ToPull<O>

classToPull<O>

Provides high-level inspection methods for a Rills's underlying Pull.

Constructors

ToPull()

ToPull(Rill<O>self)

Implementation

dart

ToPull(this.self);

Properties

echo no setter

Pull<O,Unit>getecho

Runs the underlying pull, effectively "echoing" the rill.

Implementation

dart

Pull<O, Unit> get echo => self.underlying;

hashCode no setter inherited

intgethashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Inherited from Object.

Implementation

dart

external int get hashCode;

last no setter

Pull<Never,Option<O>>getlast

Returns the last element emitted, or none if the rill is empty.

Implementation

dart

Pull<Never, Option<O>> get last {
  Pull<Never, Option<O>> go(Option<O> prev, Rill<O> s) {
    return s.pull.uncons.flatMap((hdtl) {
      return hdtl.foldN(
        () => Pull.pure(prev),
        (hd, tl) => go(hd.lastOption, tl),
      );
    });
  }

  return go(none(), self);
}

peek no setter

Pull<Never,Option<Record>>getpeek

Peeks at the next chunk without consuming it; the chunk is prepended back to the remainder so subsequent pulls see the same data.

Implementation

dart

Pull<Never, Option<(Chunk<O>, Rill<O>)>> get peek => uncons.flatMap(
  (hdtl) => hdtl.foldN(
    () => Pull.pure(const None()),
    (hd, tl) => Pull.pure(Some((hd, tl.cons(hd)))),
  ),
);

peek1 no setter

Pull<Never,Option<Record>>getpeek1

Like peek but exposes the first single element instead of the whole chunk.

Implementation

dart

Pull<Never, Option<(O, Rill<O>)>> get peek1 => uncons.flatMap(
  (hdtl) => hdtl.foldN(
    () => Pull.pure(const None()),
    (hd, tl) => Pull.pure(Some((hd.head, tl.cons(hd)))),
  ),
);

runtimeType no setter inherited

TypegetruntimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

dart

external Type get runtimeType;

self final

finalRill<O>self

Implementation

dart

final Rill<O> self;

uncons no setter

Pull<Never,Option<Record>>getuncons

Peels off the next chunk, wrapping the remainder back into a Rill.

Implementation

dart

Pull<Never, Option<(Chunk<O>, Rill<O>)>> get uncons {
  return self.underlying.uncons.map((opt) {
    return opt.mapN((chunk, rest) {
      return (chunk, rest.rillNoScope);
    });
  });
}

uncons1 no setter

Pull<Never,Option<Record>>getuncons1

Peels off exactly one element, wrapping the remainder into a Rill.

Implementation

dart

Pull<Never, Option<(O, Rill<O>)>> get uncons1 {
  return uncons.flatMap((hdtl) {
    return hdtl.foldN(
      () => Pull.pure(const None()),
      (hd, tl) {
        final ntl = hd.size == 1 ? tl : tl.cons(hd.drop(1));
        return Pull.pure(Some((hd[0], ntl)));
      },
    );
  });
}

Methods

drop()

Pull<O,Option<Rill<O>>>drop(intn)

Skips the first n elements and returns the remainder of the rill.

Implementation

dart

Pull<O, Option<Rill<O>>> drop(int n) {
  if (n <= 0) {
    return Pull.pure(Some(self));
  } else {
    return uncons.flatMap((opt) {
      return opt.foldN(
        () => Pull.pure(none()),
        (hd, tl) {
          final m = hd.size;

          if (m < n) {
            return tl.pull.drop(n - m);
          } else if (m == n) {
            return Pull.pure(Some(tl));
          } else {
            return Pull.pure(Some(tl.cons(hd.drop(n))));
          }
        },
      );
    });
  }
}

dropThrough()

Pull<Never,Option<Rill<O>>>dropThrough(boolFunction(O)p)

Like dropWhile but also drops the first element for which p is false.

Implementation

dart

Pull<Never, Option<Rill<O>>> dropThrough(Function1<O, bool> p) => _dropWhile(p, true);

dropWhile()

Pull<Never,Option<Rill<O>>>dropWhile(boolFunction(O)p)

Drops elements while p is true and returns the remainder of the rill.

Implementation

dart

Pull<Never, Option<Rill<O>>> dropWhile(Function1<O, bool> p) => _dropWhile(p, false);

fold()

Pull<Never,O2>fold<O2>(O2z,O2Function(O2,O)f)

Folds the entire rill into a single value, returning it as the Pull result.

