//! The `select!` macro.
-/// A simple wrapper around the standard macros.
-///
-/// This is just an ugly workaround until it becomes possible to import macros with `use`
-/// statements.
-///
-/// TODO(stjepang): Once we bump the minimum required Rust version to 1.30 or newer, we should:
-///
-/// 1. Remove all `#[macro_export(local_inner_macros)]` lines.
-/// 2. Replace `crossbeam_channel_delegate` with direct macro invocations.
-#[doc(hidden)]
-#[macro_export]
-macro_rules! crossbeam_channel_delegate {
- (concat($($args:tt)*)) => {
- concat!($($args)*)
- };
- (stringify($($args:tt)*)) => {
- stringify!($($args)*)
- };
- (unreachable($($args:tt)*)) => {
- unreachable!($($args)*)
- };
- (compile_error($($args:tt)*)) => {
- compile_error!($($args)*)
- };
-}
-
/// A helper macro for `select!` to hide the long list of macro patterns from the documentation.
///
/// The macro consists of two stages:
/// If the parsing stage encounters a syntax error or the codegen stage ends up with too many
/// cases to process, the macro fails with a compile-time error.
#[doc(hidden)]
-#[macro_export(local_inner_macros)]
+#[macro_export]
macro_rules! crossbeam_channel_internal {
// The list is empty. Now check the arguments of each processed case.
(@list
()
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($head)*)
()
(default => $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
(default() => $($tail)*)
($($head)*)
(default -> $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected `=>` after `default` case, found `->`"
- ))
+ )
};
// Print an error if there's an `->` after the argument list in the default case.
(@list
(default $args:tt -> $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected `=>` after `default` case, found `->`"
- ))
+ )
};
// Print an error if there is a missing result in a recv case.
(@list
(recv($($args:tt)*) => $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected `->` after `recv` case, found `=>`"
- ))
+ )
};
// Print an error if there is a missing result in a send case.
(@list
(send($($args:tt)*) => $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected `->` after `send` operation, found `=>`"
- ))
+ )
};
// Make sure the arrow and the result are not repeated.
(@list
($case:ident $args:tt -> $res:tt -> $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error("expected `=>`, found `->`"))
+ compile_error!("expected `=>`, found `->`")
};
// Print an error if there is a semicolon after the block.
(@list
($case:ident $args:tt $(-> $res:pat)* => $body:block; $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"did you mean to put a comma instead of the semicolon after `}`?"
- ))
+ )
};
// The first case is separated by a comma.
(@list
($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr, $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
($($tail)*)
($($head)* $case ($($args)*) $(-> $res)* => { $body },)
($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:block $($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
($($tail)*)
($($head)* $case ($($args)*) $(-> $res)* => { $body },)
($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
()
($($head)* $case ($($args)*) $(-> $res)* => { $body },)
($case:ident ($($args:tt)*) $(-> $res:pat)* => $body:expr,)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
()
($($head)* $case ($($args)*) $(-> $res)* => { $body },)
($($tail:tt)*)
($($head:tt)*)
) => {
- crossbeam_channel_internal!(@list_error1 $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error1 $($tail)*)
};
// Stage 1: check the case type.
(@list_error1 recv $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error2 recv $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error2 recv $($tail)*)
};
(@list_error1 send $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error2 send $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error2 send $($tail)*)
};
(@list_error1 default $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error2 default $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error2 default $($tail)*)
};
(@list_error1 $t:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected one of `recv`, `send`, or `default`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
(@list_error1 $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error2 $($tail)*);
+ $crate::crossbeam_channel_internal!(@list_error2 $($tail)*);
};
// Stage 2: check the argument list.
(@list_error2 $case:ident) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"missing argument list after `",
- crossbeam_channel_delegate!(stringify($case)),
+ stringify!($case),
"`",
- ))
- ))
+ )
+ )
};
(@list_error2 $case:ident => $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"missing argument list after `",
- crossbeam_channel_delegate!(stringify($case)),
+ stringify!($case),
"`",
- ))
- ))
+ )
+ )
};
(@list_error2 $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error3 $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error3 $($tail)*)
};
// Stage 3: check the `=>` and what comes after it.
