Struct futures_util::stream::TryReadyChunks

impl<St: TryStream> TryReadyChunks<St>

pub fn get_ref(&self) -> &St

Acquires a reference to the underlying sink or stream that this combinator is pulling from.

pub fn get_mut(&mut self) -> &mut St

Acquires a mutable reference to the underlying sink or stream that this combinator is pulling from.

Note that care must be taken to avoid tampering with the state of the sink or stream which may otherwise confuse this combinator.

pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut St>

Acquires a pinned mutable reference to the underlying sink or stream that this combinator is pulling from.

Note that care must be taken to avoid tampering with the state of the sink or stream which may otherwise confuse this combinator.

pub fn into_inner(self) -> St

Consumes this combinator, returning the underlying sink or stream.

Note that this may discard intermediate state of this combinator, so care should be taken to avoid losing resources when this is called.

Trait Implementations§

impl<St: Debug + TryStream> Debug for TryReadyChunks<St>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

impl<St: TryStream + FusedStream> FusedStream for TryReadyChunks<St>

fn is_terminated(&self) -> bool

Returns true if the stream should no longer be polled.

impl<S, Item> Sink<Item> for TryReadyChunks<S>
where S: TryStream + Sink<Item>,

type Error = <S as Sink<Item>>::Error

The type of value produced by the sink when an error occurs.

fn poll_ready( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>

Attempts to prepare the Sink to receive a value. Read more

fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), Self::Error>

Begin the process of sending a value to the sink. Each call to this function must be preceded by a successful call to poll_ready which returned Poll::Ready(Ok(())). Read more

fn poll_flush( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>

Flush any remaining output from this sink. Read more

fn poll_close( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>

Flush any remaining output and close this sink, if necessary. Read more

impl<St: TryStream> Stream for TryReadyChunks<St>

type Item = Result<Vec<<St as TryStream>::Ok>, TryReadyChunksError<<St as TryStream>::Ok, <St as TryStream>::Error>>

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_> ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted. Read more

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream. Read more

impl<'pin, St: TryStream> Unpin for TryReadyChunks<St>
where Origin<'__pin, St>: Unpin,

Auto Trait Implementations§

impl<St> UnwindSafe for TryReadyChunks<St>
where St: UnwindSafe,

Blanket Implementations§

impl<T> Any for T
where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

impl<T> Borrow<T> for T
where T: ?Sized,

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

impl<T> BorrowMut<T> for T
where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

fn from(t: T) -> T

Returns the argument unchanged.

impl<T, U> Into for T
where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

impl<T, Item> SinkExt<Item> for T
where T: Sink<Item> + ?Sized,

fn with<U, Fut, F, E>(self, f: F) -> With<Self, Item, U, Fut, F>
where F: FnMut(U) -> Fut, Fut: Future<Output = Result<Item, E>>, E: From<Self::Error>, Self: Sized,

Composes a function in front of the sink. Read more

fn with_flat_map<U, St, F>(self, f: F) -> WithFlatMap<Self, Item, U, St, F>
where F: FnMut(U) -> St, St: Stream<Item = Result<Item, Self::Error>>, Self: Sized,

Composes a function in front of the sink. Read more

fn sink_map_err<E, F>(self, f: F) -> SinkMapErr<Self, F>
where F: FnOnce(Self::Error) -> E, Self: Sized,

Transforms the error returned by the sink.

fn sink_err_into<E>(self) -> SinkErrInto<Self, Item, E>
where Self: Sized, Self::Error: Into<E>,

Map this sink’s error to a different error type using the Into trait. Read more

fn buffer(self, capacity: usize) -> Buffer<Self, Item>
where Self: Sized,

Adds a fixed-size buffer to the current sink. Read more

fn close(&mut self) -> Close<'_, Self, Item> ⓘ
where Self: Unpin,

Close the sink.

fn fanout<Si>(self, other: Si) -> Fanout<Self, Si>
where Self: Sized, Item: Clone, Si: Sink<Item, Error = Self::Error>,

Fanout items to multiple sinks. Read more

fn flush(&mut self) -> Flush<'_, Self, Item> ⓘ
where Self: Unpin,

Flush the sink, processing all pending items. Read more

fn send(&mut self, item: Item) -> Send<'_, Self, Item> ⓘ
where Self: Unpin,

A future that completes after the given item has been fully processed into the sink, including flushing. Read more

fn feed(&mut self, item: Item) -> Feed<'_, Self, Item> ⓘ
where Self: Unpin,

A future that completes after the given item has been received by the sink. Read more

fn send_all<'a, St>(&'a mut self, stream: &'a mut St) -> SendAll<'a, Self, St> ⓘ
where St: TryStream<Ok = Item, Error = Self::Error> + Stream + Unpin + ?Sized, Self: Unpin,