Implementation

dart

Pull<Never, O2> fold<O2>(O2 z, Function2<O2, O, O2> f) => uncons.flatMap((hdtl) {
  return hdtl.foldN(
    () => Pull.pure(z),
    (hd, tl) {
      final acc = hd.foldLeft(z, f);
      return tl.pull.fold(acc, f);
    },
  );
});

fold1()

Pull<Never,Option<O>>fold1(OFunction(O,O)f)

Folds using f with no initial accumulator, returning none for empty streams.

Implementation

dart

Pull<Never, Option<O>> fold1(Function2<O, O, O> f) => uncons.flatMap((hdtl) {
  return hdtl.foldN(
    () => Pull.pure(none()),
    (hd, tl) {
      final fst = hd.drop(1).foldLeft(hd[0], f);
      return tl.pull.fold(fst, f).map((o) => Some(o));
    },
  );
});

forall()

Pull<Never,bool>forall(boolFunction(O)p)

Checks a predicate for all elements, short-circuiting on failure.

Implementation

dart

Pull<Never, bool> forall(Function1<O, bool> p) {
  return uncons.flatMap((opt) {
    return opt.foldN(
      () => Pull.pure(true),
      (hd, tl) => hd.forall(p) ? tl.pull.forall(p) : Pull.pure(false),
    );
  });
}

noSuchMethod() inherited

dynamicnoSuchMethod(Invocationinvocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dart

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

dart

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

dart

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

scanChunks()

Pull<O2,S>scanChunks<S, O2>(Sinitial,RecordFunction(S,Chunk<O>)f,);

Runs a stateful transformation chunk-by-chunk, emitting transformed chunks.

Implementation

dart

Pull<O2, S> scanChunks<S, O2>(S initial, Function2<S, Chunk<O>, (S, Chunk<O2>)> f) =>
    scanChunksOpt(initial, (s) => Some((c) => f(s, c)));

scanChunksOpt()

Pull<O2,S>scanChunksOpt<S, O2>(Sinitial,Option<RecordFunction(Chunk<O>)>Function(S)f,);

Like scanChunks but allows early termination by returning none from f.

Implementation

dart

Pull<O2, S> scanChunksOpt<S, O2>(
  S initial,
  Function1<S, Option<Function1<Chunk<O>, (S, Chunk<O2>)>>> f,
) {
  Pull<O2, S> go(S acc, Rill<O> s) {
    return f(acc).fold(
      () => Pull.pure(acc),
      (g) {
        return s.pull.uncons.flatMap((hdtl) {
          return hdtl.foldN(
            () => Pull.pure(acc),
            (hd, tl) {
              final (s2, c) = g(hd);
              return Pull.output(c).append(() => go(s2, tl));
            },
          );
        });
      },
    );
  }

  return go(initial, self);
}

take()

Pull<O,Option<Rill<O>>>take(intn)

Emits the first n elements and returns the remainder of the Rill.

Implementation

dart

Pull<O, Option<Rill<O>>> take(int n) {
  if (n <= 0) {
    return Pull.pure(const None());
  } else {
    return uncons.flatMap((opt) {
      return opt.foldN(
        () => Pull.pure(none()),
        (hd, tl) {
          final m = hd.size;

          if (m < n) {
            return Pull.output(hd).flatMap((_) => tl.pull.take(n - m));
          } else if (m == n) {
            return Pull.output(hd).as(Some(tl));
          } else {
            final (pfx, sfx) = hd.splitAt(n);
            return Pull.output(pfx).as(Some(tl.cons(sfx)));
          }
        },
      );
    });
  }
}

takeRight()

Pull<Never,Chunk<O>>takeRight(intn)

Emits the last n elements as a single chunk, consuming the full rill.

Implementation

dart

Pull<Never, Chunk<O>> takeRight(int n) {
  Pull<Never, Chunk<O>> go(Chunk<O> acc, Rill<O> s) {
    return s.pull.unconsN(n, allowFewer: true).flatMap((hdtl) {
      return hdtl.foldN(
        () => Pull.pure(acc),
        (hd, tl) => go(acc.drop(hd.size).concat(hd), tl),
      );
    });
  }

  if (n <= 0) {
    return Pull.pure(Chunk.empty());
  } else {
    return go(Chunk.empty(), self);
  }
}

takeThrough()

Pull<O,Option<Rill<O>>>takeThrough(boolFunction(O)p)

Like takeWhile but also emits the first element for which p is false.

Implementation

dart

Pull<O, Option<Rill<O>>> takeThrough(Function1<O, bool> p) => _takeWhile(p, true);

takeWhile()

Pull<O,Option<Rill<O>>>takeWhile(boolFunction(O)p, {booltakeFailure=false,});

Emits elements while p is true and returns the remainder of the rill.

