| /// Wait on multiple concurrent branches, returning when the **first** branch |
| /// completes, cancelling the remaining branches. |
| /// |
| /// The `select!` macro must be used inside of async functions, closures, and |
| /// blocks. |
| /// |
| /// The `select!` macro accepts one or more branches with the following pattern: |
| /// |
| /// ```text |
| /// <pattern> = <async expression> (, if <precondition>)? => <handler>, |
| /// ``` |
| /// |
| /// Additionally, the `select!` macro may include a single, optional `else` |
| /// branch, which evaluates if none of the other branches match their patterns: |
| /// |
| /// ```text |
| /// else <expression> |
| /// ``` |
| /// |
| /// The macro aggregates all `<async expression>` expressions and runs them |
| /// concurrently on the **current** task. Once the **first** expression |
| /// completes with a value that matches its `<pattern>`, the `select!` macro |
| /// returns the result of evaluating the completed branch's `<handler>` |
| /// expression. |
| /// |
| /// Additionally, each branch may include an optional `if` precondition. This |
| /// precondition is evaluated **before** the `<async expression>`. If the |
| /// precondition returns `false`, the branch is entirely disabled. This |
| /// capability is useful when using `select!` within a loop. |
| /// |
| /// The complete lifecycle of a `select!` expression is as follows: |
| /// |
| /// 1. Evaluate all provded `<precondition>` expressions. If the precondition |
| /// returns `false`, disable the branch for the remainder of the current call |
| /// to `select!`. Re-entering `select!` due to a loop clears the "disabled" |
| /// state. |
| /// 2. Aggregate the `<async expression>`s from each branch, including the |
| /// disabled ones. If the branch is disabled, `<async expression>` is still |
| /// evaluated, but the resulting future is not polled. |
| /// 3. Concurrently await on the results for all remaining `<async expression>`s. |
| /// 4. Once an `<async expression>` returns a value, attempt to apply the value |
| /// to the provided `<pattern>`, if the pattern matches, evaluate `<handler>` |
| /// and return. If the pattern **does not** match, disable the current branch |
| /// and for the remainder of the current call to `select!`. Continue from step 3. |
| /// 5. If **all** branches are disabled, evaluate the `else` expression. If none |
| /// is provided, panic. |
| /// |
| /// # Notes |
| /// |
| /// ### Runtime characteristics |
| /// |
| /// By running all async expressions on the current task, the expressions are |
| /// able to run **concurrently** but not in **parallel**. This means all |
| /// expressions are run on the same thread and if one branch blocks the thread, |
| /// all other expressions will be unable to continue. If parallelism is |
| /// required, spawn each async expression using [`tokio::spawn`] and pass the |
| /// join handle to `select!`. |
| /// |
| /// [`tokio::spawn`]: crate::spawn |
| /// |
| /// ### Avoid racy `if` preconditions |
| /// |
| /// Given that `if` preconditions are used to disable `select!` branches, some |
| /// caution must be used to avoid missing values. |
| /// |
| /// For example, here is **incorrect** usage of `delay` with `if`. The objective |
| /// is to repeatedly run an asynchronous task for up to 50 milliseconds. |
| /// However, there is a potential for the `delay` completion to be missed. |
| /// |
| /// ```no_run |
| /// use tokio::time::{self, Duration}; |
| /// |
| /// async fn some_async_work() { |
| /// // do work |
| /// } |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let mut delay = time::delay_for(Duration::from_millis(50)); |
| /// |
| /// while !delay.is_elapsed() { |
| /// tokio::select! { |
| /// _ = &mut delay, if !delay.is_elapsed() => { |
| /// println!("operation timed out"); |
| /// } |
| /// _ = some_async_work() => { |
| /// println!("operation completed"); |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// In the above example, `delay.is_elapsed()` may return `true` even if |
| /// `delay.poll()` never returned `Ready`. This opens up a potential race |
| /// condition where `delay` expires between the `while !delay.is_elapsed()` |
| /// check and the call to `select!` resulting in the `some_async_work()` call to |
| /// run uninterrupted despite the delay having elapsed. |
| /// |
| /// One way to write the above example without the race would be: |
| /// |
| /// ``` |
| /// use tokio::time::{self, Duration}; |
| /// |
| /// async fn some_async_work() { |
| /// # time::delay_for(Duration::from_millis(10)).await; |
| /// // do work |
| /// } |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let mut delay = time::delay_for(Duration::from_millis(50)); |
| /// |
| /// loop { |
| /// tokio::select! { |
| /// _ = &mut delay => { |
| /// println!("operation timed out"); |
| /// break; |
| /// } |
| /// _ = some_async_work() => { |
| /// println!("operation completed"); |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// ### Fairness |
| /// |
| /// `select!` randomly picks a branch to check first. This provides some level |
| /// of fairness when calling `select!` in a loop with branches that are always |
| /// ready. |
| /// |
| /// # Panics |
| /// |
| /// `select!` panics if all branches are disabled **and** there is no provided |
| /// `else` branch. A branch is disabled when the provided `if` precondition |
| /// returns `false` **or** when the pattern does not match the result of `<async |
| /// expression>. |
| /// |
| /// # Examples |
| /// |
| /// Basic select with two branches. |
| /// |
| /// ``` |
| /// async fn do_stuff_async() { |
| /// // async work |
| /// } |
| /// |
| /// async fn more_async_work() { |
| /// // more here |
| /// } |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// tokio::select! { |
| /// _ = do_stuff_async() => { |
