【8.4】python是如何实现生成器的

#!/user/bin/env python
# -*- coding:utf-8 -*-
import dis
import inspect
frame = None


def foo():
    bar()


def bar():
    global frame
    frame = inspect.currentframe()


# python.exe会用一个叫做PyEval_EvalFramEx(c函数)去执行foo函数，首先会创建一个栈帧（stack frame）
"""
python中一切皆对象，栈帧是一个对象（栈帧对象），字节码对象
当foo调用子函数bar，又会创建一个栈帧
所有的栈帧都是分配在堆内存上（堆内存不释放就一直存在），这就决定了栈帧可以独立于调用者存在
"""

print(dis.dis(foo))
foo()
# 打印出bar的栈帧
print(frame.f_code.co_name)
# 打印出foo的栈帧
caller_frame = frame.f_back
print(caller_frame)


def gen_func():
    yield 1
    name = 'zy'
    yield 2
    age = 21
    return 'ok'


gen = gen_func()
print(dis.dis(gen))

print(gen.gi_frame.f_lasti)
print(gen.gi_frame.f_locals)
next(gen)
print(gen.gi_frame.f_lasti)
print(gen.gi_frame.f_locals)
next(gen)
print(gen.gi_frame.f_lasti)
print(gen.gi_frame.f_locals)

# 我们可以控制函数的执行和暂停

  9           0 LOAD_GLOBAL              0 (bar)
              2 CALL_FUNCTION            0
              4 POP_TOP
              6 LOAD_CONST               0 (None)
              8 RETURN_VALUE
None
bar
<frame at 0x000002BBCE39DE58, file 'demo.py', line 9, code foo>
<generator object gen_func at 0x000002BBD0218930>

C:UsersAdministratorPythonimooc>python demo.py
  9           0 LOAD_GLOBAL              0 (bar)
              2 CALL_FUNCTION            0
              4 POP_TOP
              6 LOAD_CONST               0 (None)
              8 RETURN_VALUE
None
bar
<frame at 0x0000025478CADE58, file 'demo.py', line 9, code foo>
 34           0 LOAD_CONST               1 (1)
              2 YIELD_VALUE
              4 POP_TOP

 35           6 LOAD_CONST               2 ('zy')
              8 STORE_FAST               0 (name)

 36          10 LOAD_CONST               3 (2)
             12 YIELD_VALUE
             14 POP_TOP

 37          16 LOAD_CONST               4 (21)
             18 STORE_FAST               1 (age)

 38          20 LOAD_CONST               5 ('ok')
             22 RETURN_VALUE
None
-1
{}
2
{}
12
{'name': 'zy'}