Basic Signal

A signal is a reactive state cell. Create one by passing the initial value to signal(). From there, .get() reads the current value and .set(v) replaces it. Signals accept any type: integers, strings, maps, arrays, structs.

Creating, reading and writing signals with distinct values.

01-signal-basics.zolo

Playground

// Feature: signals — fine-grained reactive state

// Syntax: `signal(initial)` creates a cell; `s.get()` reads,

// `s.set(v)` writes. Reads inside `effect` / `computed`

// register a dependency.

// When to use: UI state, derived values, cache invalidation —

// anywhere "X depends on Y" should re-run when Y changes.


use std::Signal

let s = signal(42)
print(s.get())
// expected: 42


s.set(100)
print(s.get())
// expected: 100


// Signals carry any value: ints, strings, maps, arrays, structs.

let name = signal("zolo")
name.set("lang")
print(name.get())
// expected: lang

Challenge

Create a list signal, add elements with .modify(|v| { ... }) and print the size after each modification.