> If a book is too abstract it won't teach anything useful.
Lots of developers are curious about functional programming. Even if you don't program in a functional programming language, many principles of functional programming, such as pure functions, can be applied in any language. Almost all languages in use today, including JavaScript, C#, Java, Python and Rust have varying degrees of FP features. Understanding what FP is all about is helpful in learning those features.
I'd argue that the market for learning what FP is all about, and how you can apply FP features in traditional languages, is bigger than the market for learning specific FP languages such as OCaml, Scala, F# and so on.
But in order to teach something actually useful you need to provide code samples in a specific language. Speaking in generalities like 'Functional programming emphasizes pure functions' doesn't really tell people how to practice it.
Sure, and as I said before, provide examples in multiple languages, because the demographic I am talking about is interested in FP, not one particular FP language.
Overloading the learner with examples from multiple languages is also a bad teaching method. It just adds to the confusion and complexity. They will be overwhelmed with the different techniques needed to bolt functional programming on to various degrees in C#, JavaScript, Rust, etc.
When teaching, it's much better to teach as little as possible at a time, so that learners can absorb concepts easily through their working memory and then build on their knowledge over time.
Lots of developers are curious about functional programming. Even if you don't program in a functional programming language, many principles of functional programming, such as pure functions, can be applied in any language. Almost all languages in use today, including JavaScript, C#, Java, Python and Rust have varying degrees of FP features. Understanding what FP is all about is helpful in learning those features.
I'd argue that the market for learning what FP is all about, and how you can apply FP features in traditional languages, is bigger than the market for learning specific FP languages such as OCaml, Scala, F# and so on.