All kudos to LATEX3!
LATEX is a high-quality typesetting system; it includes features designed for the production of technical and scientific documentation. LATEX is the de facto standard for the communication and publication of scientific documents. LATEX is available as free software.
The LATEX3 project is a long-term research project to develop the next version of the LATEX typesetting system. It aims at transforming LATEX to be much more compatible with the increasingly XML’ized document universe and to introduce modern programming paradigms to LATEX.
LATEX3 project introduced, among other things, array structure, regular expressions, floating point, key-value system with revolutionary innovations, improved token/string management, highly imaginative coffin concept wherein boxes can be manipulated at user’s will with remarkable ease, nested booleans, controlled macro expansion functionality, and above all newer concepts of defining functions resembling to that of mainstream languages.
Neptune and TEXFolio largely depend on LATEX3 methodologies and paradigms for its LATEX libraries and is the main reason behind the faster, efficient and accurate text processing of these frameworks. While adopting a modern web based interface for document processing, LATEX3 libraries and methods have greatly assisted to reach the goals seamlessly.