---
title: Standard Functions
description: Utility functions available in the standard library
---

These functions are available in all Runbooks as part of the standard library.

## Operators

Basic mathematical and comparison operators:

```hcl
// Addition
output "sum" {
    value = 1 + 2  // or std::add(1, 2)
}

// Subtraction
output "diff" {
    value = 5 - 3  // or std::minus(5, 3)
}

// Multiplication
output "product" {
    value = 4 * 3  // or std::multiply(4, 3)
}

// Division
output "quotient" {
    value = 10 / 2  // or std::div(10, 2)
}

// Modulo
output "remainder" {
    value = 10 % 3  // or std::modulo(10, 3)
}
```

## Hash Functions

```hcl
// SHA256 hash
output "hash" {
    value = std::sha256("hello world")
}

// Keccak256 hash
output "keccak" {
    value = std::keccak256("hello world")
}
```

## Hex Functions

```hcl
// Encode string's raw bytes to hex (returns string with 0x prefix)
output "hex" {
    value = std::encode_hex("hello, world")
}
// > hex: 0x68656c6c6f2c20776f726c64

// Decode from hex (returns buffer)
output "decoded" {
    value = std::decode_hex("0x68656c6c6f2c20776f726c64")
}
// > decoded: 0x68656c6c6f2c20776f726c64
```

## Base58 Functions

```hcl
// Encode to base58 (accepts buffer or hex string)
output "base58" {
    value = std::encode_base58("0x68656c6c6f")
}
// > base58: Cn8eVZg

// Decode from base58 (returns buffer)
output "decoded" {
    value = std::decode_base58("Cn8eVZg")
}
// > decoded: 0x68656c6c6f
```

## Base64 Functions

```hcl
// Encode to base64 (accepts buffer or hex string)
output "encoded" {
    value = std::encode_base64("0x48656c6c6f20776f726c6421")
}
// > encoded: SGVsbG8gd29ybGQh

// Decode from base64 (returns buffer)
output "decoded" {
    value = std::decode_base64("SGVsbG8gd29ybGQh")
}
// > decoded: 0x48656c6c6f20776f726c6421
```

## JSON Functions

```hcl
// Query JSON with jq syntax
output "message" {
    value = std::jq("{ \"message\": \"Hello world!\" }", ".message")
}
```

## List Functions

```hcl
// Get element at index
output "entry" {
    value = std::index(['a', 'b', 'c'], 1)  // Returns 'b'
}
```

## Assertion Functions

```hcl
// Assert equality
output "check_eq" {
    value = std::assert_eq(action.example.result, 1)
}

// Assert not equal
output "check_ne" {
    value = std::assert_ne(action.example.result, 0)
}

// Assert greater than / greater than or equal
output "check_gt" {
    value = std::assert_gt(action.example.result, 0)
}

// Assert less than / less than or equal
output "check_lt" {
    value = std::assert_lt(action.example.result, 100)
}
```