Variables in Bliss

Variables are declared using the let keyword.

Syntax

let <name>: <Type> = <expr>;

Or declared without an initial value:

let <name>: <Type>;

Scalar Types

Scalar variables hold a single value. Bliss provides the following scalar types:

Category	Types
Signed integers	i8, i16, i32, i64
Unsigned integers	u8, u16, u32, u64
Floating point	f32, f64
Boolean	bool — valid values are true and false

let age: u8 = 21;
let temperature: f32 = 36.6;
let active: bool = true;

Arrays

Arrays hold a sequence of values of the same type. In Bliss, arrays are fixed in size and cannot be resized once created.

There are two ways to declare an array:

let name: Type[] = [];        // initialized with values
let name: Type[size];         // pre-defined size, uninitialized

let scores: u8[] = [ 10, 20, 30 ];
let buffer: u8[256];

Array Assignment

Individual elements can be assigned using an index:

arr[index] = 10;

If the index is out of bounds, Bliss raises an unrecoverable error. Because array assignment is a statement and not an expression, it does not resolve into a Result — there is no way to handle or recover from the failure.

Rules

• A type annotation is always required.
• The initializer expression is optional — a variable can be declared without one, leaving it unassigned.
• When provided, the expression must evaluate to a value compatible with the declared type.
• Arrays are fixed — their size cannot change after creation.
• Out-of-bounds array assignment is an unrecoverable error.

Reassignment

A variable can be reassigned after declaration using =:

x = 10;
active = false;

Compound assignment operators are not valid in Bliss:

x += 1;  // ❌ invalid
x -= 1;  // ❌ invalid

Use a full reassignment instead:

x = x + 1;  // ✅
x = x - 1;  // ✅

Syntax Reference

Part	Required?	Description
name	✅	The variable's identifier
: Type	✅	The variable's type
= <expr>	❌	Initial value; any expression of the matching type
Type[]	✅	Array of Type, initialized with values
Type[size]	✅	Array of Type with a pre-defined fixed size
arr[index] = <expr>	—	Assigns a value to an array element; out-of-bounds is unrecoverable