Comment by int_19h
1 year ago
Python is arguably easier since you don't need to handle non-native stacks at all; you just have a straightforward mapping of Python operations to C functions that you call with regular arguments, as usual.
1 year ago
Python is arguably easier since you don't need to handle non-native stacks at all; you just have a straightforward mapping of Python operations to C functions that you call with regular arguments, as usual.
With Python's extension API, you have to carefully incref and decref Python values to ensure that you don't either leak memory or deallocate data that's still in use. That's what the Lua stack interface saves you. It's not a call stack, which seems to be what you're thinking of.
Lifetimes and references are things to consider in Lua integration code too. See luaL_ref() rationale and why you can’t lua_pop() a string that is in use. The fact that gc doesn’t happen instantly 99.99999% of the times doesn’t save you from thinking about it.
Not that this was a hard topic in a language where lifetimes are the main concern and business as usual. In C/etc you can’t hold anything without a ref or some sort of a lifetime guarantee. What makes it special wrt Lua/Python?
Yeah, I didn't mean to say you didn't have to think about lifetimes at all when embedding Lua, just that the stack, weird as it is, seems to simplify that kind of thing rather than complicating it (even if you do occasionally have to luaL_ref). But if there's a clearly better alternative, I'd like to know about it. Constantly calling Py_INCREF and Py_DECREF isn't it.
Delayed GC seems like it might add headaches for this kind of thing rather than removing them, because your bugs may take a while to show up in testing.
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Indeed, but the rules for doing so are straightforward and easy to apply almost mechanically. Indeed, if you are writing in C++ or Rust, you just use a smart pointer that does it for you.