A future that completes after the given stream has been fully processed into the sink, including flushing. Read more

fn left_sink<Si2>(self) -> Either<Self, Si2> ⓘ
where Si2: Sink<Item, Error = Self::Error>, Self: Sized,

Wrap this sink in an Either sink, making it the left-hand variant of that Either. Read more

fn right_sink<Si1>(self) -> Either<Si1, Self> ⓘ
where Si1: Sink<Item, Error = Self::Error>, Self: Sized,

Wrap this stream in an Either stream, making it the right-hand variant of that Either. Read more

fn poll_ready_unpin( &mut self, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>
where Self: Unpin,

A convenience method for calling Sink::poll_ready on Unpin sink types.

fn start_send_unpin(&mut self, item: Item) -> Result<(), Self::Error>
where Self: Unpin,

A convenience method for calling Sink::start_send on Unpin sink types.

fn poll_flush_unpin( &mut self, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>
where Self: Unpin,

A convenience method for calling Sink::poll_flush on Unpin sink types.

fn poll_close_unpin( &mut self, cx: &mut Context<'_> ) -> Poll<Result<(), Self::Error>>
where Self: Unpin,

A convenience method for calling Sink::poll_close on Unpin sink types.

impl<T> StreamExt for T
where T: Stream + ?Sized,

fn next(&mut self) -> Next<'_, Self> ⓘ
where Self: Unpin,

Creates a future that resolves to the next item in the stream. Read more

fn into_future(self) -> StreamFuture<Self> ⓘ
where Self: Sized + Unpin,

Converts this stream into a future of (next_item, tail_of_stream). If the stream terminates, then the next item is None. Read more

fn map<T, F>(self, f: F) -> Map<Self, F>
where F: FnMut(Self::Item) -> T, Self: Sized,

Maps this stream’s items to a different type, returning a new stream of the resulting type. Read more

fn enumerate(self) -> Enumerate<Self>
where Self: Sized,

Creates a stream which gives the current iteration count as well as the next value. Read more

fn filter<Fut, F>(self, f: F) -> Filter<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Filters the values produced by this stream according to the provided asynchronous predicate. Read more

fn filter_map<Fut, T, F>(self, f: F) -> FilterMap<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = Option<T>>, Self: Sized,

Filters the values produced by this stream while simultaneously mapping them to a different type according to the provided asynchronous closure. Read more

fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>
where F: FnMut(Self::Item) -> Fut, Fut: Future, Self: Sized,

Computes from this stream’s items new items of a different type using an asynchronous closure. Read more

fn collect<C: Default + Extend<Self::Item>>(self) -> Collect<Self, C> ⓘ
where Self: Sized,

Transforms a stream into a collection, returning a future representing the result of that computation. Read more

fn unzip<A, B, FromA, FromB>(self) -> Unzip<Self, FromA, FromB> ⓘ
where FromA: Default + Extend<A>, FromB: Default + Extend, Self: Sized + Stream<Item = (A, B)>,

Converts a stream of pairs into a future, which resolves to pair of containers. Read more

fn concat(self) -> Concat<Self> ⓘ
where Self: Sized, Self::Item: Extend<<<Self as Stream>::Item as IntoIterator>::Item> + IntoIterator + Default,

Concatenate all items of a stream into a single extendable destination, returning a future representing the end result. Read more

fn count(self) -> Count<Self> ⓘ
where Self: Sized,

Drives the stream to completion, counting the number of items. Read more

fn cycle(self) -> Cycle<Self>
where Self: Sized + Clone,

Repeats a stream endlessly. Read more

fn fold<T, Fut, F>(self, init: T, f: F) -> Fold<Self, Fut, T, F> ⓘ
where F: FnMut(T, Self::Item) -> Fut, Fut: Future<Output = T>, Self: Sized,

Execute an accumulating asynchronous computation over a stream, collecting all the values into one final result. Read more

fn any<Fut, F>(self, f: F) -> Any<Self, Fut, F> ⓘ
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Execute predicate over asynchronous stream, and return true if any element in stream satisfied a predicate. Read more

fn all<Fut, F>(self, f: F) -> All<Self, Fut, F> ⓘ
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Execute predicate over asynchronous stream, and return true if all element in stream satisfied a predicate. Read more

fn flatten(self) -> Flatten<Self>
where Self::Item: Stream, Self: Sized,

Flattens a stream of streams into just one continuous stream. Read more

fn flatten_unordered( self, limit: impl Into<Option<usize>> ) -> FlattenUnordered<Self>
where Self::Item: Stream + Unpin, Self: Sized,

