Libraries in VG Language

VG Language comes with a rich set of built-in libraries that provide additional functionality for your programs.

Importing Libraries

To use a library in your VG program, use the import statement:

import LibraryName.namespace;

You can import specific namespaces or functions from a library:

import MathLib.arithmetic;  ## Import the arithmetic namespace
import Guilibrary.window.create;  ## Import a specific function

Standard Libraries

MathLib

Mathematical functions and constants.

Namespace: arithmetic

Functions for basic arithmetic operations.

Function	Description	Parameters	Return Value	Example
add(a, b)	Adds two numbers	a: First number b: Second number	Sum of a and b	arithmetic.add(5, 10) → 15
subtract(a, b)	Subtracts second number from first	a: First number b: Second number	Difference of a and b	arithmetic.subtract(20, 5) → 15
multiply(a, b)	Multiplies two numbers	a: First number b: Second number	Product of a and b	arithmetic.multiply(4, 3) → 12
divide(a, b)	Divides first number by second	a: First number b: Second number	Quotient of a and b	arithmetic.divide(10, 2) → 5
abs(x)	Gets absolute value	x: Number	Absolute value of x	arithmetic.abs(-15) → 15

Namespace: constants

Mathematical constants.

Constant	Description	Return Value	Example
pi()	Returns the value of π	Approximately 3.14159	constants.pi() → 3.14159...
e()	Returns the value of e	Approximately 2.71828	constants.e() → 2.71828...

Usage Example

import MathLib.arithmetic;
import MathLib.constants;

var pi = constants.pi();
var sum = arithmetic.add(5, 10);
var difference = arithmetic.subtract(20, 5);
var product = arithmetic.multiply(4, 3);
var quotient = arithmetic.divide(10, 2);
var absoluteValue = arithmetic.abs(-15);

Guilibrary

GUI components for creating graphical applications.

Namespace: window

Functions for creating and managing windows.

Function	Description	Parameters	Return Value	Example
create(title, width, height)	Creates a new window	title: Window title width: Window width height: Window height	Window object	window.create("My App", 800, 600)
setBackgroundColor(window, color)	Sets window background color	window: Window object color: Color (hex code)	None	window.setBackgroundColor(gameWindow, "#87CEEB")
addComponentToWindow(window, component)	Adds a component to window	window: Window object component: UI component	None	window.addComponentToWindow(gameWindow, image)
launch(window)	Displays the window	window: Window object	None	window.launch(gameWindow)

Namespace: Image

Functions for creating and manipulating images.

Function	Description	Parameters	Return Value	Example
createImage(path, x, y, width, height)	Creates an image component	path: Image file path x: X position y: Y position width: Width height: Height	Image object	Image.createImage("logo.png", 100, 100, 200, 200)

Namespace: IOEvents

Functions for handling user input events.

Function	Description	Parameters	Return Value	Example
setOnKeyPress(window, callback)	Sets key press event handler	window: Window object callback: Function to call when key is pressed	None	See example below

Namespace: Sound

Functions for playing audio.

Function	Description	Parameters	Return Value	Example
playSound(path)	Plays a sound file	path: Sound file path	None	Sound.playSound("click.wav")

Usage Example

import Guilibrary.window;
import Guilibrary.Image;
import Guilibrary.IOEvents;
import Guilibrary.Sound;

## Create a window
var gameWindow = window.create("My Application", 800, 600);
window.setBackgroundColor(gameWindow, "#87CEEB");

## Add components
var image = Image.createImage("assets/logo.png", 100, 100, 200, 200);
window.addComponentToWindow(gameWindow, image);

## Set up event handling
IOEvents.setOnKeyPress(gameWindow, function(key) {
    if (key == "SPACE") {
        Sound.playSound("assets/click.wav");
    }
});

## Display the window
window.launch(gameWindow);

RegexLib

Regular expression operations.

Namespace: regex

Functions for pattern matching and text manipulation.

Function	Description	Parameters	Return Value	Example
findAll(text, pattern)	Finds all matches of a pattern	text: Input text pattern: Regex pattern	Array of matches	regex.findAll("Hello world", "\\w+")
matches(text, pattern)	Checks if text matches pattern	text: Input text pattern: Regex pattern	Boolean	regex.matches("test@example.com", "^[\\w.]+@[\\w.]+\\.[a-z]{2,}$")
replaceAll(text, pattern, replacement)	Replaces all matches	text: Input text pattern: Regex pattern replacement: Replacement text	Modified text	regex.replaceAll("Hello world", "world", "universe")

Usage Example

import RegexLib.regex;

## Find all matches
var matches = regex.findAll("Hello world", "\\w+");

## Check if a string matches a pattern
var isMatch = regex.matches("test@example.com", "^[\\w.]+@[\\w.]+\\.[a-z]{2,}$");

## Replace text
var newText = regex.replaceAll("Hello world", "world", "universe");

SQLiteLib

Database operations with SQLite.