| /// println!("do_stuff_async() completed first") |
| /// } |
| /// _ = more_async_work() => { |
| /// println!("more_async_work() completed first") |
| /// } |
| /// }; |
| /// } |
| /// ``` |
| /// |
| /// Basic stream selecting. |
| /// |
| /// ``` |
| /// use tokio::stream::{self, StreamExt}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let mut stream1 = stream::iter(vec![1, 2, 3]); |
| /// let mut stream2 = stream::iter(vec![4, 5, 6]); |
| /// |
| /// let next = tokio::select! { |
| /// v = stream1.next() => v.unwrap(), |
| /// v = stream2.next() => v.unwrap(), |
| /// }; |
| /// |
| /// assert!(next == 1 || next == 4); |
| /// } |
| /// ``` |
| /// |
| /// Collect the contents of two streams. In this example, we rely on pattern |
| /// matching and the fact that `stream::iter` is "fused", i.e. once the stream |
| /// is complete, all calls to `next()` return `None`. |
| /// |
| /// ``` |
| /// use tokio::stream::{self, StreamExt}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let mut stream1 = stream::iter(vec![1, 2, 3]); |
| /// let mut stream2 = stream::iter(vec![4, 5, 6]); |
| /// |
| /// let mut values = vec![]; |
| /// |
| /// loop { |
| /// tokio::select! { |
| /// Some(v) = stream1.next() => values.push(v), |
| /// Some(v) = stream2.next() => values.push(v), |
| /// else => break, |
| /// } |
| /// } |
| /// |
| /// values.sort(); |
| /// assert_eq!(&[1, 2, 3, 4, 5, 6], &values[..]); |
| /// } |
| /// ``` |
| /// |
| /// Using the same future in multiple `select!` expressions can be done by passing |
| /// a reference to the future. Doing so requires the future to be [`Unpin`]. A |
| /// future can be made [`Unpin`] by either using [`Box::pin`] or stack pinning. |
| /// |
| /// [`Unpin`]: std::marker::Unpin |
| /// [`Box::pin`]: std::boxed::Box::pin |
| /// |
| /// Here, a stream is consumed for at most 1 second. |
| /// |
| /// ``` |
| /// use tokio::stream::{self, StreamExt}; |
| /// use tokio::time::{self, Duration}; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let mut stream = stream::iter(vec![1, 2, 3]); |
| /// let mut delay = time::delay_for(Duration::from_secs(1)); |
| /// |
| /// loop { |
| /// tokio::select! { |
| /// maybe_v = stream.next() => { |
| /// if let Some(v) = maybe_v { |
| /// println!("got = {}", v); |
| /// } else { |
| /// break; |
| /// } |
| /// } |
| /// _ = &mut delay => { |
| /// println!("timeout"); |
| /// break; |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// Joining two values using `select!`. |
| /// |
| /// ``` |
| /// use tokio::sync::oneshot; |
| /// |
| /// #[tokio::main] |
| /// async fn main() { |
| /// let (tx1, mut rx1) = oneshot::channel(); |
| /// let (tx2, mut rx2) = oneshot::channel(); |
| /// |
| /// tokio::spawn(async move { |
| /// tx1.send("first").unwrap(); |
| /// }); |
| /// |
| /// tokio::spawn(async move { |
| /// tx2.send("second").unwrap(); |
| /// }); |
| /// |
| /// let mut a = None; |
| /// let mut b = None; |
| /// |
| /// while a.is_none() || b.is_none() { |
| /// tokio::select! { |
| /// v1 = (&mut rx1), if a.is_none() => a = Some(v1.unwrap()), |
| /// v2 = (&mut rx2), if b.is_none() => b = Some(v2.unwrap()), |
| /// } |
| /// } |
| /// |
| /// let res = (a.unwrap(), b.unwrap()); |
| /// |
| /// assert_eq!(res.0, "first"); |
| /// assert_eq!(res.1, "second"); |
| /// } |
| /// ``` |
| #[macro_export] |
| #[cfg_attr(docsrs, doc(cfg(feature = "macros")))] |
| macro_rules! select { |
| // Uses a declarative macro to do **most** of the work. While it is possible |
| // to implement fully with a declarative macro, a procedural macro is used |
| // to enable improved error messages. |
| // |
| // The macro is structured as a tt-muncher. All branches are processed and |
| // normalized. Once the input is normalized, it is passed to the top-most |
| // rule. When entering the macro, `@{ }` is inserted at the front. This is |
| // used to collect the normalized input. |
| // |
| // The macro only recurses once per branch. This allows using `select!` |
| // without requiring the user to increase the recursion limit. |
| |
| // All input is normalized, now transform. |
| (@ { |
| // One `_` for each branch in the `select!` macro. Passing this to |
| // `count!` converts $skip to an integer. |
| ( $($count:tt)* ) |
| |
| // Normalized select branches. `( $skip )` is a set of `_` characters. |
| // There is one `_` for each select branch **before** this one. Given |
| // that all input futures are stored in a tuple, $skip is useful for |
| // generating a pattern to reference the future for the current branch. |
| // $skip is also used as an argument to `count!`, returning the index of |
| // the current select branch. |
| $( ( $($skip:tt)* ) $bind:pat = $fut:expr, if $c:expr => $handle:expr, )+ |
| |
| // Fallback expression used when all select branches have been disabled. |
| ; $else:expr |
| |
| }) => {{ |
| // Enter a context where stable "function-like" proc macros can be used. |
| // |
| // This module is defined within a scope and should not leak out of this |
| // macro. |
| mod util { |
| // Generate an enum with one variant per select branch |
| $crate::select_priv_declare_output_enum!( ( $($count)* ) ); |
| } |
| |
| // `tokio::macros::support` is a public, but doc(hidden) module |
| // including a re-export of all types needed by this macro. |
| use $crate::macros::support::Future; |
| use $crate::macros::support::Pin; |
| use $crate::macros::support::Poll::{Ready, Pending}; |
| |
| const BRANCHES: u32 = $crate::count!( $($count)* ); |
| |
| let mut disabled: util::Mask = Default::default(); |
| |
| // First, invoke all the pre-conditions. For any that return true, |
| // set the appropriate bit in `disabled`. |
| $( |
| if !$c { |
| let mask = 1 << $crate::count!( $($skip)* ); |
| disabled |= mask; |
| } |
| )* |
| |
| // Create a scope to separate polling from handling the output. This |
