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0 pointsfbonetti10y ago0 comments

Sure, Javascript has first class functions, which I guess meets the bare minimum requirements for being a functional language, but it also lacks some key features:

* Pure functions - JS functions are essentially subroutines. They might return a useful value or they might mutate a bunch of stuff and interact with the outside world. Who knows? JS functions aren't guarunteed to return the same value, or any value at all.

* Immutability - Anything and everything can be mutated in JS, including the contents of objects that are defined using the new ES6 `const` keyword

* Curried functions by default - Although it's possible to compose or partially apply JS functions, it's not nearly as nice as Haskell or Elm.

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klibertp10y ago

You're influenced by only one part of FP world. Let's take Lisp, or even better: Scheme.

   * pure functions - all you said is equally true for Scheme
   * immutability - set-cdr! and many SRFIs: vectors, boxes, records...
   * curried by default - nope, not in Scheme either

There are other flavours of FP languages other than ML descendants. They are not "less functional" at all.

chc10y ago

It's true, not every language goes all-in on functional programming — but just because some functional languages are less strongly functional than others, that doesn't mean it makes sense to call every language currently in use a functional language.

I mean, it seems pretty useless to define "functional programming language" in a way that includes both C and OCaml just because you can pass functions around in both of them.

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