$schemamarkup = get_post_meta(get_the_ID(), 'schemamarkup', true); if(!empty($schemamarkup)) { echo $schemamarkup; }

How to Get Started with LUA Programming on Gnu/Linux Distros

GNU/Linux Lua Programming QuickStart Guide

How to Getting Started with LUA 5.x Programming on GNU/Linux desktops – Step by step Tutorials.

Lua combines simple Procedural Syntax with powerful Data Description constructs based on Associative Arrays and Extensible Semantics.

Lua is Dynamically Typed, runs by interpreting Bytecode for a register-based Virtual Machine.

And has Automatic Memory Management with incremental Garbage Collection, making it ideal for Configuration, Scripting, and rapid Prototyping.

How to Get Started with LUA Programming on GNU/Linux Distros

GNU/Linux LUA Compiler Installation Guides