final class Pull[+F[_], +O, +R] extends AnyVal
A p: Pull[F,O,R] reads values from one or more streams, returns a
result of type R, and produces a Stream[F,O] when calling p.stream.
Any resources acquired by p are freed following the call to stream.
Laws:
Pull forms a monad in R with pure and flatMap:
pure >=> f == ff >=> pure == f(f >=> g) >=> h == f >=> (g >=> h)wheref >=> gis defined asa => a flatMap f flatMap g
raiseError is caught by handleErrorWith:
handleErrorWith(raiseError(e))(f) == f(e)
- Source
- Pull.scala
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final
def
!=(arg0: Any): Boolean
- Definition Classes
- Any
-
final
def
##(): Int
- Definition Classes
- Any
- def +(other: String): String
- def ->[B](y: B): (Pull[F, O, R], B)
-
final
def
==(arg0: Any): Boolean
- Definition Classes
- Any
-
def
>>[F2[x] >: F[x], O2 >: O, R2](p2: ⇒ Pull[F2, O2, R2]): Pull[F2, O2, R2]
Alias for
flatMap(_ => p2). -
def
as[R2](r2: R2): Pull[F, O, R2]
Alias for
_.map(_ => o2). -
final
def
asInstanceOf[T0]: T0
- Definition Classes
- Any
-
def
attempt: Pull[F, O, Either[Throwable, R]]
Returns a pull with the result wrapped in
Right, or an error wrapped inLeftif the pull has failed. -
def
covary[F2[x] >: F[x]]: Pull[F2, O, R]
Lifts this pull to the specified effect type.
-
def
covaryAll[F2[x] >: F[x], O2 >: O, R2 >: R]: Pull[F2, O2, R2]
Lifts this pull to the specified effect type, output type, and resource type.
-
def
covaryOutput[O2 >: O]: Pull[F, O2, R]
Lifts this pull to the specified output type.
-
def
covaryResource[R2 >: R]: Pull[F, O, R2]
Lifts this pull to the specified resource type.
- def ensuring(cond: (Pull[F, O, R]) ⇒ Boolean, msg: ⇒ Any): Pull[F, O, R]
- def ensuring(cond: (Pull[F, O, R]) ⇒ Boolean): Pull[F, O, R]
- def ensuring(cond: Boolean, msg: ⇒ Any): Pull[F, O, R]
- def ensuring(cond: Boolean): Pull[F, O, R]
-
def
flatMap[F2[x] >: F[x], O2 >: O, R2](f: (R) ⇒ Pull[F2, O2, R2]): Pull[F2, O2, R2]
Applies the resource of this pull to
fand returns the result. - def formatted(fmtstr: String): String
-
def
getClass(): Class[_ <: AnyVal]
- Definition Classes
- AnyVal → Any
-
def
handleErrorWith[F2[x] >: F[x], O2 >: O, R2 >: R](h: (Throwable) ⇒ Pull[F2, O2, R2]): Pull[F2, O2, R2]
If
thisterminates withPull.raiseError(e), invokeh(e). -
final
def
isInstanceOf[T0]: Boolean
- Definition Classes
- Any
-
def
map[R2](f: (R) ⇒ R2): Pull[F, O, R2]
Applies the resource of this pull to
fand returns the result in a newPull. -
def
mapOutput[O2](f: (O) ⇒ O2): Pull[F, O2, R]
Applies the outputs of this pull to
fand returns the result in a newPull. -
def
onComplete[F2[x] >: F[x], O2 >: O, R2 >: R](p2: ⇒ Pull[F2, O2, R2]): Pull[F2, O2, R2]
Run
p2afterthis, regardless of errors duringthis, then reraise any errors encountered duringthis. -
def
scope: Pull[F, O, Unit]
Tracks any resources acquired during this pull and releases them when the pull completes.
-
def
stream: Stream[F, O]
Interpret this
Pullto produce aStream.Interpret this
Pullto produce aStream. The result typeRis discarded. -
def
streamNoScope: Stream[F, O]
Like stream but no scope is inserted around the pull, resulting in any resources being promoted to the current scope of the stream, extending the resource lifetime.
Like stream but no scope is inserted around the pull, resulting in any resources being promoted to the current scope of the stream, extending the resource lifetime. Typically used as a performance optimization, where resource lifetime can be extended in exchange for faster execution.
Caution: this can result in resources with greatly extended lifecycles if the pull discards parts of the stream from which it was created. This could lead to memory leaks so be very careful when using this function. For example, a pull that emits the first element and discards the tail could discard the release of one or more resources that were acquired in order to produce the first element. Normally, these resources would be registered in the scope generated by the pull-to-stream conversion and hence released as part of that scope closing but when using
streamNoScope, they get promoted to the current stream scope, which may be infinite in the worst case. -
def
toString(): String
- Definition Classes
- Any
- def →[B](y: B): (Pull[F, O, R], B)