1.0.0[][src]Trait boolean_enums::lstd::prelude::v1::From

pub trait From<T> {
    fn from(T) -> Self;
}

Simple and safe type conversions in to Self. It is the reciprocal of Into.

This trait is useful when performing error handling as described by the book and is closely related to the ? operator.

When constructing a function that is capable of failing the return type will generally be of the form Result<T, E>.

The From trait allows for simplification of error handling by providing a means of returning a single error type that encapsulates numerous possible erroneous situations.

This trait is not limited to error handling, rather the general case for this trait would be in any type conversions to have an explicit definition of how they are performed.

Note: this trait must not fail. If the conversion can fail, use TryFrom or a dedicated method which returns an Option<T> or a Result<T, E>.

Generic Implementations

  • From<T> for U implies Into<U>for T
  • from is reflexive, which means that From<T> for T is implemented

Examples

String implements From<&str>:

let string = "hello".to_string();
let other_string = String::from("hello");

assert_eq!(string, other_string);

An example usage for error handling:

use std::fs;
use std::io;
use std::num;

enum CliError {
    IoError(io::Error),
    ParseError(num::ParseIntError),
}

impl From<io::Error> for CliError {
    fn from(error: io::Error) -> Self {
        CliError::IoError(error)
    }
}

impl From<num::ParseIntError> for CliError {
    fn from(error: num::ParseIntError) -> Self {
        CliError::ParseError(error)
    }
}

fn open_and_parse_file(file_name: &str) -> Result<i32, CliError> {
    let mut contents = fs::read_to_string(&file_name)?;
    let num: i32 = contents.trim().parse()?;
    Ok(num)
}

Required methods

fn from(T) -> Self

Performs the conversion.

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Implementations on Foreign Types

impl From<Ipv4Addr> for u32
[src]

fn from(ip: Ipv4Addr) -> u32
[src]

Convert an Ipv4Addr into a host byte order u32.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::new(13, 12, 11, 10);
assert_eq!(0x0d0c0b0au32, u32::from(addr));

impl From<Ipv6Addr> for u128
[src]

impl From<NonZeroU16> for u16
[src]

impl From<u8> for usize
[src]

Converts u8 to usize losslessly.

impl From<i16> for i32
[src]

Converts i16 to i32 losslessly.

impl From<i32> for f64
[src]

Converts i32 to f64 losslessly.

impl From<u8> for u128
[src]

Converts u8 to u128 losslessly.

impl From<NonZeroU128> for u128
[src]

impl From<i32> for i64
[src]

Converts i32 to i64 losslessly.

impl From<i16> for f64
[src]

Converts i16 to f64 losslessly.

impl From<bool> for isize
[src]

Converts a bool to a isize. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(isize::from(true), 1);
assert_eq!(isize::from(false), 0);

impl From<NonZeroU8> for u8
[src]

impl From<u8> for i64
[src]

Converts u8 to i64 losslessly.

impl From<i8> for isize
[src]

Converts i8 to isize losslessly.

impl From<i16> for i128
[src]

Converts i16 to i128 losslessly.

impl From<u64> for u128
[src]

Converts u64 to u128 losslessly.

impl From<u32> for i64
[src]

Converts u32 to i64 losslessly.

impl From<bool> for usize
[src]

Converts a bool to a usize. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(usize::from(true), 1);
assert_eq!(usize::from(false), 0);

impl From<bool> for i16
[src]

Converts a bool to a i16. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i16::from(true), 1);
assert_eq!(i16::from(false), 0);

impl From<i8> for i64
[src]

Converts i8 to i64 losslessly.

impl From<u8> for i32
[src]

Converts u8 to i32 losslessly.

impl From<char> for u32
[src]

fn from(c: char) -> u32
[src]

Converts a char into a u32.

