Sinkable

Abstract type for values that implement the (sink) protocol. Sinkable values can be converted into sinks explicitly and used for type testing.

Sinkable is not constructible directly.

assert (type [] Sinkable)

Methods

sink

Returns a sink over the value.

Returns

Sink

Forwarded methods

x.foo(...) on a Sinkable means x.sink().foo(...), so Sink's methods can be called on the value directly:

Method	Description
put value	Writes a value
premap func	Transforms each value before it is written
prefilter pred	Writes only values for which pred is truthy

premap/prefilter are named for their direction — they act on values headed into the sink. A value that is both Sinkable and Iterable, such as an Array, offers those alongside map/filter, which run the opposite way:

let acc = []
let out = acc.premap (do |x| x * 2)
out.put 3
assert_eq $acc [6]
assert_eq [...acc.map (do |x| x + 1)] [7]