Before I started the project, I was already vaguely familiar with the notion of an inverted index [1]. That small bit of knowledge meant that I knew where to start looking for more information and saved me a ton of time. Inverted indices form the bulk of many search engines, with the big unknown being how you implement it. I just had to find an adequate data structure for my application.

To figure that out, I remember searching for articles on how to implement inverted indices. Once I had a list of candidate strategies and data structures, I used Wikipedia supplemented by some textbooks like Skiena's [2] and occasionally some (somewhat outdated) information from NIST [3]. I found Wikipedia quite detailed for all of the data structures for this problem, so it was pretty easy to compare the tradeoffs between different design choices here. I originally wanted to implement the inverted index as a hash table but decided to use a trie because it makes wildcard search easier to implement.

After I developed most of the backend, I looked for books on "information retrieval" in general. I found a history book (Bourne and Hahn 2003) on the development of these kind of search systems [4]. I read some portions of this book, and that helped confirm many of the design choices that I made. I actually was just doing what people traditionally did when they first built these systems in the 1960s and 1970s, albeit with more modern tools and much more information on hand.

The harder part of this project for me was writing the interpreter. I actually found YouTube videos on how to write recursive descent parsers to be the most helpful there, particular this one [5]. Textbooks were too theoretical and not concrete enough, though Crafting Interpreters was sometimes helpful [6].

[1] https://en.wikipedia.org/wiki/Inverted_index

[2] https://doi.org/10.1007/978-3-030-54256-6

[3] https://xlinux.nist.gov/dads/

[4] https://doi.org/10.7551/mitpress/3543.001.0001

[5] https://www.youtube.com/watch?v=SToUyjAsaFk

[6] https://craftinginterpreters.com/