PHP - Lua::__construct() Function

---

---

The PHP Lua::__construct() function is used to create a Lua constructor. You can use this function to bridge PHP and Lua for even more flexibility. Only the argument list for this function is available at this time; no documentation is available.

Syntax

Below is the syntax of the PHP Lua::__construct() function −

public Lua::__construct( string $lua_script_file = NULL )

Parameters

This function accepts $lua_script_file parameter which is the path to a Lua script file. This file, if provided, is automatically loaded into the Lua environment when the constructor is called.

Return Value

The __construct() function does not return anything. It simply creates and initializes a Lua environment.

PHP Version

The __construct() function is available from version 0.9.0 of the PECL lua extension onwards.

Example 1

Here is the basic example of the PHP Lua::__construct() function to load no scripts and builds a Lua environment. It offers a framework for dynamically executing PHP Lua code.

<?php
   // Create a new Lua environment
   $lua = new Lua();

   // Output to show the Lua environment is created
   echo "Lua environment initialized.\n";
?>

Output

Here is the outcome of the following code −

Lua environment initialized.

Example 2

In the below PHP code we will use the __construct() function for loading and executing a Lua script file at the time of initialization.

<?php
   // Lua script file path
   $scriptFile = '/PHP/PhpProjects/add_numbers.lua'; 

   // Pass the Lua script file to the constructor
   $lua = new Lua($scriptFile);

   // Lua script executes during initialization
   echo "Lua script loaded and executed during construction.\n";
?> 

Output

This will generate the below output −

Lua script loaded and executed during construction.

Example 3

This program shows dynamically passing inline Lua code to the constructor by saving it to a temporary file.

<?php
   // Create a temporary Lua script file 
   $tempFile = '/PHP/PhpProjects/temp_script.lua';
   file_put_contents($tempFile, "print('Hello from Lua!')");

   // Initialize Lua and load the temporary script file
   $lua = new Lua($tempFile);

   // Temporary script executes during initialization
   echo "Inline Lua script executed during construction.\n";

   // Cleanup the temporary file
   unlink($tempFile);
?> 

Output

This will create the below output −

Hello from Lua!
Inline Lua script executed during construction.