Examples

use std::mem;

fn main() {
    let c = 'c';
    let u = u32::from(c);
    assert!(4 == mem::size_of_val(&u))
}

impl From<i8> for i32
[src]

Converts i8 to i32 losslessly.

impl From<u8> for char
[src]

Maps a byte in 0x00...0xFF to a char whose code point has the same value, in U+0000 to U+00FF.

Unicode is designed such that this effectively decodes bytes with the character encoding that IANA calls ISO-8859-1. This encoding is compatible with ASCII.

Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hyphen), which leaves some "blanks", byte values that are not assigned to any character. ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes.

Note that this is also different from Windows-1252 a.k.a. code page 1252, which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks to punctuation and various Latin characters.

To confuse things further, on the Web ascii, iso-8859-1, and windows-1252 are all aliases for a superset of Windows-1252 that fills the remaining blanks with corresponding C0 and C1 control codes.

fn from(i: u8) -> char
[src]

Converts a u8 into a char.

Examples

use std::mem;

fn main() {
    let u = 32 as u8;
    let c = char::from(u);
    assert!(4 == mem::size_of_val(&c))
}

impl From<bool> for u32
[src]

Converts a bool to a u32. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u32::from(true), 1);
assert_eq!(u32::from(false), 0);

impl From<u8> for f32
[src]

Converts u8 to f32 losslessly.

impl From<u16> for i128
[src]

Converts u16 to i128 losslessly.

impl From<i64> for i128
[src]

Converts i64 to i128 losslessly.

impl From<u8> for u32
[src]

Converts u8 to u32 losslessly.

impl From<u16> for usize
[src]

Converts u16 to usize losslessly.

impl From<i8> for f64
[src]

Converts i8 to f64 losslessly.

impl From<u16> for u64
[src]

Converts u16 to u64 losslessly.

impl From<u8> for f64
[src]

Converts u8 to f64 losslessly.

impl From<NonZeroU64> for u64
[src]

impl From<bool> for u128
[src]

Converts a bool to a u128. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u128::from(true), 1);
assert_eq!(u128::from(false), 0);

impl From<u32> for u64
[src]

Converts u32 to u64 losslessly.

impl From<bool> for i128
[src]

Converts a bool to a i128. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i128::from(true), 1);
assert_eq!(i128::from(false), 0);

impl From<u8> for u64
[src]

Converts u8 to u64 losslessly.

impl From<f32> for f64
[src]

Converts f32 to f64 losslessly.

impl From<i32> for i128
[src]

Converts i32 to i128 losslessly.

impl From<u16> for i32
[src]

Converts u16 to i32 losslessly.

impl From<u64> for i128
[src]

Converts u64 to i128 losslessly.

impl From<bool> for u64
[src]

Converts a bool to a u64. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u64::from(true), 1);
assert_eq!(u64::from(false), 0);

impl From<u32> for i128
[src]

Converts u32 to i128 losslessly.

impl From<i16> for i64
[src]

Converts i16 to i64 losslessly.

impl From<bool> for u16
[src]

Converts a bool to a u16. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u16::from(true), 1);
assert_eq!(u16::from(false), 0);

impl From<bool> for i32
[src]

Converts a bool to a i32. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i32::from(true), 1);
assert_eq!(i32::from(false), 0);

impl From<u8> for u16
[src]

Converts u8 to u16 losslessly.

impl From<bool> for i64
[src]

Converts a bool to a i64. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i64::from(true), 1);
assert_eq!(i64::from(false), 0);

impl From<u16> for f64
[src]

Converts u16 to f64 losslessly.

impl From<i8> for i128
[src]

Converts i8 to i128 losslessly.

impl From<bool> for u8
[src]

Converts a bool to a u8. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(u8::from(true), 1);
assert_eq!(u8::from(false), 0);

impl From<NonZeroUsize> for usize
[src]

impl From<u16> for f32
[src]

Converts u16 to f32 losslessly.

impl From<u16> for i64
[src]

Converts u16 to i64 losslessly.

impl From<u16> for u128
[src]

Converts u16 to u128 losslessly.

impl From<i16> for f32
[src]

Converts i16 to f32 losslessly.

impl From<u8> for i16
[src]

Converts u8 to i16 losslessly.

impl From<i8> for f32
[src]

Converts i8 to f32 losslessly.

impl From<bool> for i8
[src]

Converts a bool to a i8. The resulting value is 0 for false and 1 for true values.

