Trait std::convert::From 1.0.0[−][src]
pub trait From<T> {
fn from(T) -> Self;
}Expand description
Used to do value-to-value conversions while consuming the input value. It is the reciprocal of
Into.
One should always prefer implementing From over Into
because implementing From automatically provides one with an implementation of Into
thanks to the blanket implementation in the standard library.
Only implement Into when targeting a version prior to Rust 1.41 and converting to a type
outside the current crate.
From was not able to do these types of conversions in earlier versions because of Rust’s
orphaning rules.
See Into for more details.
Prefer using Into over using From when specifying trait bounds on a generic function.
This way, types that directly implement Into can be used as arguments as well.
The From is also very useful when performing error handling. When constructing a function
that is capable of failing, the return type will generally be of the form Result<T, E>.
The From trait simplifies error handling by allowing a function to return a single error type
that encapsulate multiple error types. See the “Examples” section and the book for more
details.
Note: This trait must not fail. If the conversion can fail, use TryFrom.
Generic Implementations
From<T> for UimpliesInto<U> for TFromis reflexive, which means thatFrom<T> for Tis implemented
Examples
String implements From<&str>:
An explicit conversion from a &str to a String is done as follows:
let string = "hello".to_string(); let other_string = String::from("hello"); assert_eq!(string, other_string);Run
While performing error handling it is often useful to implement From for your own error type.
By converting underlying error types to our own custom error type that encapsulates the
underlying error type, we can return a single error type without losing information on the
underlying cause. The ‘?’ operator automatically converts the underlying error type to our
custom error type by calling Into<CliError>::into which is automatically provided when
implementing From. The compiler then infers which implementation of Into should be used.
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) }Run
Required methods
Implementors
fn from(err: &str) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: &str) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(s: &CStr) -> Box<CStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(s: &OsStr) -> Box<OsStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(path: &Path) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(path: &Path) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>Creates a boxed Path from a reference.
This will allocate and clone path to it.
fn from(cow: Cow<'_, CStr>) -> Box<CStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(cow: Cow<'_, OsStr>) -> Box<OsStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(cow: Cow<'_, Path>) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(cow: Cow<'_, Path>) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>Creates a boxed Path from a clone-on-write pointer.
Converting from a Cow::Owned does not clone or allocate.
Intended for use for errors not exposed to the user, where allocating onto the heap (for normal construction via Error::new) is too costly.
Creates 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 );Run
Creates an Ipv6Addr from a sixteen element byte array.
Examples
use std::net::Ipv6Addr; let addr = Ipv6Addr::from([ 25u8, 24u8, 23u8, 22u8, 21u8, 20u8, 19u8, 18u8, 17u8, 16u8, 15u8, 14u8, 13u8, 12u8, 11u8, 10u8, ]); assert_eq!( Ipv6Addr::new( 0x1918, 0x1716, 0x1514, 0x1312, 0x1110, 0x0f0e, 0x0d0c, 0x0b0a ), addr );Run
Creates 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 );Run
Converts an isize into an AtomicIsize.
Maps a byte in 0x00..=0xFF to a char whose code point has the same value, in U+0000..=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.
Converts an usize into an AtomicUsize.
fn from(s: CString) -> Box<CStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(s: CString) -> Box<CStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(s: OsString) -> Box<OsStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(s: OsString) -> Box<OsStr>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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");Run
Converts a SocketAddrV4 into a SocketAddr::V4.
Converts a SocketAddrV6 into a SocketAddr::V6.
Converts NonZeroI8 to NonZeroI16 losslessly.
Converts NonZeroI8 to NonZeroI32 losslessly.
Converts NonZeroI8 to NonZeroI64 losslessly.
Converts NonZeroI8 to NonZeroI128 losslessly.
Converts NonZeroI8 to NonZeroIsize losslessly.
Converts a NonZeroI16 into an i16
Converts NonZeroI16 to NonZeroI32 losslessly.
Converts NonZeroI16 to NonZeroI64 losslessly.
Converts NonZeroI16 to NonZeroI128 losslessly.
Converts NonZeroI16 to NonZeroIsize losslessly.
Converts a NonZeroI32 into an i32
Converts NonZeroI32 to NonZeroI64 losslessly.
Converts NonZeroI32 to NonZeroI128 losslessly.
Converts a NonZeroI64 into an i64
Converts NonZeroI64 to NonZeroI128 losslessly.
Converts a NonZeroI128 into an i128
Converts a NonZeroIsize into an isize
Converts NonZeroU8 to NonZeroI16 losslessly.
Converts NonZeroU8 to NonZeroI32 losslessly.
Converts NonZeroU8 to NonZeroI64 losslessly.
Converts NonZeroU8 to NonZeroI128 losslessly.
Converts NonZeroU8 to NonZeroIsize losslessly.
Converts NonZeroU8 to NonZeroU16 losslessly.
Converts NonZeroU8 to NonZeroU32 losslessly.
Converts NonZeroU8 to NonZeroU64 losslessly.
Converts NonZeroU8 to NonZeroU128 losslessly.
Converts NonZeroU8 to NonZeroUsize losslessly.
Converts a NonZeroU16 into an u16
Converts NonZeroU16 to NonZeroI32 losslessly.
Converts NonZeroU16 to NonZeroI64 losslessly.
Converts NonZeroU16 to NonZeroI128 losslessly.
Converts NonZeroU16 to NonZeroU32 losslessly.
Converts NonZeroU16 to NonZeroU64 losslessly.
Converts NonZeroU16 to NonZeroU128 losslessly.
Converts NonZeroU16 to NonZeroUsize losslessly.
Converts a NonZeroU32 into an u32
Converts NonZeroU32 to NonZeroI64 losslessly.
