Trait nom::lib::std::convert::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::io::{self, Read};
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 file = std::fs::File::open("test")?;
    let mut contents = String::new();
    file.read_to_string(&mut contents)?;
    let num: i32 = contents.trim().parse()?;
    Ok(num)
}

Required Methods

fn from(T) -> Self

Performs the conversion.

Implementations on Foreign Types

impl From<Ipv4Addr> for u32

fn from(ip: Ipv4Addr) -> u32

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<[u16; 8]> for Ipv6Addr

fn from(segments: [u16; 8]) -> Ipv6Addr

impl From<PathBuf> for Rc<Path>

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

impl From<OsString> for Rc<OsStr>

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

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

impl<'a, T> From<&'a T> for OsString where     T: AsRef<OsStr> + ?Sized,

fn from(s: &'a T) -> OsString

impl From<CString> for Arc<CStr>

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

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

impl From<[u16; 8]> for IpAddr

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

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<'a> From<&'a OsString> for Cow<'a, OsStr>

fn from(s: &'a OsString) -> Cow<'a, OsStr>

impl From<DefaultEnvKey> for OsString

fn from(k: DefaultEnvKey) -> OsString

impl From<ChildStderr> for Stdio

fn from(child: ChildStderr) -> Stdio

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<OsString> for PathBuf

fn from(s: OsString) -> PathBuf

impl<T> From<T> for RwLock<T>

fn from(t: T) -> RwLock<T>

Creates a new instance of an RwLock<T> which is unlocked. This is equivalent to [RwLock::new].

impl From<ChildStdin> for Stdio

fn from(child: ChildStdin) -> Stdio

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<[u8; 16]> for IpAddr

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

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<'a> From<&'a Path> for Rc<Path>

fn from(s: &Path) -> Rc<Path>

impl From<PathBuf> for Arc<Path>

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

impl<'a> From<&'a CString> for Cow<'a, CStr>

fn from(s: &'a CString) -> Cow<'a, CStr>

impl<'a> From<&'a CStr> for Arc<CStr>

fn from(s: &CStr) -> Arc<CStr>

impl<'a> From<&'a OsStr> for Cow<'a, OsStr>

fn from(s: &'a OsStr) -> Cow<'a, OsStr>

impl<'a> From<&'a CStr> for CString

fn from(s: &'a CStr) -> CString

impl From<u128> for Ipv6Addr

fn from(ip: u128) -> Ipv6Addr

impl From<RecvError> for TryRecvError

fn from(err: RecvError) -> TryRecvError

impl From<RecvError> for RecvTimeoutError

fn from(err: RecvError) -> RecvTimeoutError

impl From<Ipv6Addr> for IpAddr

fn from(ipv6: Ipv6Addr) -> IpAddr

impl From<String> for OsString

fn from(s: String) -> OsString

Converts a [String] into a [OsString].

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

impl<'a> From<PathBuf> for Cow<'a, Path>

fn from(s: PathBuf) -> Cow<'a, Path>

impl<W> From<IntoInnerError<W>> for Error

fn from(iie: IntoInnerError<W>) -> Error

impl From<u32> for Ipv4Addr

fn from(ip: u32) -> Ipv4Addr

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<'a> From<&'a Path> for Arc<Path>

fn from(s: &Path) -> Arc<Path>

impl From<OsString> for Arc<OsStr>

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

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

impl From<Box<Path>> for PathBuf

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

impl From<Ipv4Addr> for IpAddr

fn from(ipv4: Ipv4Addr) -> IpAddr

impl From<[u8; 4]> for Ipv4Addr

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

Examples

use std::net::Ipv4Addr;

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

impl<T> From<T> for Mutex<T>

fn from(t: T) -> Mutex<T>

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

impl<'a> From<Cow<'a, OsStr>> for OsString

fn from(s: Cow<'a, OsStr>) -> OsString

impl<'a> From<&'a OsStr> for Rc<OsStr>

fn from(s: &OsStr) -> Rc<OsStr>

impl From<[u8; 4]> for IpAddr

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

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<'a> From<&'a OsStr> for Arc<OsStr>

fn from(s: &OsStr) -> Arc<OsStr>

impl From<Ipv6Addr> for u128

fn from(ip: Ipv6Addr) -> u128

impl From<ErrorKind> for Error

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

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<CString> for Rc<CStr>

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

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

impl From<File> for Stdio

fn from(file: File) -> Stdio

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<'a> From<OsString> for Cow<'a, OsStr>

