Standard Library Reference

Kettle provides a comprehensive set of built-in functions for common programming tasks, quantum computing, and system interactions.

Quick Navigation

Category	Description
Types & Conversions	Type conversions, string operations, and math functions
Lists	List manipulation, higher-order functions, and aggregations
Quantum Operations	Qubit creation, gates, measurement, and entanglement
I/O & Environment	File operations and environment access

Function Categories

Types & Conversions

Core functions for working with basic types:

• Output: print - Display values
• Conversions: to_string, to_float, to_int, parse_float
• Strings: split, join, trim, substring, replace, and more
• Math: abs, sqrt, sin, cos, pow, floor, ceil

Lists

Functional list operations:

• Access: head, tail, last, get_at
• Transform: map, filter, fold, reverse
• Combine: append, concat, take, drop
• Aggregate: sum, mean, counts, most_common

Quantum Operations

All quantum functions require the Quantum effect:

• Creation: qubit, qubits, bell
• Single-Qubit Gates: hadamard, pauli_x, pauli_y, pauli_z, rx, ry, rz
• Multi-Qubit Gates: cnot, cz, swap, ccnot
• Measurement: measure, measure_all

I/O & Environment

System interaction functions:

• Files: read_file, write_file, file_exists
• Environment: get_env

Type Notation

Throughout this reference, we use the following type notation:

Notation	Meaning
T	Generic type parameter
List[T]	List containing elements of type T
Option[T]	Optional value (Some or None)
Result[T, E]	Result type (Ok or Err)
Tuple[A, B]	Tuple of two values
fn(A) -> B	Function from A to B

Effects

Some functions require specific effects to be declared:

-- Quantum operations require `with Quantum`
fn quantum_example() -> Int with Quantum
  q = qubit()
  q <- hadamard
  measure(q)
end fn

-- IO operations require `using` a handler
fn main() -> Unit using quantum_simulator, file_io
  print(quantum_example())
end fn

See Quantum Operations for details on the Quantum effect.