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In some circumstances you might like to have the configuration file
for your Python program actually be another Python program, especially
if you want your users to be able to write really cool config files.
At first glance the eval() statement looks like a nice
way to do this, but unfortunatley it won't work because
import isn't an expression, it's a statement.
>>> config_file = "config"
>>> eval("import " + config)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
NameError: name 'config' is not defined
You can get around this however with the ihooks
library. First, create a config file called config.py
with the following.
class Config:
some_config_dictionary = {"option" : "Hello Config"}
Then you can import the config as per the following
import ihooks, os
def import_module(filename):
loader = ihooks.BasicModuleLoader()
path, file = os.path.split(filename)
name, ext = os.path.splitext(file)
module = loader.find_module_in_dir(name, path)
if not module:
raise ImportError, name
module = loader.load_module(name, module)
return module
def config_example():
config = import_module("config.py").Config
print config.some_config_dictionary["option"]
if __name__ == "__main__":
config_example()
All going well, you should print out Hello,
Config!
posted at: Wed, 02 Mar 2005 20:18 | in /code/python | permalink | add comment (0 others)
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