Visualize.Feed.Signals (Visualize v0.4.0)

A signal (Visualize.Signals) as a feed: generated, pulled (spec/08 §11.6, D-140).

The feed's present tick is fixed (tick:, moved with at/2) or read from a clock (every: milliseconds per tick). Its schema describes the first field, the tick, as its window field — :number, since a tick is a count and not an instant, with window: true and labelled "Tick" (spec/08 §10.1, D-154) — and every other field :number, under whatever describe: adds. It honours :window: a window is ticks, served up to the present tick, at most limit: rows and capped beyond. A budget is left to visualize, and it does not push.

Examples

iex> signal = Visualize.Signals.new(:discrete, [:t, :n], window: 3)
iex> feed = Visualize.Feed.Signals.new(signal, tick: 10, describe: %{n: %{label: "Count"}})
iex> {_version, schema, [:window]} = Visualize.Feed.describe(feed)
iex> Visualize.Data.Schema.fetch(schema, :n, :label)
{:ok, "Count"}
iex> {:ok, delivery} = Visualize.Feed.fetch(feed, [4, 99], nil)
iex> {Enum.map(delivery.rows, & &1.t), delivery.window}
{[4, 5, 6, 7, 8, 9, 10], [4, 10]}

Summary

Types

t()

Functions

at(feed, tick)

A ticked feed moved to a tick.

new(signal, opts \\ [])

A signal as a feed. Options: describe: (descriptions merged over the defaults, field by field), tick: (the present tick, 0), every: (milliseconds per tick, read from clock: — a function of no argument in milliseconds, the monotonic clock by default — counted from origin:, the clock now), and limit: (the most rows one fetch serves, 10_000). Raises ArgumentError for a description the schema refuses.

Types

t()

@type t() :: %Visualize.Feed.Signals{
  clock: (-> integer()) | nil,
  every: pos_integer() | nil,
  limit: pos_integer(),
  origin: integer(),
  schema: Visualize.Data.Schema.t(),
  signal: Visualize.Signals.t(),
  tick: non_neg_integer()
}

Functions

at(feed, tick)

@spec at(t(), non_neg_integer()) :: t()

A ticked feed moved to a tick.

new(signal, opts \\ [])

@spec new(Visualize.Signals.t(), keyword()) :: t()