> For the complete documentation index, see [llms.txt](https://swlaschin.gitbook.io/fsharpforfunandprofit/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swlaschin.gitbook.io/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds.md).

# The "Recursive types and folds" Series

In this series, we'll look at recursive types and how to use them, and on the way, we'll look at catamorphisms, tail recursion, the difference between left and right folds, and more.

* [Introduction to recursive types](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds.md). Don't fear the catamorphism....
* [Catamorphism examples](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds-1b.md). Applying the rules to other domains.
* [Introducing Folds](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds-2.md). Threading state through a recursive data structure.
* [Understanding Folds](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds-2b.md). Recursion vs. iteration.
* [Generic recursive types](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds-3.md). Implementing a domain in three ways.
* [Trees in the real world](/fsharpforfunandprofit/functional-patterns/recursive-types-and-folds/recursive-types-and-folds-3b.md). Examples using databases, JSON and error handling.


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