#readwise # The Test Data Generator Applicative Functor  ## Metadata - Author: [[Mark Seemann]] - Full Title: The Test Data Generator Applicative Functor by Mark Seemann - URL: https://blog.ploeh.dk/2018/11/26/the-test-data-generator-applicative-functor/ ## Highlights - I tend to **think of applicative functors as an abstraction of 'combinations' of values and functions, but this is most evident for lists and other collections.** Even so, I think that the intuition also holds for [Maybe as an applicative functor](https://blog.ploeh.dk/2018/10/29/the-maybe-applicative-functor) as well as [validation as an applicative functor](https://blog.ploeh.dk/2018/11/05/applicative-validation). This is also the case for the [Test Data Generator functor](https://blog.ploeh.dk/2017/09/18/the-test-data-generator-functor). ([View Highlight](https://read.readwise.io/read/01gvzb0jkf3t13p26p8zmz86wh)) - Applicative functors are fairly common. I find it intuitive to think of them as an abstraction of how to make combinations of things. Modelling a Test Data Generator as an applicative functor enables you to create random combinations of functions and values. ([View Highlight](https://read.readwise.io/read/01gvzbmszkfd6mrjnf3kmjhga2))