Examples

assert_eq!(i8::from(true), 1);
assert_eq!(i8::from(false), 0);

impl From<u8> for i128
[src]

Converts u8 to i128 losslessly.

impl From<NonZeroU32> for u32
[src]

impl From<i16> for isize
[src]

Converts i16 to isize losslessly.

impl From<u32> for u128
[src]

Converts u32 to u128 losslessly.

impl From<u32> for f64
[src]

Converts u32 to f64 losslessly.

impl From<u8> for isize
[src]

Converts u8 to isize losslessly.

impl From<u16> for u32
[src]

Converts u16 to u32 losslessly.

impl From<i8> for i16
[src]

Converts i8 to i16 losslessly.

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Implementors

impl From<RecvError> for RecvTimeoutError
[src]

impl From<CString> for Rc<CStr>
[src]

fn from(s: CString) -> Rc<CStr>
[src]

Converts a CString into a Rc<CStr> without copying or allocating.

impl From<OsString> for Rc<OsStr>
[src]

fn from(s: OsString) -> Rc<OsStr>
[src]

Converts a OsString into a Rc<OsStr> without copying or allocating.

impl From<NulError> for Error
[src]

fn from(NulError) -> Error
[src]

Converts a NulError into a io::Error.

impl From<RecvError> for TryRecvError
[src]

impl From<DefaultEnvKey> for OsString
[src]

impl From<PathBuf> for OsString
[src]

fn from(path_buf: PathBuf) -> OsString
[src]

Converts a PathBuf into a OsString

This conversion does not allocate or copy memory.

impl From<OsString> for Arc<OsStr>
[src]

fn from(s: OsString) -> Arc<OsStr>
[src]

Converts a OsString into a Arc<OsStr> without copying or allocating.

impl From<PathBuf> for Rc<Path>
[src]

fn from(s: PathBuf) -> Rc<Path>
[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl From<CString> for Arc<CStr>
[src]

fn from(s: CString) -> Arc<CStr>
[src]

Converts a CString into a Arc<CStr> without copying or allocating.

impl From<ChildStderr> for Stdio
[src]

fn from(child: ChildStderr) -> Stdio
[src]

Converts a ChildStderr into a Stdio

Examples

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .arg("non_existing_file.txt")
    .stderr(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let cat = Command::new("cat")
    .arg("-")
    .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

assert_eq!(
    String::from_utf8_lossy(&cat.stdout),
    "rev: cannot open non_existing_file.txt: No such file or directory\n"
);

impl From<ChildStdin> for Stdio
[src]

fn from(child: ChildStdin) -> Stdio
[src]

Converts a ChildStdin into a Stdio

Examples

ChildStdin will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .stdin(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let _echo = Command::new("echo")
    .arg("Hello, world!")
    .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

// "!dlrow ,olleH" echoed to console

impl From<ErrorKind> for Error
[src]

Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.

fn from(kind: ErrorKind) -> Error
[src]

Converts an ErrorKind into an Error.

This conversion allocates a new error with a simple representation of error kind.