fn from(s: OsString) -> Cow<'a, OsStr>

impl<'a> From<&'a CStr> for Rc<CStr>

fn from(s: &CStr) -> Rc<CStr>

impl<'a> From<&'a Path> for Cow<'a, Path>

fn from(s: &'a Path) -> Cow<'a, Path>

impl From<Box<OsStr>> for OsString

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

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

impl<'a> From<CString> for Cow<'a, CStr>

fn from(s: CString) -> Cow<'a, CStr>

impl<'a> From<Cow<'a, CStr>> for CString

fn from(s: Cow<'a, CStr>) -> CString

impl From<Box<CStr>> for CString

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

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

impl<'a, T> From<&'a T> for PathBuf where     T: AsRef<OsStr> + ?Sized,

fn from(s: &'a T) -> PathBuf

impl From<SocketAddrV4> for SocketAddr

fn from(sock4: SocketAddrV4) -> SocketAddr

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

impl From<NulError> for Error

fn from(NulError) -> Error

Converts a NulError into a io::Error.

impl<T> From<PoisonError<T>> for TryLockError<T>

fn from(err: PoisonError<T>) -> TryLockError<T>

impl From<[u8; 16]> for Ipv6Addr

fn from(octets: [u8; 16]) -> Ipv6Addr

impl<'a> From<&'a CStr> for Cow<'a, CStr>

fn from(s: &'a CStr) -> Cow<'a, CStr>

impl From<PathBuf> for OsString

fn from(path_buf: PathBuf) -> OsString

impl<'a> From<Cow<'a, Path>> for PathBuf

fn from(p: Cow<'a, Path>) -> PathBuf

impl From<ChildStdout> for Stdio

fn from(child: ChildStdout) -> Stdio

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<SocketAddrV6> for SocketAddr

fn from(sock6: SocketAddrV6) -> SocketAddr

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

impl<'a> From<&'a PathBuf> for Cow<'a, Path>

fn from(p: &'a PathBuf) -> Cow<'a, Path>

impl<T> From<SendError<T>> for TrySendError<T>

fn from(err: SendError<T>) -> TrySendError<T>

impl From<String> for PathBuf

fn from(s: String) -> PathBuf

impl<I> From<(I, u16)> for SocketAddr where     I: Into<IpAddr>,

fn from(pieces: (I, u16)) -> SocketAddr

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<'a, T> From<&'a mut T> for NonNull<T> where     T: ?Sized,

fn from(reference: &'a mut T) -> NonNull<T>

impl From<bool> for AtomicBool

fn from(b: bool) -> AtomicBool

impl From<i32> for AtomicI32

fn from(v: i32) -> AtomicI32

impl From<u64> for i128

Converts u64 to i128 losslessly.

fn from(small: u64) -> i128

impl From<u16> for u64

Converts u16 to u64 losslessly.

fn from(small: u16) -> u64

impl From<i64> for i128

Converts i64 to i128 losslessly.

fn from(small: i64) -> i128

impl From<u8> for u32

Converts u8 to u32 losslessly.

fn from(small: u8) -> u32

impl From<u8> for usize

Converts u8 to usize losslessly.

fn from(small: u8) -> usize

impl From<isize> for AtomicIsize

fn from(v: isize) -> AtomicIsize

impl From<i16> for AtomicI16

fn from(v: i16) -> AtomicI16

impl From<NonZeroUsize> for usize

fn from(nonzero: NonZeroUsize) -> usize

impl From<bool> for i8

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);

fn from(small: bool) -> i8

impl From<i32> for i64

Converts i32 to i64 losslessly.

fn from(small: i32) -> i64

impl From<u8> for f32

Converts u8 to f32 losslessly.

fn from(small: u8) -> f32

impl From<u8> for u16

Converts u8 to u16 losslessly.

fn from(small: u8) -> u16

impl From<i16> for f64

Converts i16 to f64 losslessly.

fn from(small: i16) -> f64

impl<T> From<T> for Cell<T>

fn from(t: T) -> Cell<T>

impl From<i32> for f64

Converts i32 to f64 losslessly.

fn from(small: i32) -> f64

impl<T> From<T> for RefCell<T>

fn from(t: T) -> RefCell<T>

impl From<u16> for u32

Converts u16 to u32 losslessly.