Flattens a stream of streams into just one continuous stream. Polls inner streams produced by the base stream concurrently. Read more

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>
where F: FnMut(Self::Item) -> U, U: Stream, Self: Sized,

Maps a stream like StreamExt::map but flattens nested Streams. Read more

fn flat_map_unordered<U, F>( self, limit: impl Into<Option<usize>>, f: F ) -> FlatMapUnordered<Self, U, F>
where U: Stream + Unpin, F: FnMut(Self::Item) -> U, Self: Sized,

Maps a stream like StreamExt::map but flattens nested Streams and polls them concurrently, yielding items in any order, as they made available. Read more

fn scan<S, B, Fut, F>(self, initial_state: S, f: F) -> Scan<Self, S, Fut, F>
where F: FnMut(&mut S, Self::Item) -> Fut, Fut: Future<Output = Option>, Self: Sized,

Combinator similar to StreamExt::fold that holds internal state and produces a new stream. Read more

fn skip_while<Fut, F>(self, f: F) -> SkipWhile<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Skip elements on this stream while the provided asynchronous predicate resolves to true. Read more

fn take_while<Fut, F>(self, f: F) -> TakeWhile<Self, Fut, F>
where F: FnMut(&Self::Item) -> Fut, Fut: Future<Output = bool>, Self: Sized,

Take elements from this stream while the provided asynchronous predicate resolves to true. Read more

fn take_until<Fut>(self, fut: Fut) -> TakeUntil<Self, Fut>
where Fut: Future, Self: Sized,

Take elements from this stream until the provided future resolves. Read more

fn for_each<Fut, F>(self, f: F) -> ForEach<Self, Fut, F> ⓘ
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = ()>, Self: Sized,

Runs this stream to completion, executing the provided asynchronous closure for each element on the stream. Read more

fn for_each_concurrent<Fut, F>( self, limit: impl Into<Option<usize>>, f: F ) -> ForEachConcurrent<Self, Fut, F> ⓘ
where F: FnMut(Self::Item) -> Fut, Fut: Future<Output = ()>, Self: Sized,

Runs this stream to completion, executing the provided asynchronous closure for each element on the stream concurrently as elements become available. Read more

fn take(self, n: usize) -> Take<Self>
where Self: Sized,

Creates a new stream of at most n items of the underlying stream. Read more

fn skip(self, n: usize) -> Skip<Self>
where Self: Sized,

Creates a new stream which skips n items of the underlying stream. Read more

fn fuse(self) -> Fuse<Self>
where Self: Sized,

Fuse a stream such that poll_next will never again be called once it has finished. This method can be used to turn any Stream into a FusedStream. Read more

fn by_ref(&mut self) -> &mut Self

Borrows a stream, rather than consuming it. Read more

fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the stream. Read more

fn boxed<'a>(self) -> BoxStream<'a, Self::Item>
where Self: Sized + Send + 'a,

Wrap the stream in a Box, pinning it. Read more

fn boxed_local<'a>(self) -> LocalBoxStream<'a, Self::Item>
where Self: Sized + 'a,

Wrap the stream in a Box, pinning it. Read more

fn buffered(self, n: usize) -> Buffered<Self>
where Self::Item: Future, Self: Sized,

An adaptor for creating a buffered list of pending futures. Read more

fn buffer_unordered(self, n: usize) -> BufferUnordered<Self>
where Self::Item: Future, Self: Sized,

An adaptor for creating a buffered list of pending futures (unordered). Read more

fn zip<St>(self, other: St) -> Zip<Self, St>
where St: Stream, Self: Sized,

An adapter for zipping two streams together. Read more

fn chain<St>(self, other: St) -> Chain<Self, St>
where St: Stream<Item = Self::Item>, Self: Sized,

Adapter for chaining two streams. Read more

fn peekable(self) -> Peekable<Self>
where Self: Sized,

Creates a new stream which exposes a peek method. Read more

fn chunks(self, capacity: usize) -> Chunks<Self>
where Self: Sized,

An adaptor for chunking up items of the stream inside a vector. Read more

fn ready_chunks(self, capacity: usize) -> ReadyChunks<Self>
where Self: Sized,

An adaptor for chunking up ready items of the stream inside a vector. Read more

fn forward<S>(self, sink: S) -> Forward<Self, S> ⓘ
where S: Sink<Self::Ok, Error = Self::Error>, Self: TryStream + Sized,