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"missing `=>` after `",
- crossbeam_channel_delegate!(stringify($case)),
+ stringify!($case),
"` case",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* =>) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected expression after `=>`"
- ))
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $body:expr; $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma instead of the semicolon after `",
- crossbeam_channel_delegate!(stringify($body)),
+ stringify!($body),
"`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => recv($($a:tt)*) $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected an expression after `=>`"
- ))
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => send($($a:tt)*) $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected an expression after `=>`"
- ))
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => default($($a:tt)*) $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"expected an expression after `=>`"
- ))
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $f:ident($($a:tt)*) $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma after `",
- crossbeam_channel_delegate!(stringify($f)),
+ stringify!($f),
"(",
- crossbeam_channel_delegate!(stringify($($a)*)),
+ stringify!($($a)*),
")`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $f:ident!($($a:tt)*) $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma after `",
- crossbeam_channel_delegate!(stringify($f)),
+ stringify!($f),
"!(",
- crossbeam_channel_delegate!(stringify($($a)*)),
+ stringify!($($a)*),
")`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $f:ident![$($a:tt)*] $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma after `",
- crossbeam_channel_delegate!(stringify($f)),
+ stringify!($f),
"![",
- crossbeam_channel_delegate!(stringify($($a)*)),
+ stringify!($($a)*),
"]`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $f:ident!{$($a:tt)*} $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma after `",
- crossbeam_channel_delegate!(stringify($f)),
+ stringify!($f),
"!{",
- crossbeam_channel_delegate!(stringify($($a)*)),
+ stringify!($($a)*),
"}`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) $(-> $r:pat)* => $body:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"did you mean to put a comma after `",
- crossbeam_channel_delegate!(stringify($body)),
+ stringify!($body),
"`?",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) -> => $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error("missing pattern after `->`"))
+ compile_error!("missing pattern after `->`")
};
(@list_error3 $case:ident($($args:tt)*) $t:tt $(-> $r:pat)* => $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected `->`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 $case:ident($($args:tt)*) -> $t:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected a pattern, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 recv($($args:tt)*) $t:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected `->`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 send($($args:tt)*) $t:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected `->`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 recv $args:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list after `recv`, found `",
- crossbeam_channel_delegate!(stringify($args)),
+ stringify!($args),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 send $args:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list after `send`, found `",
- crossbeam_channel_delegate!(stringify($args)),
+ stringify!($args),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 default $args:tt $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list or `=>` after `default`, found `",
- crossbeam_channel_delegate!(stringify($args)),
+ stringify!($args),
"`",
- ))
- ))
+ )
+ )
};
(@list_error3 $($tail:tt)*) => {
- crossbeam_channel_internal!(@list_error4 $($tail)*)
+ $crate::crossbeam_channel_internal!(@list_error4 $($tail)*)
};
// Stage 4: fail with a generic error message.
(@list_error4 $($tail:tt)*) => {
- crossbeam_channel_delegate!(compile_error("invalid syntax"))
+ compile_error!("invalid syntax")
};
// Success! All cases were parsed.
$cases:tt
$default:tt
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@init
$cases
$default
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
($($cases)* recv($r) -> $res => $body,)
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
($($cases)* recv($r) -> $res => $body,)
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"invalid argument list in `recv(",
- crossbeam_channel_delegate!(stringify($($args)*)),
+ stringify!($($args)*),
")`",
- ))
- ))
+ )
+ )
};
// Print an error if there is no argument list.
(@case
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list after `recv`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
// Check the format of a send case.
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
($($cases)* send($s, $m) -> $res => $body,)
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
($($cases)* send($s, $m) -> $res => $body,)
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"invalid argument list in `send(",
- crossbeam_channel_delegate!(stringify($($args)*)),
+ stringify!($($args)*),
")`",
- ))
- ))
+ )
+ )
};
// Print an error if there is no argument list.
(@case
($($cases:tt)*)
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list after `send`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
// Check the format of a default case.
