"Good performance": Within a factor of ~2 to ~4 of native C. No one said idiomatic Lisp was performant. They said Lisp was performant. Seriously, it's not e

"Good performance": Within a factor of ~2 to ~4 of native C. No one said idiomatic Lisp was performant. They said Lisp was performant. Seriously, it's not even difficult. It's not like it's a situation where it's easy to accidentally kill your performance by writing elegant code while having no idea why it's slow. Optimizing a Lisp codebase is a straightforward exercise, no more difficult than optimizing a Lua or Javascript codebase. If someone hasn't shipped more than a toy program with Lisp, it's easy to believe the opposite. But if you try it, you'll see that it's true.