This course follows the traditional approach to writing parsers. These traditional approaches were developed in times when memory was scarce and where back-tracking was impossible, simply because files were too large to be stored in RAM. Back-tracking parsers are much easier to write and in most cases performance can be brought to acceptable levels by applying caching. I have experimented with developing interpreting parsers that work with user-friendly grammar representations, and discovered that using caching can result in acceptable performance. I also discovered that a small interpreter often is faster than generated code, probably due to a better CPU cache performance. For two examples of these approaches see: https://github.com/FransFaase/IParse and https://github.com/FransFaase/RawParser (WIP).