Lola is designed to be a simple hardware description language for describing synchronous, digital circuits.
Niklaus Wirth developed the language to teach digital design on field-programmable gate arrays (FPGAs) to computer science students while a professor at ETH Zurich.
It describes digital electronics hardware on the logic gate level in the form of signal assignments.
The MODULE Adder defined in this example can serve as a building block on a higher level of the design hierarchy.
An overview of the whole system of tools for digital design is the technical report Tools for Digital Circuit Design using FPGAs (containing a copy of the report on the language Lola Lola: An Object-Oriented Logic Description Language).