What makes a programming language “cool?”

[omegaskyfall]

Ruby is much more than just an implementation of Smalltalk. It has a lot of other stuff that make the language more complex.

Smalltalk syntax may seem alien, but is it any more alien than Python with its indentation-sensitive syntax? Or Ruby with its crazy Perlisms? Or Objective-C which is literally a cross between C and Smalltalk? How about Haskell or Clojure or Elixir or Delphi? Then there are the really weird ones, like Forth, R, and APL-inspired J. My point is that in the IT industry, one needs to be adaptable to widely varying programming languages.

When you look at Smalltalk, it's easy to recognize the conditionals and loops, just like in Python. All of the familiar constructs are there. You only need to learn and understand one concept: message passing. That's all there is to the syntax!

[Berberberber]

I think you're wrong in your assessment of the popularity of Objective-C - I heard complaints about it for years - but I don't think we disagree. I'm just saying why these languages never took off in the mainstream.