$cases:tt
()
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
$cases
$cases:tt
()
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
$cases
$cases:tt
()
) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@case
($($tail)*)
$cases
$cases:tt
($($def:tt)+)
) => {
- crossbeam_channel_delegate!(compile_error(
+ compile_error!(
"there can be only one `default` case in a `select!` block"
- ))
+ )
};
// Print an error if the argument list is invalid.
(@case
$cases:tt
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"invalid argument list in `default(",
- crossbeam_channel_delegate!(stringify($($args)*)),
+ stringify!($($args)*),
")`",
- ))
- ))
+ )
+ )
};
// Print an error if there is an unexpected token after `default`.
(@case
$cases:tt
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected an argument list or `=>` after `default`, found `",
- crossbeam_channel_delegate!(stringify($t)),
+ stringify!($t),
"`",
- ))
- ))
+ )
+ )
};
// The case was not consumed, therefore it must be invalid.
$cases:tt
$default:tt
) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"expected one of `recv`, `send`, or `default`, found `",
- crossbeam_channel_delegate!(stringify($case)),
+ stringify!($case),
"`",
- ))
- ))
+ )
+ )
};
// Optimize `select!` into `try_recv()`.
($($cases:tt)*)
$default:tt
) => {{
- const _LEN: usize = crossbeam_channel_internal!(@count ($($cases)*));
+ const _LEN: usize = $crate::crossbeam_channel_internal!(@count ($($cases)*));
let _handle: &$crate::internal::SelectHandle = &$crate::never::<()>();
#[allow(unused_mut)]
let mut _sel = [(_handle, 0, ::std::ptr::null()); _LEN];
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@add
_sel
($($cases)*)
0
};
(@count ($oper:ident $args:tt -> $res:pat => $body:tt, $($cases:tt)*)) => {
- 1 + crossbeam_channel_internal!(@count ($($cases)*))
+ 1 + $crate::crossbeam_channel_internal!(@count ($($cases)*))
};
// Run blocking selection.
let _oper = $crate::internal::select(&mut $sel);
// Erase the lifetime so that `sel` can be dropped early even without NLL.
- #[allow(unsafe_code)]
unsafe { ::std::mem::transmute(_oper) }
};
- crossbeam_channel_internal! {
+ $crate::crossbeam_channel_internal! {
@complete
$sel
_oper
let _oper = $crate::internal::try_select(&mut $sel);
// Erase the lifetime so that `sel` can be dropped early even without NLL.
- #[allow(unsafe_code)]
unsafe { ::std::mem::transmute(_oper) }
};
$body
}
Some(_oper) => {
- crossbeam_channel_internal! {
+ $crate::crossbeam_channel_internal! {
@complete
$sel
_oper
let _oper = $crate::internal::select_timeout(&mut $sel, $timeout);
// Erase the lifetime so that `sel` can be dropped early even without NLL.
- #[allow(unsafe_code)]
unsafe { ::std::mem::transmute(_oper) }
};
$body
}
::std::option::Option::Some(_oper) => {
- crossbeam_channel_internal! {
+ $crate::crossbeam_channel_internal! {
@complete
$sel
_oper
()
$cases:tt
) => {
- crossbeam_channel_delegate!(compile_error("too many operations in a `select!` block"))
+ compile_error!("too many operations in a `select!` block")
};
// Add a receive operation to `sel`.
(@add
) => {{
match $r {
ref _r => {
- #[allow(unsafe_code)]
let $var: &$crate::Receiver<_> = unsafe {
let _r: &$crate::Receiver<_> = _r;
};
$sel[$i] = ($var, $i, $var as *const $crate::Receiver<_> as *const u8);
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@add
$sel
($($tail)*)
) => {{
match $s {
ref _s => {
- #[allow(unsafe_code)]
let $var: &$crate::Sender<_> = unsafe {
let _s: &$crate::Sender<_> = _s;
};
$sel[$i] = ($var, $i, $var as *const $crate::Sender<_> as *const u8);
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@add
$sel
($($tail)*)
let $res = _res;
$body
} else {
- crossbeam_channel_internal! {
+ $crate::crossbeam_channel_internal! {
@complete
$sel
$oper
let $res = _res;
$body
} else {
- crossbeam_channel_internal! {
+ $crate::crossbeam_channel_internal! {
@complete
$sel
$oper
$oper:ident
()
) => {{
- crossbeam_channel_delegate!(unreachable(
+ unreachable!(
"internal error in crossbeam-channel: invalid case"
- ))
+ )
}};
// Catches a bug within this macro (should not happen).