A future that completes after the given stream has been fully processed into the sink and the sink has been flushed and closed. Read more

fn split<Item>(self) -> (SplitSink<Self, Item>, SplitStream<Self>)
where Self: Sink<Item> + Sized,

Splits this Stream + Sink object into separate Sink and Stream objects. Read more

fn inspect<F>(self, f: F) -> Inspect<Self, F>
where F: FnMut(&Self::Item), Self: Sized,

Do something with each item of this stream, afterwards passing it on. Read more

fn left_stream(self) -> Either<Self, B> ⓘ
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the left-hand variant of that Either. Read more

fn right_stream(self) -> Either<B, Self> ⓘ
where B: Stream<Item = Self::Item>, Self: Sized,

Wrap this stream in an Either stream, making it the right-hand variant of that Either. Read more

fn poll_next_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Option<Self::Item>>
where Self: Unpin,

A convenience method for calling Stream::poll_next on Unpin stream types.

fn select_next_some(&mut self) -> SelectNextSome<'_, Self> ⓘ
where Self: Unpin + FusedStream,

Returns a Future that resolves when the next item in this stream is ready. Read more

impl<T, U> TryFrom for T
where U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

impl<T, U> TryInto for T
where U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

impl<S, T, E> TryStream for S
where S: Stream<Item = Result<T, E>> + ?Sized,

type Ok = T

The type of successful values yielded by this future

type Error = E

The type of failures yielded by this future

fn try_poll_next( self: Pin<&mut S>, cx: &mut Context<'_> ) -> Poll<Option<Result<<S as TryStream>::Ok, <S as TryStream>::Error>>>

Poll this TryStream as if it were a Stream. Read more

impl<S> TryStreamExt for S
where S: TryStream + ?Sized,

fn err_into<E>(self) -> ErrInto<Self, E>
where Self: Sized, Self::Error: Into<E>,

Wraps the current stream in a new stream which converts the error type into the one provided. Read more

fn map_ok<T, F>(self, f: F) -> MapOk<Self, F>
where Self: Sized, F: FnMut(Self::Ok) -> T,

Wraps the current stream in a new stream which maps the success value using the provided closure. Read more

fn map_err<E, F>(self, f: F) -> MapErr<Self, F>
where Self: Sized, F: FnMut(Self::Error) -> E,

Wraps the current stream in a new stream which maps the error value using the provided closure. Read more

fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F>
where F: FnMut(Self::Ok) -> Fut, Fut: TryFuture<Error = Self::Error>, Self: Sized,

Chain on a computation for when a value is ready, passing the successful results to the provided closure f. Read more

fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F>
where F: FnMut(Self::Error) -> Fut, Fut: TryFuture<Ok = Self::Ok>, Self: Sized,

Chain on a computation for when an error happens, passing the erroneous result to the provided closure f. Read more

fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F>
where F: FnMut(&Self::Ok), Self: Sized,

Do something with the success value of this stream, afterwards passing it on. Read more

fn inspect_err<F>(self, f: F) -> InspectErr<Self, F>
where F: FnMut(&Self::Error), Self: Sized,

Do something with the error value of this stream, afterwards passing it on. Read more

fn into_stream(self) -> IntoStream<Self>
where Self: Sized,

Wraps a TryStream into a type that implements Stream Read more

fn try_next(&mut self) -> TryNext<'_, Self> ⓘ
where Self: Unpin,

Creates a future that attempts to resolve the next item in the stream. If an error is encountered before the next item, the error is returned instead. Read more

fn try_for_each<Fut, F>(self, f: F) -> TryForEach<Self, Fut, F> ⓘ
where F: FnMut(Self::Ok) -> Fut, Fut: TryFuture<Ok = (), Error = Self::Error>, Self: Sized,

Attempts to run this stream to completion, executing the provided asynchronous closure for each element on the stream. Read more

fn try_skip_while<Fut, F>(self, f: F) -> TrySkipWhile<Self, Fut, F>
where F: FnMut(&Self::Ok) -> Fut, Fut: TryFuture<Ok = bool, Error = Self::Error>, Self: Sized,

Skip elements on this stream while the provided asynchronous predicate resolves to true. Read more

fn try_take_while<Fut, F>(self, f: F) -> TryTakeWhile<Self, Fut, F>
where F: FnMut(&Self::Ok) -> Fut, Fut: TryFuture<Ok = bool, Error = Self::Error>, Self: Sized,

