This is a bit misleading. You suggest that local variables are looked up by name in a dictionary, which is not the case. They are looked up by indexing into a C array, with the index being a constant in the bytecode. That's quite a lot simpler. Here is the corresponding code (look above for the definition of the GETLOCAL macro): https://github.com/python/cpython/blob/fc1ce810f1da593648b4d...

So your code should be more like:

    locals[a_idx] = locals[foo_idx]->__getattribute__('bar')(locals[b_idx])

But this isn't a very good rendering of the thing because it doesn't show the many redundant reference count increment/decrement pairs every time you touch a variable.

(Also, interpreter dispatch uses computed GOTOs instead of the plain switch on C compilers that support it.)