Variables

Variables in Draft are declared with the @ prefix and are immutable by default.

Declaration

@name = "Draft"
@version = 1
@is_ready = true

Type Inference

Draft infers types from the assigned value:

@count = 42           @// Int
@price = 19.99        @// Float
@label = "Sale"       @// String
@active = true        @// Boolean
@items = [1, 2, 3]    @// Array<Int>

Explicit Types

You can specify types explicitly:

@count: Int = 42
@price: Float = 19.99
@label: String = "Sale"
@active: Boolean = true
@items: Array<Int> = [1, 2, 3]

Mutability

Variables are immutable (read-only) by default. Use mut to make them mutable:

@x = 5
@x = 10          @// Error: cannot reassign immutable variable

mut @y = 5
@y = 10          @// OK: y is mutable

Destructuring

Extract values from arrays, maps, or records:

@// Array destructuring
[@first, @second, @_rest] = [1, 2, 3, 4, 5]

@// Map destructuring
{@name: @userName, @age: @userAge} = get_user()

@// Record destructuring
{@x, @y} = @point

Scope

Variables are scoped to their block:

action example()
    @outer = "outside"
    if true
        @inner = "inside"
        write(@outer)  @// OK: can access outer scope
    fin if.
    write(@inner)     @// Error: @inner is out of scope
fin action.

Shadowing

Inner scopes can shadow outer variables:

@x = 10
if true
    @x = 20        @// Shadows outer @x
    write(@x)       @// Prints 20
fin if.
write(@x)           @// Prints 10

Constants

Use const for compile-time constants:

const MAX_SIZE = 1000
const PI = 3.14159
const APP_NAME = "Draft"

Constants are covered in detail in the Constants chapter.

Variable Naming Conventions

Convention	Use Case	Example
snake_case	Local variables	@user_name
snake_case	Module-level variables	@config_path
CONSTANT_CASE	Constants	MAX_SIZE
_underscore	Unused variables	@_unused

Global Variables

Global variables are declared at the module level. Prefer module functions over globals:

@// Module-level variable
@counter = 0

action increment()
    @counter = @counter + 1
fin action.

Next Steps

Continue to Constants and Types for more detail.