String Interpolation

Kōdo supports f-strings for embedding expressions inside string literals.

Basic Usage

Prefix a string literal with f and use {expression} to embed values:

let name: String = "World"
let msg: String = f"Hello, {name}!"
// msg == "Hello, World!"

Expressions in Interpolation

Any expression can be embedded, including function calls, arithmetic, and field access:

let x: Int = 3
let y: Int = 4
let desc: String = f"Point({x}, {y})"

let sum: String = f"Total: {x + y}"

Type Conversion

Non-string types are automatically converted using built-in to_string functions:

• Int → kodo_int_to_string
• Float64 → kodo_float_to_string
• Bool → kodo_bool_to_string

How It Works

F-strings are desugared during compilation into string concatenation:

f"Hello, {name}!"
// becomes:
"Hello, " + name + "!"

For non-string expressions, a to_string call is inserted automatically.

Restrictions

• F-strings cannot be used inside contract expressions (requires/ensures).
• Nested f-strings are not supported in v1.