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Walrus provides a standard library through an import system that gives you access to file I/O, system operations, and math utilities. Modules are imported using the import statement and return a dictionary of functions.

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Import system

Modules are imported using string literals that specify the module path: 
import "std/io";
import "std/sys";
import "std/math";

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Import with alias

You can alias imported modules for shorter or more descriptive names: 
import "std/sys" as system;
import "std/io" as files;

let home = system.env_get("HOME");
files.write_file("output.txt", "Hello!");

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Available modules

The Walrus standard library includes three main modules:

std/io

File I/O operations including reading, writing, and handle-based streaming

std/sys

System operations like environment variables, command-line arguments, and process control

std/math

Mathematical functions, constants, and random number generation

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Module structure

Each module exports functions as properties of a dictionary. After importing, you access functions using dot notation: 
import "std/io";

// The import returns a dictionary with function properties
let content = io.read_file("config.txt");
io.write_file("output.txt", content);

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Error handling

Standard library functions return error values or throw runtime errors when operations fail: 
import "std/io";
import "std/sys";

// Functions that may fail return void on error
let value = sys.env_get("MISSING_VAR");
if value == void {
    println("Environment variable not found");
}

// File operations throw errors if they fail
let handle = io.file_open("data.txt", "r");  // Error if file doesn't exist

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Built-in functions

In addition to the standard library modules, Walrus provides built-in functions that are always available without importing: 
// No import needed for built-ins
let count = len([1, 2, 3]);  // 3
let name = str(42);           // "42"
let kind = type(true);        // "bool"
See the Built-in functions page for the complete reference.

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