Examples

use std::io::{Error, ErrorKind};

let not_found = ErrorKind::NotFound;
let error = Error::from(not_found);
assert_eq!("entity not found", format!("{}", error));

impl From<File> for Stdio
[src]

fn from(file: File) -> Stdio
[src]

Converts a File into a Stdio

Examples

File will be converted to Stdio using Stdio::from under the hood.

use std::fs::File;
use std::process::Command;

// With the `foo.txt` file containing `Hello, world!"
let file = File::open("foo.txt").unwrap();

let reverse = Command::new("rev")
    .stdin(file)  // Implicit File conversion into a Stdio
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH");

impl From<OsString> for PathBuf
[src]

fn from(s: OsString) -> PathBuf
[src]

Converts a OsString into a PathBuf

This conversion does not allocate or copy memory.

impl From<ChildStdout> for Stdio
[src]

fn from(child: ChildStdout) -> Stdio
[src]

Converts a ChildStdout into a Stdio

Examples

ChildStdout will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let hello = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed echo command");

let reverse = Command::new("rev")
    .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");

impl From<PathBuf> for Arc<Path>
[src]

fn from(s: PathBuf) -> Arc<Path>
[src]

Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl From<LocalWaker> for Waker
[src]

fn from(local_waker: LocalWaker) -> Waker
[src]

Converts a LocalWaker into a Waker.

This conversion turns a !Sync LocalWaker into a Sync Waker, allowing a wakeup object to be sent to another thread, but giving up its ability to do specialized thread-local wakeup behavior.

impl From<isize> for AtomicIsize
[src]

fn from(v: isize) -> AtomicIsize
[src]

Converts an isize into an AtomicIsize.

impl From<usize> for AtomicUsize
[src]

fn from(v: usize) -> AtomicUsize
[src]

Converts an usize into an AtomicUsize.

impl From<!> for TryFromIntError
[src]

impl From<bool> for AtomicBool
[src]

fn from(b: bool) -> AtomicBool
[src]

Converts a bool into an AtomicBool.

Examples

use std::sync::atomic::AtomicBool;
let atomic_bool = AtomicBool::from(true);
assert_eq!(format!("{:?}", atomic_bool), "true")

impl From<AllocErr> for CollectionAllocErr
[src]

impl From<LayoutErr> for CollectionAllocErr
[src]

impl From<[u16; 8]> for IpAddr
[src]

fn from(segments: [u16; 8]) -> IpAddr
[src]

Create an IpAddr::V6 from an eight element 16-bit array.

Examples

use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    525u16, 524u16, 523u16, 522u16,
    521u16, 520u16, 519u16, 518u16,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x20d, 0x20c,
        0x20b, 0x20a,
        0x209, 0x208,
        0x207, 0x206
    )),
    addr
);

impl From<[u16; 8]> for Ipv6Addr
[src]

impl From<[u8; 4]> for IpAddr
[src]

fn from(octets: [u8; 4]) -> IpAddr
[src]

Create an IpAddr::V4 from a four element byte array.

Examples

use std::net::{IpAddr, Ipv4Addr};

let addr = IpAddr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(IpAddr::V4(Ipv4Addr::new(13, 12, 11, 10)), addr);

impl From<[u8; 16]> for IpAddr
[src]

fn from(octets: [u8; 16]) -> IpAddr
[src]

Create an IpAddr::V6 from a sixteen element byte array.

Examples

use std::net::{IpAddr, Ipv6Addr};

let addr = IpAddr::from([
    25u8, 24u8, 23u8, 22u8, 21u8, 20u8, 19u8, 18u8,
    17u8, 16u8, 15u8, 14u8, 13u8, 12u8, 11u8, 10u8,
]);
assert_eq!(
    IpAddr::V6(Ipv6Addr::new(
        0x1918, 0x1716,
        0x1514, 0x1312,
        0x1110, 0x0f0e,
        0x0d0c, 0x0b0a
    )),
    addr
);

impl From<[u8; 16]> for Ipv6Addr
[src]

impl From<[u8; 4]> for Ipv4Addr
[src]

fn from(octets: [u8; 4]) -> Ipv4Addr
[src]

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::from([13u8, 12u8, 11u8, 10u8]);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);

impl From<i16> for AtomicI16
[src]

fn from(v: i16) -> AtomicI16
[src]

Converts an i16 into an AtomicI16.

