Basic Syntax

Variables

Vibe has two ways to declare variables: let for mutable values and const for immutable values.

Let (Mutable)

let count = 0
let name: text = "Alice"
count = count + 1  // OK - can reassign

Const (Immutable)

const API_KEY = "sk-..."
const MAX_RETRIES: number = 3
// API_KEY = "new"  // Error - cannot reassign const

Private Variables

Mark variables as private to exclude them from AI context:

private let apiSecret = "sensitive-data"
let publicInfo = "This is visible to AI"

// When AI processes prompts, it won't see apiSecret
do "Summarize the available data"

Literals

Strings

Use double quotes, single quotes, or backticks:

let s1 = "double quoted"
let s2 = 'single quoted'
let s3 = `template with {variable} interpolation`

Backticks support multi-line strings:

let poem = `Roses are red,
Violets are blue,
Vibe is great,
And so are you.`

All string types support {variable} interpolation:

let name = "Alice"
let greeting = "Hello {name}!"  // "Hello Alice!"

Note

In AI prompts, {var} behaves differently—it’s kept as a reference rather than expanded. To expand values in prompts, use !{var}. See AI Prompts.

Use backslash to escape braces:

let literal = "Use \{braces\} literally"  // "Use {braces} literally"
let path = "C:\\Users\\name"              // "C:\Users\name"

Numbers

let integer = 42
let negative = -10
let decimal = 3.14

Booleans

let yes = true
let no = false

Null

let maybe: text = null  // Type annotation required
let data: json = null   // OK - type is explicit
// let empty = null     // Error: cannot infer type from null

Arrays

let empty: text[] = []
let numbers = [1, 2, 3]
let names = ["Alice", "Bob", "Carol"]

Use + to concatenate arrays:

let a = [1, 2]
let b = [3, 4]
let combined = a + b  // [1, 2, 3, 4]

Objects

let person = { name: "Alice", age: 30 }
let config = { timeout: 5000, retries: 3 }

Operators

Arithmetic

Operator	Description
+	Addition / string / array concatenation
-	Subtraction
*	Multiplication
/	Division
%	Modulo

let sum = 10 + 5      // 15
let greeting = "Hello, " + name  // String concatenation

Comparison

Operator	Description
==	Equal
!=	Not equal
<	Less than
>	Greater than
<=	Less than or equal
>=	Greater than or equal

Logical

Operator	Description
and	Logical AND
or	Logical OR
not	Logical NOT (unary)

if x > 0 and x < 100 {
  print("In range")
}

if not isValid {
  print("Invalid")
}

Member Access

Object Properties

let person = { name: "Alice", age: 30 }
let name = person.name  // "Alice"

Array Indexing

let items = ["a", "b", "c", "d", "e"]
let first = items[0]    // "a"
let third = items[2]    // "c"

// Negative indices count from the end
let last = items[-1]    // "e"
let secondLast = items[-2]  // "d"

Array Slicing

Python-style slicing with [start:end] syntax:

let items = [1, 2, 3, 4, 5]
let slice = items[1:3]    // [2, 3]
let fromStart = items[:2] // [1, 2]
let toEnd = items[3:]     // [4, 5]

// Negative indices in slices
let allButLast = items[:-1]   // [1, 2, 3, 4]
let lastTwo = items[-2:]      // [4, 5]
let middle = items[1:-1]      // [2, 3, 4]

Comments

// Single-line comment
let x = 42  // Inline comment

/* Multi-line
   block comment */