from sys import settrace, stderr
from dis import disassemble, get_instructions


def gtrace(g_frame, g_event, g_arg):
  code = g_frame.f_code
  name = code.co_name
  insts = list(get_instructions(code))
  print(f'gtrace: {g_event}: {name}', file=stderr)
  disassemble(code)

  if g_event != 'call': return None

  prev_off = -1

  def ltrace(frame, event, arg):
    nonlocal prev_off
    assert frame.f_code == code
    line = frame.f_lineno
    offset = frame.f_lasti
    index = offset // 2 # as of python3.6, all instructions are 2 bytes.
    inst = insts[index]
    print(f'ltrace: {event}: {name}:{line}: {prev_off} -> {offset}: {inst.opname} {inst.argrepr}')
    prev_off = offset
    return ltrace

  return ltrace


settrace(gtrace, 1)


def f():
  print("f")
  g()
  1//0 # test raise tracing.

def g():
  print("g")

try:
  f()
except ZeroDivisionError as e:
  print('top-level exception:', e)