impl From<i32> for AtomicI32
[src]

fn from(v: i32) -> AtomicI32
[src]

Converts an i32 into an AtomicI32.

impl From<i64> for AtomicI64
[src]

fn from(v: i64) -> AtomicI64
[src]

Converts an i64 into an AtomicI64.

impl From<i8> for AtomicI8
[src]

fn from(v: i8) -> AtomicI8
[src]

Converts an i8 into an AtomicI8.

impl From<u128> for Ipv6Addr
[src]

impl From<u16> for AtomicU16
[src]

fn from(v: u16) -> AtomicU16
[src]

Converts an u16 into an AtomicU16.

impl From<u32> for Ipv4Addr
[src]

fn from(ip: u32) -> Ipv4Addr
[src]

Convert a host byte order u32 into an Ipv4Addr.

Examples

use std::net::Ipv4Addr;

let addr = Ipv4Addr::from(0x0d0c0b0au32);
assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);

impl From<u32> for AtomicU32
[src]

fn from(v: u32) -> AtomicU32
[src]

Converts an u32 into an AtomicU32.

impl From<u64> for AtomicU64
[src]

fn from(v: u64) -> AtomicU64
[src]

Converts an u64 into an AtomicU64.

impl From<u8> for AtomicU8
[src]

fn from(v: u8) -> AtomicU8
[src]

Converts an u8 into an AtomicU8.

impl From<CString> for Box<CStr>
[src]

Important traits for Box<W>
fn from(s: CString) -> Box<CStr>
[src]

Converts a CString into a Box<CStr> without copying or allocating.

impl From<CString> for Vec<u8>
[src]

Important traits for Vec<u8>
fn from(s: CString) -> Vec<u8>
[src]

Converts a CString into a Vec<u8>.

The conversion consumes the CString, and removes the terminating NUL byte.

impl From<OsString> for Box<OsStr>
[src]

Important traits for Box<W>
fn from(s: OsString) -> Box<OsStr>
[src]

Converts a OsString into a Box<OsStr> without copying or allocating.

impl From<Ipv4Addr> for IpAddr
[src]

impl From<Ipv6Addr> for IpAddr
[src]

impl From<SocketAddrV4> for SocketAddr
[src]

fn from(sock4: SocketAddrV4) -> SocketAddr
[src]

Converts a [SocketAddrV4] into a [SocketAddr::V4].

impl From<SocketAddrV6> for SocketAddr
[src]

fn from(sock6: SocketAddrV6) -> SocketAddr
[src]

Converts a [SocketAddrV6] into a [SocketAddr::V6].

impl From<PathBuf> for Box<Path>
[src]

Important traits for Box<W>
fn from(p: PathBuf) -> Box<Path>
[src]

Converts a PathBuf into a Box<Path>

This conversion currently should not allocate memory, but this behavior is not guaranteed on all platforms or in all future versions.

impl From<Box<Path>> for PathBuf
[src]

fn from(boxed: Box<Path>) -> PathBuf
[src]

Converts a Box<Path> into a PathBuf

This conversion does not allocate or copy memory.

impl From<Box<CStr>> for CString
[src]

fn from(s: Box<CStr>) -> CString
[src]

Converts a Box<CStr> into a CString without copying or allocating.

impl From<Box<OsStr>> for OsString
[src]

fn from(boxed: Box<OsStr>) -> OsString
[src]

Converts a Box<OsStr> into a OsString without copying or allocating.

impl From<Box<str>> for Box<[u8]>
[src]

Important traits for Box<W>
fn from(s: Box<str>) -> Box<[u8]>
[src]

Converts a Box<str>> into a Box<[u8]>

This conversion does not allocate on the heap and happens in place.