Converts NonZeroU32 to NonZeroI128 losslessly.
Converts NonZeroU32 to NonZeroU64 losslessly.
Converts NonZeroU32 to NonZeroU128 losslessly.
Converts a NonZeroU64 into an u64
Converts NonZeroU64 to NonZeroI128 losslessly.
Converts NonZeroU64 to NonZeroU128 losslessly.
Converts a NonZeroU128 into an u128
Converts a NonZeroUsize into an usize
fn from(p: PathBuf) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(p: PathBuf) -> Box<Path>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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.
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" );Run
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 consoleRun
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");Run
pub fn from(s: String) -> Box<str, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(s: String) -> Box<str, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(err: String) -> Box<dyn Error + Send + Sync>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: String) -> Box<dyn Error + Send + Sync>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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::<dyn Error + Send + Sync>::from(a_string_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))Run
fn from(str_err: String) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(str_err: String) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>Converts a RecvError into a RecvTimeoutError.
This conversion always returns RecvTimeoutError::Disconnected.
No data is allocated on the heap.
Converts a RecvError into a TryRecvError.
This conversion always returns TryRecvError::Disconnected.
No data is allocated on the heap.
pub fn from(s: &str) -> Box<str, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(s: &str) -> Box<str, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>pub fn from(cow: Cow<'_, str>) -> Box<str, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>pub fn from(cow: Cow<'_, [T]>) -> Box<[T], Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>pub fn from(slice: &[T]) -> Box<[T], Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(slice: &[T]) -> Box<[T], Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>fn from(err: Cow<'a, str>) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: Cow<'a, str>) -> Box<dyn Error>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>Converts a clone-on-write string to an owned
instance of String.
This extracts the owned string, clones the string if it is not already owned.
Example
// If the string is not owned... let cow: Cow<str> = Cow::Borrowed("eggplant"); // It will allocate on the heap and copy the string. let owned: String = String::from(cow); assert_eq!(&owned[..], "eggplant");Run
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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::<dyn Error + Send + Sync>::from(a_cow_str_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))Run
fn from(err: E) -> Box<dyn Error + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: E) -> Box<dyn Error + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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 {} let an_error = AnError; assert!(0 == mem::size_of_val(&an_error)); let a_boxed_error = Box::<dyn Error>::from(an_error); assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))Run
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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 {} 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::<dyn Error + Send + Sync>::from(an_error); assert!( mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))Run
Converts from &Option<T> to Option<&T>.
Examples
Converts an Option<String> into an Option<usize>, preserving the original.
The map method takes the self argument by value, consuming the original,
so this technique uses as_ref to first take an Option to a reference
to the value inside the original.
let s: Option<String> = Some(String::from("Hello, Rustaceans!")); let o: Option<usize> = Option::from(&s).map(|ss: &String| ss.len()); println!("Can still print s: {:?}", s); assert_eq!(o, Some(18));Run
Convert a clone-on-write slice into a vector.
If s already owns a Vec<T>, it will be returned directly.
If s is borrowing a slice, a new Vec<T> will be allocated and
filled by cloning s’s items into it.
Examples
let o: Cow<[i32]> = Cow::Owned(vec![1, 2, 3]); let b: Cow<[i32]> = Cow::Borrowed(&[1, 2, 3]); assert_eq!(Vec::from(o), Vec::from(b));Run
pub fn from(s: Box<str, A>) -> Box<[u8], A>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(s: Box<str, A>) -> Box<[u8], A>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>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);Run
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.
Stability note: This impl does not yet exist, but we are “reserving space” to add it in the future. See rust-lang/rust#64715 for details.
Turn a VecDeque<T> into a Vec<T>.
This never needs to re-allocate, but does need to do O(n) data movement if the circular buffer doesn’t happen to be at the beginning of the allocation.
Examples
use std::collections::VecDeque; // This one is *O*(1). let deque: VecDeque<_> = (1..5).collect(); let ptr = deque.as_slices().0.as_ptr(); let vec = Vec::from(deque); assert_eq!(vec, [1, 2, 3, 4]); assert_eq!(vec.as_ptr(), ptr); // This one needs data rearranging. let mut deque: VecDeque<_> = (1..5).collect(); deque.push_front(9); deque.push_front(8); let ptr = deque.as_slices().1.as_ptr(); let vec = Vec::from(deque); assert_eq!(vec, [8, 9, 1, 2, 3, 4]); assert_eq!(vec.as_ptr(), ptr);Run
Converts a SendError<T> into a TrySendError<T>.
This conversion always returns a TrySendError::Disconnected containing the data in the SendError<T>.
No data is allocated on the heap.
Converts a Vec<T> into a BinaryHeap<T>.
This conversion happens in-place, and has O(n) time complexity.
pub fn from(t: T) -> Box<T, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(t: T) -> Box<T, Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>Creates a new mutex in an unlocked state ready for use.
This is equivalent to Mutex::new.
Creates a new instance of an RwLock<T> which is unlocked.
This is equivalent to RwLock::new.
Converts a Box<T> into a Pin<Box<T>>
This conversion does not allocate on the heap and happens in place.
pub fn from(v: Vec<T, A>) -> Box<[T], A>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(v: Vec<T, A>) -> Box<[T], A>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>pub fn from(array: [T; N]) -> Box<[T], Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]
pub fn from(array: [T; N]) -> Box<[T], Global>ⓘNotable traits for Box<F, A>impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>
[src]impl<F, A> Future for Box<F, A> where
F: Future + Unpin + ?Sized,
A: Allocator + 'static, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
I: Iterator + ?Sized,
A: Allocator, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for Box<R>impl<W: Write + ?Sized> Write for Box<W>