interpreter - Is Ruby really an interpreted language if all of its implementations are compiled into bytecode?

Question

In the chosen answer for this question about Blue Ruby, Chuck says:

All of the current Ruby implementations are compiled to bytecode. Contrary to SAP's claims, as of Ruby 1.9, MRI itself includes a bytecode compiler, though the ability to save the compiled bytecode to disk disappeared somewhere in the process of merging the YARV virtual machine. JRuby is compiled into Java .class files. I don't have a lot of details on MagLev, but it seems safe to say it will take that road as well.

I'm confused about this compilation/interpretation issue with respect to Ruby.

I learned that Ruby is an interpreted language and that's why when I save changes to my Ruby files I don't need to re-build the project.

But if all of the Ruby implementations now are compiled, is it still fair to say that Ruby is an interpreted language? Or am I misunderstanding something?

Answer 1

Nearly every language is "compiled" nowadays, if you count bytecode as being compiled. Even Emacs Lisp is compiled. Ruby was a special case because until recently, it wasn't compiled into bytecode.

I think you're right to question the utility of characterizing languages as "compiled" vs. "interpreted." One useful distinction, though, is whether the language creates machine code (e.g. x86 assembler) directly from user code. C, C++, many Lisps, and Java with JIT enabled do, but Ruby, Python, and Perl do not.

People who don't know better will call any language that has a separate manual compilation step "compiled" and ones that don't "interpreted."