有没有一种方法可以缩进Python而不会影响代码

这是一个很好的用例，像我们这样的技术艺术家在Maya中构建UI时每天都要面对。

对于基于PyMEL的UI：

这是内置在PyMEL中的。您不必创建上下文管理器。布局命令本身是上下文管理器。您只需with在每个布局命令调用之前添加一个关键字，如下所示：

# Do this when using PyMEL for your UI code
import pymel.core as pm

# ...

with pm.rowColumnLayout( numberOfColumns = 5 ):
    pm.text( label="", width = 1 )
    pm.text( label="Column 1", enable = False, width = 250 )
    pm.text( label="", width = 1 )
    pm.text( label="Column 2", enable = False, width = 250 )
    pm.text( label="", width = 1 )

    pm.text( label="" )

    with pm.rowColumnLayout( numberOfColumns = 4 ):
        pm.text( label="   Input data:", align="left" )
        pm.text( label="" )
        pm.text( label="" )
        pm.text( label="" )
        pm.textField( text = "Text here" )
        pm.text( label="" )
        pm.text( label="" )
        pm.text( label="" )        

    pm.text( label="" )
    with pm.rowColumnLayout( numberOfColumns = 4 ):
        with pm.rowColumnLayout( numberOfColumns = 5 ):
            pm.radioButton( label = "Read file from path", width = 100 )
            pm.text( label="" )
            pm.button( label = "Browse" )
            pm.text( label="" )
            pm.button( label = "Validate" )

        pm.text( label="" )
        pm.text( label="" )
        pm.text( label="" )

对于基于maya.cmds的UI：

一种快速的解决方案是制作一个虚拟的上下文管理器。你可以做这样的事情

# Do this when using Maya's cmds for your UI code
import maya.cmds as cmds

# ...

from contextlib import contextmanager
@contextmanager
def neat_indent():
    # OPTIONAL: This is also an opportunity to do something before the block of code runs!
    try:
        # During this is where your indented block will execute
        # Leave it empty
        yield
    finally:
        # OPTIONAL: This is where you can write code that executes AFTER your indented block executes.
        pass

这样，您的代码不必更改太多。只需with在每个预期缩进的开头添加您的上下文管理器功能和关键字！

cmds.rowColumnLayout( numberOfColumns = 5 )
with neat_indent():
    cmds.text( label="", width = 1 )
    cmds.text( label="Column 1", enable = False, width = 250 )
    cmds.text( label="", width = 1 )
    cmds.text( label="Column 2", enable = False, width = 250 )
    cmds.text( label="", width = 1 )

    cmds.text( label="" )

    cmds.rowColumnLayout( numberOfColumns = 4 )
    with neat_indent():
        cmds.text( label="   Input data:", align="left" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.textField( text = "Text here" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.setParent( ".." )

    cmds.text( label="" )
    cmds.rowColumnLayout( numberOfColumns = 4 )
    with neat_indent():
        cmds.rowColumnLayout( numberOfColumns = 5 )
        with neat_indent():
            cmds.radioButton( label = "Read file from path", width = 100 )
            cmds.text( label="" )
            cmds.button( label = "Browse" )
            cmds.text( label="" )
            cmds.button( label = "Validate" )
            cmds.setParent( ".." )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.setParent( ".." )
    cmds.setParent( ".." )

我们创建的上下文管理器neat_indent()，还使您有机会编写包装缩进块的代码。这里的一个实际例子是，在每个缩进的结尾处，您都会发现自己在写作py.setParent("..")。您可以将其放入finally上下文管理器的部分：

from contextlib import contextmanager
@contextmanager
def neat_indent(parent=None):
    # OPTIONAL: This is also an opportunity to do something before the block of code runs!
    try:
        # During this is where your indented block will execute
        # Leave it empty
        yield
    finally:
        # OPTIONAL: This is where you can write code that executes AFTER your indented block executes.
        if parent:
            cmds.setParent(parent)

您的代码现在更有意义了：

cmds.rowColumnLayout( numberOfColumns = 5 )
with neat_indent(".."):
    cmds.text( label="", width = 1 )
    cmds.text( label="Column 1", enable = False, width = 250 )
    cmds.text( label="", width = 1 )
    cmds.text( label="Column 2", enable = False, width = 250 )
    cmds.text( label="", width = 1 )

    cmds.text( label="" )

    cmds.rowColumnLayout( numberOfColumns = 4 )
    with neat_indent(".."):
        cmds.text( label="   Input data:", align="left" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.textField( text = "Text here" )
        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )        

    cmds.text( label="" )
    cmds.rowColumnLayout( numberOfColumns = 4 )
    with neat_indent(".."):
        cmds.rowColumnLayout( numberOfColumns = 5 )
        with neat_indent(".."):
            cmds.radioButton( label = "Read file from path", width = 100 )
            cmds.text( label="" )
            cmds.button( label = "Browse" )
            cmds.text( label="" )
            cmds.button( label = "Validate" )

        cmds.text( label="" )
        cmds.text( label="" )
        cmds.text( label="" )

上下文管理器功能强大。在这篇文章中，我使用了标准库模块中的contextmanager装饰器contextlib。您可以在此处阅读有关此技术的信息。关于这里with一般。

同样，出于这个目的（目的之一），使Maya中的UI开发更加清洁，并且使用Pythonic @theodox创建了mGui模块。一探究竟。