我正在使用PyMel为Maya编写一些代码,并尝试在我的rig类中创建一些属性来包装一些PyMel代码。所有属性的代码都非常相似,所以我认为这将是一个使用闭包的好地方。
import pymel.core as pm
import riggermortis.utils as utils
class RigModule(object):
def __init__:
# blah blah irrelevant code here
pass
def createRootProperty(attrName):
def getter(self):
return pm.getAttr(self.root+'.'+attrName)
def setter(self, nodeToLink):
if self.root.hasAttr(attrName):
pm.setAttr(self.root+'.'+attrName, nodeToLink)
else:
utils.linkNodes(self.root, nodeToLink, attrName)
return property(fget=getter,fset=setter)
hookConstraint = createRootProperty('hookConstraint')
unhookTarget = createRootProperty('unhookTarget')
moduleGrp = createRootProperty('moduleGrp')
hookGrp = createRootProperty('hookGrp')
它在功能上是有效的,但是Eclipse/PyDev告诉我,我的'createRootProperty‘函数需要'self’作为它的第一个参数,所以我想知道我所做的是不是不正确。
发布于 2018-06-07 05:14:05
对于您正在做的事情,除了干净之外,并不真正需要闭包。linter认为它是一个格式不正确的成员函数,即使它正在执行您想要的操作。
您只需移动类作用域的函数,linter就会停止抱怨--您可以使用下划线重命名函数,这样就不会有人意外地认为它是一个工具而不是一块基础设施。
如果您希望经常这样做,您可以将其自动化到一个元类中,该元类从class字段中读取名称列表,并根据需要创建属性。该策略here有一个更详细的示例,但本质上,元类将在定义类时获得类字典的副本,并且它有机会在编译之前扰乱定义。您可以在该步骤中轻松创建属性:
def createRootProperty(name):
# this is a dummy, but as long as
# the return from this function
# is a property descriptor you're good
@property
def me(self):
return name, self.__class__
return me
class PropertyMeta(type):
# this gets called when a class using this meta is
# first compiled. It gives you a chance to intervene
# in the class creation project
def __new__(cls, name, bases, properties):
# if the class has a 'PROPS' member, it's a list
# of properties to add
roots = properties.get('PROPS', [])
for r in roots:
properties[r] = createRootProperty(r)
print ("# added property '{}' to {}".format(r, name))
return type.__new__( cls, name, bases, properties)
class RigModule(object):
__metaclass__ = PropertyMeta
PROPS = ['arm', 'head', 'leg']
def __init__(self):
pass
test = RigModule()
print test.arm
class Submodule(RigModule):
# metaclass added properties are inheritable
pass
test2 = Submodule()
print test2.leg
class NewProperties(RigModule):
# they can also be augmented in derived classes
PROPS = ['nose', 'mouth']
print NewProperties().nose
print NewProperties().arm
# added property 'arm' to RigModule
# added property 'head' to RigModule
# added property 'leg' to RigModule
# ('arm', <class '__main__.RigModule'>)
# ('leg', <class '__main__.Submodule'>)
# added property 'nose' to NewProperties
# added property 'mouth' to NewProperties
# ('nose', <class '__main__.NewProperties'>)
# ('arm', <class '__main__.NewProperties'>)
元类因为增加了复杂性而得到了不好的评价--有时这是理所当然的。当一种更简单的方法可以使用时,不要使用它们。但是在这种情况下,对于样板文件的减少,它们是一个很好的工具。
https://stackoverflow.com/questions/50723957
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