When takeFailure is true, the first failing element is emitted before stopping (equivalent to takeThrough).

Implementation

dart

Pull<O, Option<Rill<O>>> takeWhile(Function1<O, bool> p, {bool takeFailure = false}) =>
    _takeWhile(p, takeFailure);

toString() inherited

StringtoString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Object.

Implementation

dart

external String toString();

unconsLimit()

Pull<Never,Option<Record>>unconsLimit(intn)

Peels off a chunk of at most n elements, wrapping the remainder.

Implementation

dart

Pull<Never, Option<(Chunk<O>, Rill<O>)>> unconsLimit(int n) {
  if (n <= 0) {
    return Pull.pure(Some((Chunk.empty(), self)));
  } else {
    return uncons.flatMap((hdtl) {
      return hdtl.foldN(
        () => Pull.pure(none()),
        (hd, tl) {
          if (hd.size < n) {
            return Pull.pure(Some((hd, tl)));
          } else {
            final (out, rem) = hd.splitAt(n);
            return Pull.pure(Some((out, tl.cons(rem))));
          }
        },
      );
    });
  }
}

unconsMin()

Pull<Never,Option<Record>>unconsMin(intn, {boolallowFewerTotal=false,});

Accumulates at least n elements into a single chunk before returning.

Returns none if the stream ends with fewer than n elements and allowFewerTotal is false; otherwise returns whatever was accumulated.

Implementation

dart

Pull<Never, Option<(Chunk<O>, Rill<O>)>> unconsMin(
  int n, {
  bool allowFewerTotal = false,
}) {
  Pull<Never, Option<(Chunk<O>, Rill<O>)>> go(Chunk<O> acc, int n, Rill<O> s) {
    return s.pull.uncons.flatMap((hdtl) {
      return hdtl.foldN(
        () {
          if (allowFewerTotal && acc.nonEmpty) {
            return Pull.pure(Some((acc, Rill.empty())));
          } else {
            return Pull.pure(none());
          }
        },
        (hd, tl) {
          if (hd.size < n) {
            return go(acc.concat(hd), n - hd.size, tl);
          } else {
            return Pull.pure(Some((acc.concat(hd), tl)));
          }
        },
      );
    });
  }

  if (n <= 0) {
    return Pull.pure(Some((Chunk.empty(), self)));
  } else {
    return go(Chunk.empty(), n, self);
  }
}

unconsN()

Pull<Never,Option<Record>>unconsN(intn, {boolallowFewer=false})

Peels off exactly n elements in a single chunk.

If the stream ends before n elements are available and allowFewer is true, returns what was accumulated; otherwise returns none.

Implementation

dart

Pull<Never, Option<(Chunk<O>, Rill<O>)>> unconsN(
  int n, {
  bool allowFewer = false,
}) {
  if (n <= 0) {
    return Pull.pure(Some((Chunk.empty(), self)));
  } else {
    return unconsMin(n, allowFewerTotal: allowFewer).map((hdtl) {
      return hdtl.mapN((hd, tl) {
        final (pfx, sfx) = hd.splitAt(n);
        return (pfx, tl.cons(sfx));
      });
    });
  }
}

Operators

operator ==() inherited

booloperator ==(Objectother)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

Total: It must return a boolean for all arguments. It should never throw.
Reflexive: For all objects o, o == o must be true.
Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.
Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Object.

Implementation

dart

external bool operator ==(Object other);

ToPull<O> ​

Constructors ​

ToPull() ​

Properties ​

echo no setter ​

hashCode no setter inherited ​

last no setter ​

peek no setter ​

peek1 no setter ​

runtimeType no setter inherited ​

self final ​

uncons no setter ​

uncons1 no setter ​

Methods ​

drop() ​

dropThrough() ​

dropWhile() ​

fold() ​

fold1() ​

forall() ​

noSuchMethod() inherited ​

scanChunks() ​

scanChunksOpt() ​

take() ​

takeRight() ​

takeThrough() ​

takeWhile() ​

toString() inherited ​

unconsLimit() ​

unconsMin() ​

unconsN() ​

Operators ​

operator ==() inherited ​

ToPull<O>

Constructors

ToPull()

Properties

echo no setter

hashCode no setter inherited

last no setter

peek no setter

peek1 no setter

runtimeType no setter inherited

self final

uncons no setter

uncons1 no setter

Methods

drop()

dropThrough()

dropWhile()

fold()

fold1()

forall()

noSuchMethod() inherited

scanChunks()

scanChunksOpt()

take()

takeRight()

takeThrough()

takeWhile()

toString() inherited

unconsLimit()

unconsMin()

unconsN()

Operators

operator ==() inherited