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by chrisseaton 1359 days ago
> so you'd call the pre-JIT JVM an "interpreter"

Yeah? I think almost everyone would?

> and you'd call Java an interpreted language?

Java is interpreted in many ways, and compiled in many ways, as I said it's complicated. It's compiled to bytecode, which is interpreted until it's time to be compiled... at which point it's abstract interpreted to a graph, which is compiled to machine code, until it needs to deoptimise at which point the metadata from the graph is interpreted again, allowing it to jump back into the original interpreter.

But if it didn't have the JIT it'd always be an interpreter running.

1 comments

I am not too concerned about the word "interpreter", and more about cPython being called an "interpreted language", which implies it works like Perl 5, or that cPython being an "interpreter" is somehow a problem. It's normal mode of operation works more like pre-JVM Java, with "interpreted bytecode" from .pyc files.
Most people don’t make this distinction, and would just say ‘interpreter’. Interpreting bytecode vs an AST is a pretty minor difference. It’s exactly the same data in a slightly different format. The ‘compilation’ is just a post-order linearisation. And storing it in files or not even more so.
as I'm sure you're aware, bytecode interpretation typically implies a superior performing model than AST interpretation, and compiling into bytecode produces a lot of opportunities for optimization that are not typically feasible when working with an AST directly. Of course it's all bits and anything is possible, but it's assumed to be a better approach in a generally non-subtle way.