Examples

// create a Box<str> which will be used to create a Box<[u8]>
let boxed: Box<str> = Box::from("hello");
let boxed_str: Box<[u8]> = Box::from(boxed);

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice = Box::from(slice);

assert_eq!(boxed_slice, boxed_str);

impl From<Box<str>> for String
[src]

fn from(s: Box<str>) -> String
[src]

Converts the given boxed str slice to a String. It is notable that the str slice is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2: Box<str> = s1.into_boxed_str();
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

impl From<String> for OsString
[src]

fn from(s: String) -> OsString
[src]

Converts a String into a [OsString].

The conversion copies the data, and includes an allocation on the heap.

impl From<String> for PathBuf
[src]

fn from(s: String) -> PathBuf
[src]

Converts a String into a PathBuf

This conversion does not allocate or copy memory.

impl From<String> for Arc<str>
[src]

impl From<String> for Rc<str>
[src]

impl From<String> for Box<dyn Error + 'static>
[src]

Important traits for Box<W>
fn from(str_err: String) -> Box<dyn Error + 'static>
[src]

Converts a String into a box of dyn [Error].

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<Error>::from(a_string_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl From<String> for Box<str>
[src]

Important traits for Box<W>
fn from(s: String) -> Box<str>
[src]

Converts the given String to a boxed str slice that is owned.

Examples

Basic usage:

let s1: String = String::from("hello world");
let s2: Box<str> = Box::from(s1);
let s3: String = String::from(s2);

assert_eq!("hello world", s3)

impl From<String> for Box<dyn Error + 'static + Sync + Send>
[src]

Important traits for Box<W>
fn from(err: String) -> Box<dyn Error + 'static + Sync + Send>
[src]

Converts a String into a box of dyn [Error] + Send + Sync.

Examples

use std::error::Error;
use std::mem;

let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<Error + Send + Sync>::from(a_string_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl From<String> for Vec<u8>
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Important traits for Vec<u8>
fn from(string: String) -> Vec<u8>
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Converts the given String to a vector Vec that holds values of type u8.

Examples

Basic usage:

let s1 = String::from("hello world");
let v1 = Vec::from(s1);

for b in v1 {
    println!("{}", b);
}

impl<'a> From<&'a OsString> for Cow<'a, OsStr>
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impl<'a> From<&'a PathBuf> for Cow<'a, Path>
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impl<'a> From<&'a Path> for Rc<Path>
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fn from(s: &Path) -> Rc<Path>
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Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl<'a> From<&'a OsStr> for Cow<'a, OsStr>
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impl<'a> From<Cow<'a, CStr>> for CString
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impl<'a> From<Cow<'a, Path>> for PathBuf
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impl<'a> From<&'a CString> for Cow<'a, CStr>
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impl<'a> From<&'a CStr> for CString
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impl<'a> From<&'a Path> for Cow<'a, Path>
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impl<'a> From<CString> for Cow<'a, CStr>
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impl<'a> From<PathBuf> for Cow<'a, Path>
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impl<'a> From<&'a CStr> for Cow<'a, CStr>
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impl<'a> From<&'a CStr> for Rc<CStr>
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impl<'a> From<OsString> for Cow<'a, OsStr>
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impl<'a> From<Cow<'a, OsStr>> for OsString
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impl<'a> From<&'a OsStr> for Arc<OsStr>
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impl<'a> From<&'a OsStr> for Rc<OsStr>
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impl<'a> From<&'a Path> for Arc<Path>
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fn from(s: &Path) -> Arc<Path>
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Converts a Path into a Rc by copying the Path data into a new Rc buffer.

impl<'a> From<&'a CStr> for Arc<CStr>
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impl<'a> From<&'a str> for Arc<str>
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impl<'a> From<&'a str> for Cow<'a, str>
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impl<'a> From<&'a str> for Rc<str>
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impl<'a> From<&'a str> for Box<dyn Error + 'static>
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Important traits for Box<W>
fn from(err: &'a str) -> Box<dyn Error + 'static>
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Converts a str into a box of dyn [Error].