| // adds borrow checker flexibility when using the macro. |
| let mut output = { |
| // Safety: Nothing must be moved out of `futures`. This is to |
| // satisfy the requirement of `Pin::new_unchecked` called below. |
| let mut futures = ( $( $fut , )+ ); |
| |
| $crate::macros::support::poll_fn(|cx| { |
| // Track if any branch returns pending. If no branch completes |
| // **or** returns pending, this implies that all branches are |
| // disabled. |
| let mut is_pending = false; |
| |
| // Randomly generate a starting point. This makes `select!` a |
| // bit more fair and avoids always polling the first future. |
| let start = $crate::macros::support::thread_rng_n(BRANCHES); |
| |
| for i in 0..BRANCHES { |
| let branch = (start + i) % BRANCHES; |
| |
| match branch { |
| $( |
| $crate::count!( $($skip)* ) => { |
| // First, if the future has previously been |
| // disabled, do not poll it again. This is done |
| // by checking the associated bit in the |
| // `disabled` bit field. |
| let mask = 1 << branch; |
| |
| if disabled & mask == mask { |
| // The future has been disabled. |
| continue; |
| } |
| |
| // Extract the future for this branch from the |
| // tuple |
| let ( $($skip,)* fut, .. ) = &mut futures; |
| |
| // Safety: future is stored on the stack above |
| // and never moved. |
| let mut fut = unsafe { Pin::new_unchecked(fut) }; |
| |
| // Try polling it |
| let out = match fut.poll(cx) { |
| Ready(out) => out, |
| Pending => { |
| // Track that at least one future is |
| // still pending and continue polling. |
| is_pending = true; |
| continue; |
| } |
| }; |
| |
| // Disable the future from future polling. |
| disabled |= mask; |
| |
| // The future returned a value, check if matches |
| // the specified pattern. |
| #[allow(unused_variables)] |
| match &out { |
| $bind => {} |
| _ => continue, |
| } |
| |
| // The select is complete, return the value |
| return Ready($crate::select_variant!(util::Out, ($($skip)*))(out)); |
| } |
| )* |
| _ => unreachable!("reaching this means there probably is an off by one bug"), |
| } |
| } |
| |
| if is_pending { |
| Pending |
| } else { |
| // All branches have been disabled. |
| Ready(util::Out::Disabled) |
| } |
| }).await |
| }; |
| |
| match output { |
| $( |
| $crate::select_variant!(util::Out, ($($skip)*) ($bind)) => $handle, |
| )* |
| util::Out::Disabled => $else, |
| _ => unreachable!("failed to match bind"), |
| } |
| }}; |
| |
| // ==== Normalize ===== |
| |
| // These rules match a single `select!` branch and normalize it for |
| // processing by the first rule. |
| |
| (@ { $($t:tt)* } ) => { |
| // No `else` branch |
| $crate::select!(@{ $($t)*; unreachable!() }) |
| }; |
| (@ { $($t:tt)* } else => $else:expr $(,)?) => { |
| $crate::select!(@{ $($t)*; $else }) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr, if $c:expr => $h:block, $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if $c => $h, } $($r)*) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr => $h:block, $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if true => $h, } $($r)*) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr, if $c:expr => $h:block $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if $c => $h, } $($r)*) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr => $h:block $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if true => $h, } $($r)*) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr, if $c:expr => $h:expr ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if $c => $h, }) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr => $h:expr ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if true => $h, }) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr, if $c:expr => $h:expr, $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if $c => $h, } $($r)*) |
| }; |
| (@ { ( $($s:tt)* ) $($t:tt)* } $p:pat = $f:expr => $h:expr, $($r:tt)* ) => { |
| $crate::select!(@{ ($($s)* _) $($t)* ($($s)*) $p = $f, if true => $h, } $($r)*) |
| }; |
| |
| // ===== Entry point ===== |
| |
| ( $p:pat = $($t:tt)* ) => { |
| $crate::select!(@{ () } $p = $($t)*) |
| }; |
| () => { |
| compile_error!("select! requires at least one branch.") |
| }; |
| } |
| |
| // And here... we manually list out matches for up to 64 branches... I'm not |
| // happy about it either, but this is how we manage to use a declarative macro! |
| |
| #[macro_export] |
| #[doc(hidden)] |
| macro_rules! count { |
| () => { |
| 0 |
| }; |
| (_) => { |
| 1 |
| }; |
| (_ _) => { |
| 2 |
| }; |
| (_ _ _) => { |
| 3 |
| }; |
| (_ _ _ _) => { |
| 4 |
| }; |
| (_ _ _ _ _) => { |
| 5 |
| }; |
| (_ _ _ _ _ _) => { |
| 6 |
| }; |
| (_ _ _ _ _ _ _) => { |
| 7 |
| }; |
| (_ _ _ _ _ _ _ _) => { |
| 8 |
| }; |
| (_ _ _ _ _ _ _ _ _) => { |
| 9 |
| }; |
| (_ _ _ _ _ _ _ _ _ _) => { |
| 10 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _) => { |
| 11 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _) => { |
| 12 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 13 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 14 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 15 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 16 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 17 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 18 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 19 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 20 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 21 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 22 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 23 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 24 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 25 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 26 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 27 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 28 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 