Namespace: db

Functions for database operations.

Function	Description	Parameters	Return Value	Example
openDB(path)	Opens or creates a database	path: Database file path	Database connection	db.openDB("mydata.db")
runStatement(db, sql)	Executes SQL statement	db: Database connection sql: SQL statement	None	db.runStatement(database, "CREATE TABLE users (id INTEGER, name TEXT)")
runQuery(db, sql)	Executes SQL query	db: Database connection sql: SQL query	Query results	db.runQuery(database, "SELECT * FROM users")
closeDB(db)	Closes database connection	db: Database connection	None	db.closeDB(database)

Usage Example

import SQLiteLib.db;

## Open or create a database
var database = db.openDB("mydata.db");

## Create a table
db.runStatement(database, "CREATE TABLE IF NOT EXISTS users (id INTEGER, name TEXT)");

## Insert data
db.runStatement(database, "INSERT INTO users VALUES (1, 'John')");

## Query data
var results = db.runQuery(database, "SELECT * FROM users");
print(results);

## Close the database
db.closeDB(database);

DateTime

Date and time functions.

Namespace: timestamp

Functions for working with timestamps.

Function	Description	Parameters	Return Value	Example
currentTimeMillis()	Gets current time in milliseconds	None	Current timestamp	timestamp.currentTimeMillis()

Namespace: date

Functions for working with dates.

Function	Description	Parameters	Return Value	Example
getYear()	Gets current year	None	Current year	date.getYear()
getMonth()	Gets current month	None	Current month (1-12)	date.getMonth()
getDay()	Gets current day	None	Current day of month	date.getDay()

Namespace: time

Functions for working with time.

Function	Description	Parameters	Return Value	Example
getHour()	Gets current hour	None	Current hour (0-23)	time.getHour()
getMinute()	Gets current minute	None	Current minute (0-59)	time.getMinute()
getSecond()	Gets current second	None	Current second (0-59)	time.getSecond()

Usage Example

import DateTime.timestamp;
import DateTime.date;
import DateTime.time;

## Get current timestamp
var now = timestamp.currentTimeMillis();

## Get date components
var year = date.getYear();
var month = date.getMonth();
var day = date.getDay();

## Get time components
var hour = time.getHour();
var minute = time.getMinute();
var second = time.getSecond();

IO

File and console input/output operations.

Namespace: File

Functions for file operations.

Function	Description	Parameters	Return Value	Example
readFile(path)	Reads file contents	path: File path	File contents as string	File.readFile("input.txt")
writeFile(path, content)	Writes to a file	path: File path content: Content to write	None	File.writeFile("output.txt", "Hello, world!")
appendToFile(path, content)	Appends to a file	path: File path content: Content to append	None	File.appendToFile("log.txt", "Program executed")

Namespace: Prompt

Functions for user input.

Function	Description	Parameters	Return Value	Example
input(prompt)	Gets user input	prompt: Text to display	User input as string	Prompt.input("Enter your name: ")

Usage Example

import IO.File;
import IO.Prompt;

## Read user input
var name = Prompt.input("Enter your name: ");
print("Hello, " + name);

## File operations
File.writeFile("output.txt", "Hello, world!");
var content = File.readFile("input.txt");
File.appendToFile("log.txt", "Program executed at " + DateTime.timestamp.currentTimeMillis());

OSLib

Operating system information and environment variables.

Namespace: sys

Functions for system information.

Function	Description	Parameters	Return Value	Example
getOSName()	Gets operating system name	None	OS name as string	sys.getOSName()
getUserHome()	Gets user home directory	None	Path as string	sys.getUserHome()
getUserDir()	Gets current directory	None	Path as string	sys.getUserDir()
getEnv(name)	Gets environment variable	name: Variable name	Variable value	sys.getEnv("PATH")

Usage Example

import OSLib.sys;

## Get OS information
var osName = sys.getOSName();
print("Running on: " + osName);

## Get environment variables
var homePath = sys.getUserHome();
var currentDir = sys.getUserDir();
var envVar = sys.getEnv("PATH");

Arrays

Array manipulation utilities.

Namespace: array

Functions for working with arrays.