(@$($tokens:tt)*) => {
- crossbeam_channel_delegate!(compile_error(
- crossbeam_channel_delegate!(concat(
+ compile_error!(
+ concat!(
"internal error in crossbeam-channel: ",
- crossbeam_channel_delegate!(stringify(@$($tokens)*)),
- ))
- ))
+ stringify!(@$($tokens)*),
+ )
+ )
};
// The entry points.
() => {
- crossbeam_channel_delegate!(compile_error("empty `select!` block"))
+ compile_error!("empty `select!` block")
};
($($case:ident $(($($args:tt)*))* => $body:expr $(,)*)*) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
($($case $(($($args)*))* => { $body },)*)
()
)
};
($($tokens:tt)*) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
@list
($($tokens)*)
()
/// The `select` macro is a convenience wrapper around [`Select`]. However, it cannot select over a
/// dynamically created list of channel operations.
///
-/// [`Select`]: struct.Select.html
+/// [`Select`]: super::Select
///
/// # Examples
///
/// Block until a send or a receive operation is selected:
///
/// ```
-/// # #[macro_use]
-/// # extern crate crossbeam_channel;
-/// # fn main() {
-/// use std::thread;
-/// use crossbeam_channel::unbounded;
+/// use crossbeam_channel::{select, unbounded};
///
/// let (s1, r1) = unbounded();
/// let (s2, r2) = unbounded();
/// assert_eq!(r2.recv(), Ok(20));
/// }
/// }
-/// # }
/// ```
///
/// Select from a set of operations without blocking:
///
/// ```
-/// # #[macro_use]
-/// # extern crate crossbeam_channel;
-/// # fn main() {
/// use std::thread;
/// use std::time::Duration;
-/// use crossbeam_channel::unbounded;
+/// use crossbeam_channel::{select, unbounded};
///
/// let (s1, r1) = unbounded();
/// let (s2, r2) = unbounded();
/// recv(r2) -> msg => panic!(),
/// default => println!("not ready"),
/// }
-/// # }
/// ```
///
/// Select over a set of operations with a timeout:
///
/// ```
-/// # #[macro_use]
-/// # extern crate crossbeam_channel;
-/// # fn main() {
/// use std::thread;
/// use std::time::Duration;
-/// use crossbeam_channel::unbounded;
+/// use crossbeam_channel::{select, unbounded};
///
/// let (s1, r1) = unbounded();
/// let (s2, r2) = unbounded();
/// recv(r2) -> msg => panic!(),
/// default(Duration::from_millis(100)) => println!("timed out"),
/// }
-/// # }
/// ```
///
/// Optionally add a receive operation to `select!` using [`never`]:
///
/// ```
-/// # #[macro_use]
-/// # extern crate crossbeam_channel;
-/// # fn main() {
/// use std::thread;
/// use std::time::Duration;
-/// use crossbeam_channel::{never, unbounded};
+/// use crossbeam_channel::{select, never, unbounded};
///
/// let (s1, r1) = unbounded();
/// let (s2, r2) = unbounded();
/// recv(r1) -> msg => panic!(),
/// recv(r2.unwrap_or(&never())) -> msg => assert_eq!(msg, Ok(20)),
/// }
-/// # }
/// ```
///
/// To optionally add a timeout to `select!`, see the [example] for [`never`].
///
-/// [`never`]: fn.never.html
-/// [example]: fn.never.html#examples
-#[macro_export(local_inner_macros)]
+/// [`never`]: super::never
+/// [example]: super::never#examples
+#[macro_export]
macro_rules! select {
($($tokens:tt)*) => {
- crossbeam_channel_internal!(
+ $crate::crossbeam_channel_internal!(
$($tokens)*
)
};
projects / rustc.git / blobdiff