<K> FromStr for Enr<K>where K: EnrKey,

Convert a URL-SAFE base64 encoded ENR into an ENR.

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type Err = String

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impl<Size> FromStr for EncodedPoint<Size>where Size: ModulusSize,

Decode a SEC1-encoded point from hexadecimal.

Upper and lower case hexadecimal are both accepted, however mixed case is rejected.

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type Err = Error

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impl<W> FromStr for Mnemonic<W>where W: Wordlist,

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type Err = MnemonicError

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

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impl<const MIN: i8, const MAX: i8> FromStr for RangedI8<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: i16, const MAX: i16> FromStr for RangedI16<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: i32, const MAX: i32> FromStr for RangedI32<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: i64, const MAX: i64> FromStr for RangedI64<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: i128, const MAX: i128> FromStr for RangedI128<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: isize, const MAX: isize> FromStr for RangedIsize<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: u8, const MAX: u8> FromStr for RangedU8<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: u16, const MAX: u16> FromStr for RangedU16<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: u32, const MAX: u32> FromStr for RangedU32<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: u64, const MAX: u64> FromStr for RangedU64<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: u128, const MAX: u128> FromStr for RangedU128<MIN, MAX>

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type Err = ParseIntError

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impl<const MIN: usize, const MAX: usize> FromStr for RangedUsize<MIN, MAX>

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type Err = ParseIntError