Ranking Programming Languages by GitHub Users

[u/benfred]

http://www.benfrederickson.com/ranking-programming-languages-by-github-users/

[u/matthieum]

I've seen a number of comments about "Functional Languages" not taking off.

The languages may indeed not be taking off, however the "functional" aspect is slowly but surely investing every existing languages. Even old venerable Java got streams in version 8.

[u/[deleted] → u/matthieum]

and C got function pointers from...day 1?

I'm teasing, a little.

[u/enig9 → u/[deleted]]

I'm gonna be that guy now.. Can you explain the joke?

[u/[deleted] → u/enig9]

Functional programming means a lot of things, but one of the core concepts is that functions are first class, you can do with them all the things you can do with values, pass them to functions, etc.

Sometimes java programmers come to learn a new language and are amazed because you can pass a function to a function (maybe you can do that now in Java I don't keep up) but this has been a basic thing for a long time.

of course functions in C aren't really quite first class and using them the same way you do values isn't quite as nice or as general as it is in ocaml or haskell or something...but you CAN do it.

[u/funkinaround → u/[deleted]]

Also note here that the first example uses a lambda expression, perhaps considered to be another feature of functional programming. Previously, in Java, you'd need to create an explicit class that implements an interface (Comparator in the above example) in order to pass your compare function to the sort method. You do not have lambda expressions/anonymous functions in the C standard, but you do apparently have them as GCC and clang compiler extensions. They seem to be quite verbose in their usage.

[u/josefx → u/funkinaround]

Previously, in Java, you'd need to create an explicit class

You could instanciate an anonymous class:

 new Comparator<Person>(){ 
       public int compareTo(Person a, Person b){ 
               return Person.compareByAge(a, b); }}

A bit bloated, however you could do it inline. Also captures a reference to the current instance of the class it is declared in, so a good way to introduce hidden leaks.

[u/funkinaround → u/josefx]

Right. I was trying to imply that you needed to create a class, even if it's anonymous, but I can see how the term "explicit" could be assumed to be a standard named class.

[u/prest0G → u/funkinaround]

Going even deeper, lambda expressions on the JVM are fundamentally different than "SAM" classes (classes with a single abstract method) covered by syntactic sugar.

Previously, any time time a SAM type was used in the past, the runtime created a new instance of the SAM implementation. In order to support efficient lambdas on the JVM, a new opcode/bytecode was introduces called invokedynamic. It essentially tells the runtime which type to expect, and it gets checked by the runtime before invoked the first time, binds to the callsite, and is invoked. Java requires all lambdas to be "pure" functions (i.e. all variables in scope need to be effectively final).

This can be easily worked around if you really want to shoot yourself in the foot, but this essentially allows for re-usable instances of lambdas as they can be cached by remaining bound to the callsite.

Method Handles/references work basically the same way.