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<Error>::from(a_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'a> From<&'a str> for Box<str>
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Important traits for Box<W>
fn from(s: &'a str) -> Box<str>
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Converts a &str into a Box<str>

This conversion allocates on the heap and performs a copy of s.

Examples

let boxed: Box<str> = Box::from("hello");
println!("{}", boxed);

impl<'a> From<&'a str> for String
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impl<'a> From<&'a str> for Vec<u8>
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impl<'a> From<&'a CStr> for Box<CStr>
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impl<'a> From<&'a OsStr> for Box<OsStr>
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impl<'a> From<&'a Path> for Box<Path>
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impl<'a> From<&'a String> for Cow<'a, str>
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impl<'a> From<Cow<'a, str>> for Box<dyn Error + 'static>
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Important traits for Box<W>
fn from(err: Cow<'a, str>) -> Box<dyn Error + 'static>
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Converts a [Cow] into a box of dyn [Error].

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<Error>::from(a_cow_str_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'a> From<Cow<'a, str>> for String
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impl<'a> From<String> for Cow<'a, str>
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impl<'a, 'b> From<&'b str> for Box<dyn Error + 'a + Sync + Send>
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Important traits for Box<W>
fn from(err: &'b str) -> Box<dyn Error + 'a + Sync + Send>
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Converts a str into a box of dyn [Error] + Send + Sync.

Examples

use std::error::Error;
use std::mem;

let a_str_error = "a str error";
let a_boxed_error = Box::<Error + Send + Sync>::from(a_str_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a + Sync + Send>
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Important traits for Box<W>
fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a + Sync + Send>
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Converts a [Cow] into a box of dyn [Error] + Send + Sync.

Examples

use std::error::Error;
use std::mem;
use std::borrow::Cow;

let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<Error + Send + Sync>::from(a_cow_str_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl<'a, E> From<E> for Box<dyn Error + 'a> where
    E: 'a + Error
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Important traits for Box<W>
fn from(err: E) -> Box<dyn Error + 'a>
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Converts a type of [Error] into a box of dyn [Error].

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {
    fn description(&self) -> &str {
        "Description of an error"
    }
}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))

impl<'a, E> From<E> for Box<dyn Error + 'a + Sync + Send> where
    E: 'a + Error + Send + Sync
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Important traits for Box<W>
fn from(err: E) -> Box<dyn Error + 'a + Sync + Send>
[src]

Converts a type of [Error] + Send + Sync into a box of dyn [Error] + Send + Sync.

Examples

use std::error::Error;
use std::fmt;
use std::mem;

#[derive(Debug)]
struct AnError;

impl fmt::Display for AnError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f , "An error")
    }
}

impl Error for AnError {
    fn description(&self) -> &str {
        "Description of an error"
    }
}

unsafe impl Send for AnError {}

unsafe impl Sync for AnError {}

let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<Error + Send + Sync>::from(an_error);
assert!(
    mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))

impl<'a, T> From<&'a Option<T>> for Option<&'a T>
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impl<'a, T> From<&'a Vec<T>> for Cow<'a, [T]> where
    T: Clone
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impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T>
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impl<'a, T> From<Cow<'a, [T]>> for Vec<T> where
    [T]: ToOwned,
    <[T] as ToOwned>::Owned == Vec<T>, 
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impl<'a, T> From<&'a T> for OsString where
    T: AsRef<OsStr> + ?Sized
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impl<'a, T> From<&'a T> for PathBuf where
    T: AsRef<OsStr> + ?Sized
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impl<'a, T> From<&'a T> for NonNull<T> where
    T: ?Sized
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impl<'a, T> From<&'a mut T> for NonNull<T> where
    T: ?Sized
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impl<'a, T> From<&'a [T]> for Cow<'a, [T]> where
    T: Clone
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impl<'a, T> From<&'a [T]> for Box<[T]> where
    T: Copy
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Important traits for Box<W>
fn from(slice: &'a [T]) -> Box<[T]>
[src]

Converts a &[T] into a Box<[T]>

This conversion allocates on the heap and performs a copy of slice.

