python - 有什么方法可以像Python中的C++宏函数那样替换数字吗？

Question

当我开发 C++ 应用程序时，我更喜欢使用宏函数来表示常量。它无疑增强了代码的可读性。

我搜索过在python上应用的方法，但没有找到。

如果Python语法上存在类似的函数，请告诉我如何做，如果不存在，请告诉我为什么它不存在，并结合Python的特性。

谢谢。

Answer 1

您希望非程序员能够更改这些值，所以这是一种配置？

您可以创建一个仅分配全局变量的单独文件，然后导入它，或者读取并执行它。

示例(如 https://github.com/QQuick/Opy 中使用的):

#====================================================================================================
# General options
# All options have default value False
#====================================================================================================

obfuscate_strings = True        # Don't rely on this for sensitive information
obfuscated_name_tail = '_opy_'  # Will be added to all obfuscated names to avoid clashes with plain names
plain_marker = '_opy_'          # Strings or comments containing this marker will not be obfuscated
pep8_comments = True            # If True, only inline comments of the form <blank><blank>#<blank>
                                # will be recognized, allowing # to appear in strings as long as
                                # it doesn't have that particular form



#====================================================================================================
# Extensions of files that should be obfuscated
# Typically these are files containing Python source code
# Other files are just copied to the target directory
#====================================================================================================

source_extensions = '''
py
pyx
'''



#====================================================================================================
# Extensions of files that should neither be obfuscated nor copied to the target directory
# Typically these are .pyc files, which could easily be decompiled, breaking obfuscation
#====================================================================================================

skip_extensions = '''
pyc
'''



#====================================================================================================
# Fragments that, when occuring in the path of a file, will cause this file to be ignored
# In other words, such files will neither be ofuscated nor copied
# Use this to exclude complete directories from any processing by Opy
# N.B. Use forward slashes rather than backslashes, also on Windows!
#====================================================================================================

skip_path_fragments = '''
test_dummy
'''



#====================================================================================================
# Modules in sys.path containing identifiers that should not be obfuscated
# Typically these are installed standard or 3rd party modules of which you have no source code
# Use dotted names if needed, e.g. include both matplotlib and matplotlib.pyplot
#====================================================================================================

external_modules = '''
re
os
sys
errno
keyword
importlib
random
codecs
shutil
'''



#====================================================================================================
# Relative path + name of Python source files containing identifiers that should not be obfuscated
# Typically these are human readable settings files loaded and exec'ed at runtime by your program
# Do not use this facility for files that are imported, that's what external_modules is for
# Also don't use it to keep the original file name for your main module, that what plain_names is for
#====================================================================================================

plain_files = '''
opy_config.txt
'''



#====================================================================================================
# Extra identifiers and module names (as opposed to contents) that should not be obfuscated
# Probably at least the names of your main modules (so not their filenames) go here
# If e.g. your main module is in my_main_module.py, include my_main_module in plain_names
#====================================================================================================

plain_names = '''
opy
poly_walker_test
'''

通过以下代码读取:

# =========== Read config file

    try:
        configFile = open (configFilePath)
    except Exception as exception:
        print (exception)
        printHelpAndExit (1)

    exec (configFile.read ())
    configFile.close ()

    def getConfig (parameter, default):
        try:
            return eval (parameter)
        except:
            return default

    obfuscateStrings = getConfig ('obfuscate_strings', False)
    asciiStrings = getConfig ('ascii_strings', False)
    obfuscatedNameTail = getConfig ('obfuscated_name_tail', '_{}_'.format (programName))
    plainMarker = getConfig ('plain_marker', '_{}_'.format (programName))
    pep8Comments = getConfig ('pep8_comments', True)
    sourceFileNameExtensionList = getConfig ('source_extensions.split ()', ['py', 'pyx'])
    skipFileNameExtensionList = getConfig ('skip_extensions.split ()', ['pyc'])
    skipPathFragmentList = getConfig ('skip_path_fragments.split ()', [])
    externalModuleNameList = getConfig ('external_modules.split ()', [])
    plainFileRelPathList = getConfig ('plain_files.split ()', [])
    extraPlainWordList = getConfig ('plain_names.split ()', [])