29 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 30 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 31 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 32 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 33 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 34 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 35 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 36 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 37 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 38 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 39 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 40 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 41 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 42 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 43 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 44 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 45 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 46 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 47 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 48 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 49 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 50 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 51 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 52 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 53 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 54 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 55 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 56 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 57 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 58 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 59 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 60 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 61 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 62 |
| }; |
| (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) => { |
| 63 |
| }; |
| } |
| |
| #[macro_export] |
| #[doc(hidden)] |
| macro_rules! select_variant { |
| ($($p:ident)::*, () $($t:tt)*) => { |
| $($p)::*::_0 $($t)* |
| }; |
| ($($p:ident)::*, (_) $($t:tt)*) => { |
| $($p)::*::_1 $($t)* |
| }; |
| ($($p:ident)::*, (_ _) $($t:tt)*) => { |
| $($p)::*::_2 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _) $($t:tt)*) => { |
| $($p)::*::_3 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _) $($t:tt)*) => { |
| $($p)::*::_4 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_5 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_6 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_7 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_8 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_9 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_10 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_11 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_12 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_13 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_14 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_15 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_16 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_17 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_18 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_19 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_20 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_21 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_22 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_23 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_24 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_25 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_26 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_27 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_28 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_29 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_30 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_31 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_32 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_33 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_34 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_35 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_36 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_37 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_38 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_39 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_40 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_41 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_42 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_43 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_44 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_45 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_46 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_47 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_48 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_49 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_50 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_51 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_52 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_53 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_54 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_55 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_56 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_57 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_58 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_59 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_60 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_61 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_62 $($t)* |
| }; |
| ($($p:ident)::*, (_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _) $($t:tt)*) => { |
| $($p)::*::_63 $($t)* |
| }; |
| } |
