Comment by zahlman

From the README, features include:

> native code parsing speedups for most common platforms

Which is to say, roughly analogous to "relying on NumPy". (A well-designed system avoids repeatedly calling from Python to C and prefers to let loops live within the C code; that applies at least as much to tree-like data as array-like data.)

> I wish Python was at least as fast as Node (which also can have its own share of performance cliffs) It's possible that nowadays Python has JITs that improve performance to Java levels while keeping compatibility with most existing code - I haven't used Python professionally in quite a few years.

No guarantees, but have you tried PyPy? It's existed since 2007 and definitely improved over time.

I would say that "performance cliffs" are just endemic to programming. Even in C you find people writing bad algorithms because better ones seem (at least superficially) much harder to write — especially if the good algorithm requires, say, a hash table. (C++ standard library containers definitely ameliorate this effect, but you pay in code complexity, especially where templates are needed.) And on the other hand you sometimes see big improvements from dropping to assembly (cf. ffmpeg).