Why is smalltalk not a functional programming language?

Question

With the renewed interest in functional programming languages, I\'ve seen some similitudes between Smalltalk and FPL, namely closures ( BlockClosures in Smalltalk ) Yet, Sm

Answer 1

Thank you all for all the answers.

I'll add mine here which basically is my ( probably miss) understanding of yours.

I think the criteria to call something OO or FP is they way "stuff" is built using the language; not how easy or hard is to do it, I mean, the mental paradigm used.

For instance, as the links shown, it may be harder to type something in Scala than in OCaml, but that doesn't make it less FPL ( maybe incomplete or impure, but definitely functional ); because the aim of Scala is to use functions as primary building blocks, rather than objects.

On the other hand, making easy to write a function in a language doesn't make it functional, if the style or the aim is to use another artifacts. Smalltalk for instance, make it very easy to write an anonymous block or to provide a pluggable sorting comparator, but that doesn't make it ANY Functional at all, because the focus is to use objects and pass messages. Blockclosures are just a mechanism to encode these messages ( not functions ) even if they look like just like they were functions.

The confusion comes, because OO and FP are orthogonal ( as Rahul stated via twitter ) , so, what it looks like a encoded message in Smalltalk, looks pretty much like an anonymous function in Scala. But doing something similar doesn't converts a language of one paradigm into another.

To make it worst, Scala also uses the OO paradigm, to make it easier for mainstream ( Java, C++, C# ) programmers to give the jump, and if you see, it have had way more success than any of the others FPL's did. And of course this was thank to Java ( IMHO if Clojure has any success will be for exactly the same reason, the JVM )

In conclusion: A programming language may be classified by the paradigm it uses to build "things". There are languages that are pure like [Smalltalk : OO, Haskell: Functional, C: Procedural], or hybrids, like Scala or multi paradigm , like C++, Ruby, Python.

The fact you can write one style with the other language, doesn't make it that language of that style. Like simulating Objects with Lisp doesn't make it OO nor using functions with Java make it Functional.

To answer the question, to be considered functional, Smalltalk would need to use functions as building blocks, which it doesn't because it uses objects.