fn from(small: u16) -> u32

impl From<u64> for u128

Converts u64 to u128 losslessly.

fn from(small: u64) -> u128

impl From<bool> for i128

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);

fn from(small: bool) -> i128

impl From<NonZeroU128> for u128

fn from(nonzero: NonZeroU128) -> u128

impl From<LocalWaker> for Waker

fn from(local_waker: LocalWaker) -> Waker

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<T> From<T> for UnsafeCell<T>

fn from(t: T) -> UnsafeCell<T>

impl<T> From<Unique<T>> for NonNull<T> where     T: ?Sized,

fn from(unique: Unique<T>) -> NonNull<T>

impl From<f32> for f64

Converts f32 to f64 losslessly.

fn from(small: f32) -> f64

impl From<u32> for f64

Converts u32 to f64 losslessly.

fn from(small: u32) -> f64

impl From<u16> for f32

Converts u16 to f32 losslessly.

fn from(small: u16) -> f32

impl From<u16> for u128

Converts u16 to u128 losslessly.

fn from(small: u16) -> u128

impl<T> From<T> for Poll<T>

fn from(t: T) -> Poll<T>

impl From<u32> for AtomicU32

fn from(v: u32) -> AtomicU32

impl From<u8> for u64

Converts u8 to u64 losslessly.

fn from(small: u8) -> u64

impl From<u8> for i64

Converts u8 to i64 losslessly.

fn from(small: u8) -> i64

impl From<u16> for i128

Converts u16 to i128 losslessly.

fn from(small: u16) -> i128

impl From<u16> for usize

Converts u16 to usize losslessly.

fn from(small: u16) -> usize

impl From<u16> for i64

Converts u16 to i64 losslessly.

fn from(small: u16) -> i64

impl From<i8> for i128

Converts i8 to i128 losslessly.

fn from(small: i8) -> i128

impl From<i8> for f32

Converts i8 to f32 losslessly.

fn from(small: i8) -> f32

impl From<NonZeroU8> for u8

fn from(nonzero: NonZeroU8) -> u8

impl From<i64> for AtomicI64

fn from(v: i64) -> AtomicI64

impl From<u16> for i32

Converts u16 to i32 losslessly.

fn from(small: u16) -> i32

impl<T> From<*mut T> for AtomicPtr<T>

fn from(p: *mut T) -> AtomicPtr<T>

impl From<i8> for isize

Converts i8 to isize losslessly.

fn from(small: i8) -> isize

impl From<NonZeroU16> for u16

fn from(nonzero: NonZeroU16) -> u16

impl From<u64> for AtomicU64

fn from(v: u64) -> AtomicU64

impl From<i32> for i128

Converts i32 to i128 losslessly.

fn from(small: i32) -> i128

impl From<bool> for usize

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);

fn from(small: bool) -> usize

impl From<bool> for i32

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);

fn from(small: bool) -> i32

impl From<bool> for i64

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);

fn from(small: bool) -> i64

impl From<NonZeroU64> for u64

fn from(nonzero: NonZeroU64) -> u64

impl From<u8> for isize

Converts u8 to isize losslessly.

fn from(small: u8) -> isize

impl From<i16> for i32

Converts i16 to i32 losslessly.

fn from(small: i16) -> i32

impl From<i16> for i128

Converts i16 to i128 losslessly.

fn from(small: i16) -> i128

impl<'a, T> From<&'a T> for NonNull<T> where     T: ?Sized,

fn from(reference: &'a T) -> NonNull<T>

impl From<bool> for u128

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);

fn from(small: bool) -> u128

impl From<u8> for AtomicU8

fn from(v: u8) -> AtomicU8

impl From<u8> for i32

Converts u8 to i32 losslessly.

fn from(small: u8) -> i32

impl From<bool> for u8

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);

fn from(small: bool) -> u8

impl From<i8> for i64

Converts i8 to i64 losslessly.

fn from(small: i8) -> i64

impl From<u32> for i128

Converts u32 to i128 losslessly.

fn from(small: u32) -> i128

impl From<bool> for i16

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);

fn from(small: bool) -> i16

impl From<u8> for i16

Converts u8 to i16 losslessly.

fn from(small: u8) -> i16

impl From<u8> for char

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

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 u16

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);

fn from(small: bool) -> u16

impl From<u32> for u128

Converts u32 to u128 losslessly.

fn from(small: u32) -> u128

impl From<u32> for u64

Converts u32 to u64 losslessly.