Take elements on this stream while the provided asynchronous predicate resolves to true. Read more

fn try_for_each_concurrent<Fut, F>( self, limit: impl Into<Option<usize>>, f: F ) -> TryForEachConcurrent<Self, Fut, F> ⓘ
where F: FnMut(Self::Ok) -> Fut, Fut: Future<Output = Result<(), Self::Error>>, Self: Sized,

Attempts to run this stream to completion, executing the provided asynchronous closure for each element on the stream concurrently as elements become available, exiting as soon as an error occurs. Read more

fn try_collect<C: Default + Extend<Self::Ok>>(self) -> TryCollect<Self, C> ⓘ
where Self: Sized,

Attempt to transform a stream into a collection, returning a future representing the result of that computation. Read more

fn try_chunks(self, capacity: usize) -> TryChunks<Self>
where Self: Sized,

An adaptor for chunking up successful items of the stream inside a vector. Read more

fn try_ready_chunks(self, capacity: usize) -> TryReadyChunks<Self>
where Self: Sized,

An adaptor for chunking up successful, ready items of the stream inside a vector. Read more

fn try_filter<Fut, F>(self, f: F) -> TryFilter<Self, Fut, F>
where Fut: Future<Output = bool>, F: FnMut(&Self::Ok) -> Fut, Self: Sized,

Attempt to filter the values produced by this stream according to the provided asynchronous closure. Read more

fn try_filter_map<Fut, F, T>(self, f: F) -> TryFilterMap<Self, Fut, F>
where Fut: TryFuture<Ok = Option<T>, Error = Self::Error>, F: FnMut(Self::Ok) -> Fut, Self: Sized,

Attempt to filter the values produced by this stream while simultaneously mapping them to a different type according to the provided asynchronous closure. Read more

fn try_flatten_unordered( self, limit: impl Into<Option<usize>> ) -> TryFlattenUnordered<Self>
where Self::Ok: TryStream + Unpin, <Self::Ok as TryStream>::Error: From<Self::Error>, Self: Sized,

Flattens a stream of streams into just one continuous stream. Produced streams will be polled concurrently and any errors will be passed through without looking at them. If the underlying base stream returns an error, it will be immediately propagated. Read more

fn try_flatten(self) -> TryFlatten<Self>
where Self::Ok: TryStream, <Self::Ok as TryStream>::Error: From<Self::Error>, Self: Sized,

Flattens a stream of streams into just one continuous stream. Read more

fn try_fold<T, Fut, F>(self, init: T, f: F) -> TryFold<Self, Fut, T, F> ⓘ
where F: FnMut(T, Self::Ok) -> Fut, Fut: TryFuture<Ok = T, Error = Self::Error>, Self: Sized,

Attempt to execute an accumulating asynchronous computation over a stream, collecting all the values into one final result. Read more

fn try_concat(self) -> TryConcat<Self> ⓘ
where Self: Sized, Self::Ok: Extend<<<Self as TryStream>::Ok as IntoIterator>::Item> + IntoIterator + Default,

Attempt to concatenate all items of a stream into a single extendable destination, returning a future representing the end result. Read more

fn try_buffer_unordered(self, n: usize) -> TryBufferUnordered<Self>
where Self::Ok: TryFuture<Error = Self::Error>, Self: Sized,

Attempt to execute several futures from a stream concurrently (unordered). Read more

fn try_buffered(self, n: usize) -> TryBuffered<Self>
where Self::Ok: TryFuture<Error = Self::Error>, Self: Sized,

Attempt to execute several futures from a stream concurrently. Read more

fn try_poll_next_unpin( &mut self, cx: &mut Context<'_> ) -> Poll<Option<Result<Self::Ok, Self::Error>>>
where Self: Unpin,

A convenience method for calling TryStream::try_poll_next on Unpin stream types.

fn into_async_read(self) -> IntoAsyncRead<Self>
where Self: Sized + TryStreamExt<Error = Error>, Self::Ok: AsRef<[u8]>,

Adapter that converts this stream into an AsyncBufRead. Read more

fn try_all<Fut, F>(self, f: F) -> TryAll<Self, Fut, F> ⓘ
where Self: Sized, F: FnMut(Self::Ok) -> Fut, Fut: Future<Output = bool>,

Attempt to execute a predicate over an asynchronous stream and evaluate if all items satisfy the predicate. Exits early if an Err is encountered or if an Ok item is found that does not satisfy the predicate. Read more