如何在当前范围内动态执行函数并将其添加为调用函数的属性? [英] How can I dynamically execute function in current scope and add it as property of the calling function?

问题描述

我有一些类似这样的代码:

I have some code like this:

def f1():
  <some stuff here>
.
.
.

@mylib.codegen
def f2(args):
  f1()
  <some more stuff here>

mylib.py:

def codegen(fn):
  src = inspect.getsource(fn)
  original_ast = ast.parse(src)
  new_ast = transform_ast(original_ast)
  code_obj = compile(new_ast, '<auto-generated>', 'exec')
  myscope = {}
  exec code_obj in myscope
  fn.generated_fn = myscope['name']   # Where name is the binding created by execing code_obj

总而言之，mylib.codegen是一个装饰器，它解析f的代码，基于f的ast创建另一个函数的ast，执行生成函数的代码以获取可调用函数并将可调用函数设置为f的属性. f.这意味着当第一次导入f2时，f2动态获取另一个函数作为其自身的属性.

To summarize, mylib.codegen is a decorator which parses code of f, creates an ast of another function based on ast of f, execs code of generated function to get a callable function and sets callable function as a property of f. That means when f2 is imported the first time, f2 dynamically gets another function as property of itself.

生成的函数还需要调用f1，但是在myscope中找不到f1.如果Python以某种方式允许内联，并且我已经内联了mylib.codegen的代码，一切都会好起来的，但是我认为Python不允许内联代码. 我该如何设置以便在调用者函数的命名空间中执行生成的代码对象?

Generated function also needs to call f1 but it can't find f1 in myscope. If somehow Python allowed inlining, and I had inlined code of mylib.codegen, everything would have been fine but I don't think Python allows inlining of code. How do I set things up so that generated code object is execed in namespace of caller function?

推荐答案

fn.func_globals包含给定函数的全局名称空间；您将需要它来执行转换并重新编译的代码对象:

The fn.func_globals contains the global namespace for a given function; you'll need it to be able to exec the transformed and recompiled code object:

myscope = {}
myscope.update(fn.func_globals)

请勿直接使用fn.func_globals；您不想覆盖该命名空间中的项目.

Do not use fn.func_globals directly; you wouldn't want to overwrite items in that namespace.

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