Examples

// create a &[u8] which will be used to create a Box<[u8]>
let slice: &[u8] = &[104, 101, 108, 108, 111];
let boxed_slice: Box<[u8]> = Box::from(slice);

println!("{:?}", boxed_slice);

impl<'a, T> From<&'a [T]> for Vec<T> where
    T: Clone
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impl<'a, T> From<&'a [T]> for Rc<[T]> where
    T: Clone
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impl<'a, T> From<&'a [T]> for Arc<[T]> where
    T: Clone
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impl<'a, T> From<&'a mut [T]> for Vec<T> where
    T: Clone
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impl<'a, T> From<Vec<T>> for Cow<'a, [T]> where
    T: Clone
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impl<I> From<(I, u16)> for SocketAddr where
    I: Into<IpAddr>, 
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fn from(pieces: (I, u16)) -> SocketAddr
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Converts a tuple struct (Into<[IpAddr]>, u16) into a [SocketAddr].

This conversion creates a [SocketAddr::V4] for a [IpAddr::V4] and creates a [SocketAddr::V6] for a [IpAddr::V6].

u16 is treated as port of the newly created [SocketAddr].

impl<T> From<T> for RwLock<T>
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fn from(t: T) -> RwLock<T>
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Creates a new instance of an RwLock<T> which is unlocked. This is equivalent to [RwLock::new].

impl<T> From<T> for Mutex<T>
[src]

fn from(t: T) -> Mutex<T>
[src]

Creates a new mutex in an unlocked state ready for use. This is equivalent to [Mutex::new].

impl<T> From<SendError<T>> for TrySendError<T>
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impl<T> From<PoisonError<T>> for TryLockError<T>
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impl<T> From<T> for RefCell<T>
[src]

impl<T> From<T> for Cell<T>
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impl<T> From<T> for Poll<T>
[src]

impl<T> From<*mut T> for AtomicPtr<T>
[src]

impl<T> From<T> for T
[src]

impl<T> From<T> for UnsafeCell<T>
[src]

impl<T> From<Arc<T>> for Waker where
    T: Wake + 'static, 
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impl<T> From<T> for Rc<T>
[src]

impl<T> From<T> for Arc<T>
[src]

impl<T> From<BinaryHeap<T>> for Vec<T>
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impl<T> From<VecDeque<T>> for Vec<T>
[src]

impl<T> From<Box<[T]>> for Vec<T>
[src]

impl<T> From<Box<T>> for Pin<Box<T>> where
    T: ?Sized
[src]

fn from(boxed: Box<T>) -> Pin<Box<T>>
[src]

Converts a Box<T> into a Pin<Box<T>>

This conversion does not allocate on the heap and happens in place.

impl<T> From<Box<T>> for Rc<T> where
    T: ?Sized
[src]

impl<T> From<Box<T>> for Arc<T> where
    T: ?Sized
[src]

impl<T> From<Vec<T>> for Rc<[T]>
[src]

impl<T> From<Vec<T>> for VecDeque<T>
[src]

impl<T> From<Vec<T>> for Arc<[T]>
[src]

impl<T> From<Vec<T>> for BinaryHeap<T> where
    T: Ord
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impl<T> From<Vec<T>> for Box<[T]>
[src]

impl<T> From<T> for Option<T>
[src]

impl<T> From<T> for Box<T>
[src]

Important traits for Box<W>
fn from(t: T) -> Box<T>
[src]

Converts a generic type T into a Box<T>

The conversion allocates on the heap and moves t from the stack into it.

Examples

let x = 5;
let boxed = Box::new(5);

assert_eq!(Box::from(x), boxed);

impl<T> From<Unique<T>> for NonNull<T> where
    T: ?Sized
[src]

impl<W> From<IntoInnerError<W>> for Error
[src]

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