fn from(small: u32) -> u64

impl From<char> for u32

fn from(c: char) -> u32

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<usize> for AtomicUsize

fn from(v: usize) -> AtomicUsize

impl From<i16> for f32

Converts i16 to f32 losslessly.

fn from(small: i16) -> f32

impl From<bool> for isize

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);

fn from(small: bool) -> isize

impl From<u16> for f64

Converts u16 to f64 losslessly.

fn from(small: u16) -> f64

impl From<i8> for i16

Converts i8 to i16 losslessly.

fn from(small: i8) -> i16

impl From<!> for TryFromIntError

fn from(never: !) -> TryFromIntError

impl From<NonZeroU32> for u32

fn from(nonzero: NonZeroU32) -> u32

impl From<i16> for isize

Converts i16 to isize losslessly.

fn from(small: i16) -> isize

impl From<i8> for i32

Converts i8 to i32 losslessly.

fn from(small: i8) -> i32

impl From<bool> for u32

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);

fn from(small: bool) -> u32

impl From<i16> for i64

Converts i16 to i64 losslessly.

fn from(small: i16) -> i64

impl From<u16> for AtomicU16

fn from(v: u16) -> AtomicU16

impl From<i8> for f64

Converts i8 to f64 losslessly.

fn from(small: i8) -> f64

impl From<u8> for u128

Converts u8 to u128 losslessly.

fn from(small: u8) -> u128

impl From<u8> for f64

Converts u8 to f64 losslessly.

fn from(small: u8) -> f64

impl From<bool> for u64

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);

fn from(small: bool) -> u64

impl From<u8> for i128

Converts u8 to i128 losslessly.

fn from(small: u8) -> i128

impl From<i8> for AtomicI8

fn from(v: i8) -> AtomicI8

impl From<u32> for i64

Converts u32 to i64 losslessly.

fn from(small: u32) -> i64

impl<'a> From<&'a str> for Cow<'a, str>

fn from(s: &'a str) -> Cow<'a, str>

impl<'a> From<&'a str> for Arc<str>

fn from(v: &str) -> Arc<str>

impl<T> From<T> for Rc<T>

fn from(t: T) -> Rc<T>

impl<T> From<Box<T>> for Pin<Box<T>>

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

impl<'a> From<String> for Cow<'a, str>

fn from(s: String) -> Cow<'a, str>

impl<'a> From<&'a String> for Cow<'a, str>

fn from(s: &'a String) -> Cow<'a, str>

impl<'a, T> From<&'a [T]> for Cow<'a, [T]> where     T: Clone,

fn from(s: &'a [T]) -> Cow<'a, [T]>

impl<'a, T> From<&'a Vec<T>> for Cow<'a, [T]> where     T: Clone,

fn from(v: &'a Vec<T>) -> Cow<'a, [T]>

impl<'a, T> From<&'a [T]> for Rc<[T]> where     T: Clone,

fn from(v: &[T]) -> Rc<[T]>

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

fn from(v: Vec<T>) -> Arc<[T]>

impl<'a, T> From<&'a [T]> for Arc<[T]> where     T: Clone,

fn from(v: &[T]) -> Arc<[T]>

impl<'a> From<&'a str> for Rc<str>

fn from(v: &str) -> Rc<str>

impl<T> From<Box<T>> for Arc<T> where     T: ?Sized,

fn from(v: Box<T>) -> Arc<T>

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

fn from(v: Vec<T>) -> Rc<[T]>

impl From<String> for Rc<str>

fn from(v: String) -> Rc<str>

impl<'a, T> From<Vec<T>> for Cow<'a, [T]> where     T: Clone,

fn from(v: Vec<T>) -> Cow<'a, [T]>

impl From<String> for Arc<str>

fn from(v: String) -> Arc<str>

impl<T> From<Box<T>> for Rc<T> where     T: ?Sized,

fn from(v: Box<T>) -> Rc<T>

impl<T> From<Arc<T>> for Waker where     T: Wake + 'static,

fn from(rc: Arc<T>) -> Waker

impl<T> From<T> for Arc<T>

fn from(t: T) -> Arc<T>

Implementors

impl From<AllocErr> for CollectionAllocErr

fn from(AllocErr) -> CollectionAllocErr

impl From<LayoutErr> for CollectionAllocErr

fn from(LayoutErr) -> CollectionAllocErr

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

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(s: Box<str>) -> Box<[u8]>

impl From<Box<str>> for String

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

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 Box<dyn Error + 'static>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(str_err: String) -> Box<dyn Error + 'static>

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>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

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

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>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: String) -> Box<dyn Error + 'static + Sync + Send>

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>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(string: String) -> Vec<u8>

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 From<CString> for Box<CStr>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

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

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

impl From<CString> for Vec<u8>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: CString) -> Vec<u8>

Converts a CString into a Vec<u8>.

