Question

I know when using Groovy closures, I can change the delegate on the closure so function calls made within the closure could be defined externally.

我能否在沙捞?

具体来说,如果你采用以下守则:

def configure():
  build()

def wrap(function):
  def build():
    print  build 

  function()

wrap(configure)

我喜欢印刷(只改动<代码>wrap()。

一些说明:

I don t want to pass functions into configure() since there may be a large number of functions that can be called by configure().

我也不想在全球界定这些职能,因为再次可能有许多职能可以通过<代码>configure(<>configure(>),我不想污染全球名称空间。

Answer 1

Whether or not is a good way to do this is debatable, but here s a solution that doesn t modify the global namespace.

def configure():
  build()

def wrap(f):
  import new
  def build():
    print  build 

  new.function(f.func_code, locals(), f.func_name, f.func_defaults, f.func_closure)()

wrap(configure)

见https://stackoverflow.com/questions/1142068/how-to-modification-the- local-namespace-in-python。 • 如何在python修改当地名称空间

Answer 2

This is doable without metaprogramming. Have configure take the build function as a parameter:

def default_build():
    print "default build"

def configure(build_func=None):
    build_func = build_func or default_build
    build_func()

def wrap(func):
    def build():
        print "wrap build"

    func(build)

wrap(configure)

这样就明确了<代码>configure功能的改变。

您可与名称空间相左<代码>configure。同样,我理解格罗维耶所做的事情:

def build():
    print "default build"

def configure():
    build()

def wrap(func):
    def _build():
        print "wrap build"

    old_build = func.func_globals[ build ]
    func.func_globals[ build ] = _build
    func()
    func.func_globals[ build ] = old_build

Answer 3

如果你感觉到cra和some,请看。

基本上,这一想法是修改功能的密码(使用<条形码><>条/条码>模块),并以并非严格意义上的当地范围的所有参考资料取代。 • 说明基本概念(在沙尔-普鲁多编码):

code = byteplay.extractcode(function)
newbytecode = []

for opcode, arg in code.code:
    if opcode in (NONLOCAL_CODES):
        opcode = LOCAL_EQUIVALENT

    newbytecode.append((opcode, arg))

code.code = newbytecode

return code.to_code()

It s slightly more complicated than that, but the article provides some great information.

He also recommends not to use it in production. :D

Answer 4

一种方式是将<代码>build<>/code>作为全球编码,载于wrap:

def configure():
  build()

def wrap(function):
  global build
  def build():
    print  build 

  function()

wrap(configure)

然而,我没有真正建议这样做,因为它将污染名称空间。

Answer 5

You need to use the global statement so that build() is defined in the global scope, try the following:

def wrap(function):
  global build
  def build():
    print  build 

  function()

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