ringbuffer

stable

A fixed-capacity circular buffer that overwrites the oldest element when full, with FIFO push/pop and random access.

use plugin ringbuffer::{RingBuffer.new, push, pop, …}

13 functions Utilities

Runs with the native Zolo host

Plugin snippets can be edited in the Playground, but native capabilities are executed locally with the Zolo CLI.

/ filter jk navigate Esc clear

Functions (13)

RingBuffer.new Create a ring buffer with a fixed capacity
push Add a value, overwriting oldest if full
pop Remove and return the oldest value
peek Read the oldest value without removing it
peek_back Read the most recently pushed value
get Read a value by index without removing it
len Return the number of stored elements
capacity Return the maximum capacity
is_empty Check if the buffer is empty
is_full Check if the buffer is at capacity
contains Check if a value is present
clear Remove all elements
to_table Return all elements as an ordered table

From import to result

01Import only what you use
02Copy the smallest example
03Run it with the Zolo CLI

RingBuffer.new(capacity) → RingBuffer

Create a ring buffer with a fixed capacity

Creates a new ring buffer with the given fixed capacity. Once full, pushing a new value silently overwrites the oldest element.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(4)
buf.push(10)
buf.push(20)
buf.push(30)
buf.push(40)
buf.push(50)  // overwrites 10
print(buf.len())  // 4

push(self, value) → nil

Add a value, overwriting oldest if full

Appends a value to the back of the buffer. If the buffer is full, the oldest (front) element is discarded to make room.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(3)
buf.push("a")
buf.push("b")
buf.push("c")
buf.push("d")  // "a" is dropped
print(buf.peek())  // b

pop(self) → any

Remove and return the oldest value

Removes and returns the oldest element (FIFO order). Returns nil if the buffer is empty.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(3)
buf.push(1)
buf.push(2)
print(buf.pop())  // 1
print(buf.pop())  // 2
print(buf.pop())  // nil

peek(self) → any

Read the oldest value without removing it

Returns the oldest element without removing it. Returns nil if empty.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(3)
buf.push("first")
print(buf.peek())  // first
print(buf.len())   // 1 (unchanged)

peek_back(self) → any

Read the most recently pushed value

Returns the most recently pushed element without removing it. Returns nil if empty. Useful for inspecting the latest value in a sensor stream.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(5)
buf.push(100)
buf.push(200)
buf.push(300)
print(buf.peek_back())  // 300

get(self, index) → any

Read a value by index without removing it

Returns the element at the given zero-based index (oldest = 0). Returns nil if out of range. Does not remove the element.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(4)
buf.push("x")
buf.push("y")
buf.push("z")
print(buf.get(1))  // y

len(self) → int

Return the number of stored elements

Returns the number of elements currently in the buffer.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(10)
buf.push(1)
buf.push(2)
print(buf.len())  // 2

capacity(self) → int

Return the maximum capacity

Returns the fixed capacity the buffer was created with.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(8)
print(buf.capacity())  // 8

is_empty(self) → bool

Check if the buffer is empty

Returns true if the buffer contains no elements.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(3)
print(buf.is_empty())  // true
buf.push(1)
print(buf.is_empty())  // false

is_full(self) → bool

Check if the buffer is at capacity

Returns true if the number of elements equals the capacity.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(2)
buf.push("a")
buf.push("b")
print(buf.is_full())  // true

contains(self, value) → bool

Check if a value is present

Returns true if the buffer contains an element equal to value. Supports int, float, bool, string, and nil comparisons.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(5)
buf.push("apple")
buf.push("banana")
print(buf.contains("apple"))   // true
print(buf.contains("cherry"))  // false

clear(self) → nil

Remove all elements

Removes all elements, resetting the buffer to empty while keeping its capacity.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(4)
buf.push(1)
buf.push(2)
buf.clear()
print(buf.len())  // 0

to_table(self) → table

Return all elements as an ordered table

Returns all current elements as a 1-indexed table in FIFO order (oldest first). Does not modify the buffer.

use plugin ringbuffer::{RingBuffer}

let buf = RingBuffer.new(4)
buf.push("a")
buf.push("b")
buf.push("c")
let t = buf.to_table()
print(t[1])  // a
print(t[2])  // b

View source code