karl3＠writeme.com wrote:
karl3＠writeme.com wrote:
GPT-4 User Come up with an analog to "goto" in python that engages the raw interpreter and/or bytecode systems of python to function. i want to try!
here's a cool thing you can do. this function disassembles itself. it shows a call to the function to get the stack frame and pass it to the disassembler:
122 RETURN_VALUE oops: exec(disassemble_self.__code__.replace(co_code=a.__code__.co_code)) Segmentation fault
import sys, dis def a1(): ... b = 1 ... return b ... def a2(): ... b = 1 ... b += 1 ... return b ... def a3(): ... b = 1 ... magicfunc() ... return b ... list(a1.__code__.co_code) [151, 0, 100, 1, 125, 0, 124, 0, 83, 0] list(a2.__code__.co_code) [151, 0, 100, 1, 125, 0, 124, 0, 100, 1, 122, 13, 0, 0, 125, 0, 124, 0, 83, 0] list(a3.__code__.co_code) [151, 0, 100, 1, 125, 0, 116, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 166, 0, 0, 0, 171, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 124, 0, 83, 0]
ok ummmm so what am i trying to do what happens if i mutate the code object on the stack frame? is that possible? likely not. how do i figure out if i can? i'm assuming the segfault was from indexing a nonexistent local variable name rather than changing something in-place
sys._getframe().f_code = sys._getframe().f_code Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: attribute 'f_code' of 'frame' objects is not writable
the frame doesn't seem to be writeable. further options: - force writeability of these attributes by engaging python internals - nonreturning what about exceptions? could i add an exception handler in the caller's stack and catch it ...? (unlikely but i could maybe place a global exception handler) if i interrupt their execution how do i know what their variables were at the time? what would happen if i forked() with memory changes? i could do these by trial :s uhhhh so for example i could fork and suspend, and then inspect the frozen child. of course i might as well just inspect my own stack!