Liquid
From Just Solve the File Format Problem
Liquid is a template language developed by the online store platform Shopify, using Ruby. It consists of HTML with embedded logic that can do such things as insert other templates and display or act on variables. It is used to create layout templates for pages that have content inserted into them, but can do more complex things such as iterating through the shopping cart contents to take actions based on the products there.
Liquid is an open-source project.