Function	Description	Parameters	Return Value	Example
getLength(arr)	Gets array length	arr: Array	Length as integer	array.getLength(myArray)
push(arr, item)	Adds item to end of array	arr: Array item: Item to add	Modified array	array.push(myArray, 4)
pop(arr)	Removes last item from array	arr: Array	Removed item	array.pop(myArray)
unshift(arr, item)	Adds item to start of array	arr: Array item: Item to add	Modified array	array.unshift(myArray, 0)
shift(arr)	Removes first item from array	arr: Array	Removed item	array.shift(myArray)

Usage Example

import Arrays.array;

## Create an array
var myArray = [1, 2, 3];

## Get array length
var length = array.getLength(myArray);

## Modify arrays
array.push(myArray, 4);  ## Add to end: [1, 2, 3, 4]
var lastItem = array.pop(myArray);  ## Remove from end: [1, 2, 3]
array.unshift(myArray, 0);  ## Add to beginning: [0, 1, 2, 3]
var firstItem = array.shift(myArray);  ## Remove from beginning: [1, 2, 3]

Util

Utility functions for type conversion and string operations.

Namespace: Type

Functions for type checking.

Function	Description	Parameters	Return Value	Example
getType(value)	Gets type of a value	value: Any value	Type as string	Type.getType("Hello") → "string"

Namespace: String

Functions for string operations.

Function	Description	Parameters	Return Value	Example
toString(value)	Converts value to string	value: Any value	String representation	String.toString(123) → "123"
stringLength(str)	Gets string length	str: String	Length as integer	String.stringLength("Hello") → 5
indexOf(str, substr)	Finds position of substring	str: String substr: Substring to find	Position as integer	String.indexOf("Hello World", "World") → 6
substring(str, start, end)	Extracts part of string	str: String start: Start index end: End index	Substring	String.substring("Hello World", 0, 5) → "Hello"
toUpper(str)	Converts string to uppercase	str: String	Uppercase string	String.toUpper("hello") → "HELLO"

Namespace: Integer

Functions for integer operations.

Function	Description	Parameters	Return Value	Example
toInt(str)	Converts string to integer	str: String	Integer value	Integer.toInt("42") → 42

Namespace: Double

Functions for double operations.

Function	Description	Parameters	Return Value	Example
toDouble(str)	Converts string to double	str: String	Double value	Double.toDouble("3.14") → 3.14

Namespace: Boolean

Functions for boolean operations.

Function	Description	Parameters	Return Value	Example
toBoolean(str)	Converts string to boolean	str: String	Boolean value	Boolean.toBoolean("true") → true

Usage Example

import Util.Type;
import Util.String;
import Util.Integer;
import Util.Double;
import Util.Boolean;

## Type checking
var type = Type.getType("Hello");  ## Returns "string"

## Type conversion
var intValue = Integer.toInt("42");
var doubleValue = Double.toDouble("3.14");
var boolValue = Boolean.toBoolean("true");
var strValue = String.toString(123);

## String operations
var length = String.stringLength("Hello");
var position = String.indexOf("Hello World", "World");
var part = String.substring("Hello World", 0, 5);
var upper = String.toUpper("hello");

Random

Random number generation.

Namespace: number

Functions for generating random numbers.

Function	Description	Parameters	Return Value	Example
getRandomInt(min, max)	Generates random integer	min: Minimum value max: Maximum value	Random integer	number.getRandomInt(1, 100)
getRandomDouble(min, max)	Generates random double	min: Minimum value max: Maximum value	Random double	number.getRandomDouble(0, 1)

Usage Example

import Random.number;

## Generate random numbers
var randomInt = number.getRandomInt(1, 100);  ## Random integer between 1 and 100
var randomDouble = number.getRandomDouble(0, 1);  ## Random double between 0 and 1

Creating Custom Libraries

You can create your own libraries using the library keyword:

library MyLibrary {
    namespace utils {
        function greet(name) {
            return "Hello, " + name + "!";
        }

        function farewell(name) {
            return "Goodbye, " + name + "!";
        }
    }

    namespace math {
        function square(x) {
            return x * x;
        }
    }
}

Save this code in a file with the .vglib extension in the libraries or projects/packages directory to make it available for import in your VG programs.

Library Documentation

When creating libraries, it's good practice to document your functions using documentation comments:

library MyLibrary {
    /## Utility functions for common operations
    # This namespace contains helper functions for everyday tasks.
    # @author Your Name
    ##/
    namespace utils {
        /## Greets a person by name
        # @param name The name of the person to greet
        # @return A greeting message
        ##/
        function greet(name) {
            return "Hello, " + name + "!";
        }
    }
}

System Calls in Libraries

Libraries often use system calls to access Java functionality. These calls are restricted to a whitelist of allowed classes and methods defined in the configuration file.

## Example of a system call in a library function
function currentTimeMillis() {
    return VgSystemCall("java.lang.System", "currentTimeMillis");
}

Library Namespaces

Libraries can contain multiple namespaces to organize related functionality:

library MyLibrary {
    namespace math {
        ## Math-related functions
    }

    namespace string {
        ## String manipulation functions
    }

    namespace file {
        ## File handling functions
    }
}

To use functions from different namespaces, import each namespace separately:

import MyLibrary.math;
import MyLibrary.string;

var squared = math.square(5);
var reversed = string.reverse("Hello");