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

impl From<OsString> for Box<OsStr>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(s: OsString) -> Box<OsStr>

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

impl From<PathBuf> for Box<Path>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(p: PathBuf) -> Box<Path>

impl<'a> From<&'a str> for CompleteStr<'a>

fn from(src: &'a str) -> Self

impl<'a> From<&'a str> for Box<dyn Error + 'static>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: &'a str) -> Box<dyn Error + 'static>

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>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(s: &'a str) -> Box<str>

impl<'a> From<&'a str> for String

fn from(s: &'a str) -> String

impl<'a> From<&'a str> for Vec<u8>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: &'a str) -> Vec<u8>

impl<'a> From<&'a CStr> for Box<CStr>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(s: &'a CStr) -> Box<CStr>

impl<'a> From<&'a OsStr> for Box<OsStr>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(s: &'a OsStr) -> Box<OsStr>

impl<'a> From<&'a Path> for Box<Path>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(path: &'a Path) -> Box<Path>

impl<'a> From<Cow<'a, str>> for Box<dyn Error + 'static>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: Cow<'a, str>) -> Box<dyn Error + 'static>

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

fn from(s: Cow<'a, str>) -> String

impl<'a> From<&'a [u8]> for CompleteByteSlice<'a>

fn from(src: &'a [u8]) -> Self

impl<'a, 'b> From<&'b &'a str> for CompleteStr<'a>

fn from(src: &'b &'a str) -> Self

impl<'a, 'b> From<&'b &'a [u8]> for CompleteByteSlice<'a>

fn from(src: &'b &'a [u8]) -> Self

impl<'a, 'b> From<&'b str> for Box<dyn Error + 'a + Sync + Send>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: &'b str) -> Box<dyn Error + 'a + Sync + Send>

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>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: Cow<'b, str>) -> Box<dyn Error + 'a + Sync + Send>

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,

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: E) -> Box<dyn Error + 'a>

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,

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(err: E) -> Box<dyn Error + 'a + Sync + Send>

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>

fn from(o: &'a Option<T>) -> Option<&'a T>

impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T>

fn from(o: &'a mut Option<T>) -> Option<&'a mut T>

impl<'a, T> From<Cow<'a, [T]>> for Vec<T> where     [T]: ToOwned,     <[T] as ToOwned>::Owned == Vec<T>,

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: Cow<'a, [T]>) -> Vec<T>

impl<'a, T> From<&'a [T]> for Box<[T]> where     T: Copy,

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(slice: &'a [T]) -> Box<[T]>

impl<'a, T> From<&'a [T]> for Vec<T> where     T: Clone,

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: &'a [T]) -> Vec<T>

impl<'a, T> From<&'a mut [T]> for Vec<T> where     T: Clone,

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: &'a mut [T]) -> Vec<T>

impl<T> From<T> for T

fn from(t: T) -> T

impl<T> From<BinaryHeap<T>> for Vec<T>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(heap: BinaryHeap<T>) -> Vec<T>

impl<T> From<VecDeque<T>> for Vec<T>

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(other: VecDeque<T>) -> Vec<T>

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

Important traits for Vec<u8>

impl Write for Vec<u8>

fn from(s: Box<[T]>) -> Vec<T>

impl<T> From<Vec<T>> for VecDeque<T>

fn from(other: Vec<T>) -> VecDeque<T>

impl<T> From<Vec<T>> for BinaryHeap<T> where     T: Ord,

fn from(vec: Vec<T>) -> BinaryHeap<T>

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

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(v: Vec<T>) -> Box<[T]>

impl<T> From<T> for Option<T>

fn from(val: T) -> Option<T>

impl<T> From<T> for Box<T>

Important traits for Box<W>

impl<W> Write for Box<W> where
    W: Write + ?Sized, impl<R> Read for Box<R> where
    R: Read + ?Sized, impl<I> Iterator for Box<I> where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn from(t: T) -> Box<T>