rasa

Type-safe ETS tables, queues, and counters for Gleam.

Install

Requires OTP 27 or later.

gleam add rasa@2

Usage

Tables

Key-value stores backed by ETS. Configure the table type (Set or OrderedSet) and access level (Public, Protected, or Private) using the builder pattern.

import rasa/table

pub fn main() -> Nil {
  let tabula = table.new()
  |> table.with_kind(table.Set)
  |> table.with_access(table.Private)
  |> table.build

  let assert Ok(Nil) = table.insert(tabula, "nature", 30)
  let assert Ok(Nil) = table.insert(tabula, "nurture", 70)

  // insert_new only inserts if the key doesn't already exist
  let assert Error(Nil) = table.insert_new(tabula, "nature", 0)
  let assert Ok(30) = table.lookup(tabula, "nature")
}

Queues

FIFO queues backed by ordered ETS tables. Each queue requires a counter to generate indices.

import rasa/counter
import rasa/queue
import rasa/table

pub fn main() -> Nil {
  let q = queue.new()
  |> queue.with_counter(counter.atomic())
  |> queue.with_access(table.Private)
  |> queue.build

  let assert Ok(1) = queue.push(q, "first")
  let assert Ok(2) = queue.push(q, "second")

  // Remove an item by index without popping
  let assert Ok(Nil) = queue.delete(q, 1)

  let assert Ok("second") = queue.pop(q)
}

Counters

Atomic counters for generating sequential or time-based indices.

import rasa/counter
import rasa/monotonic

pub fn main() -> Nil {
  // Atomic counter that increments by 1 each call
  let c = counter.atomic()
  assert 1 == counter.next(c)
  assert 2 == counter.next(c)

  // Monotonic time counter with nanosecond precision
  let m = counter.monotonic_time(monotonic.Nanosecond)
  let _t = counter.next(m)

  // Monotonic counter with guaranteed unique values
  let u = counter.monotonic()
  let _v = counter.next(u)

  // Custom counter from any function
  let always_99 = counter.new(fn() { 99 })
  assert 99 == counter.next(always_99)
}

Further documentation can be found at https://hexdocs.pm/rasa.

Development

gleam test  # Run the tests