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import inspect
from optparse import OptionParser
class UserError(Exception):
pass
def add_dict(name, **kwargs):
def decorator(func):
setattr(func, name, kwargs)
return func
return decorator
def types(**kwargs):
return add_dict('_types', **kwargs)
def helps(**kwargs):
return add_dict('_helps', **kwargs)
def get_function_parser(function):
"""Generate an OptionParser for a function.
Defaults come from the parameter defaults. Types are inferred from the
default, or may be specified using the types decorator.
Help may be specified using the helps decorator.
"""
parser = OptionParser()
args, ignore, ignored, defaults = inspect.getargspec(function)
if defaults is not None:
defaults_dict = dict(zip(args, defaults))
else:
defaults_dict = {}
arg_types = getattr(function, '_types', {})
for arg in args:
arg_type = arg_types.get(arg)
if arg_type is None:
arg_type = defaults_dict.get(arg)
if arg_type is None:
continue
arg_type = type(arg_type)
arg_help = getattr(function, '_helps', {}).get(arg)
if arg_help is not None:
arg_help += ' Default: %default.'
parser.add_option('--%s' % arg, type=arg_type, help=arg_help)
option_defaults = dict(
(key, value) for key, value in defaults_dict.items()
if parser.defaults.get(key, '') is None)
parser.set_defaults(**option_defaults)
return parser
def parse_args(command, args):
"""Return the positional arguments as a dict."""
# TODO: implement!
if len(args) != 0:
raise UserError('Too many arguments.')
return {}
def run_from_args(command, cmd_args):
"""Run a command function using the specified commandline arguments."""
parser = get_function_parser(command)
options, args = parser.parse_args(cmd_args)
kwargs = parse_args(command, args)
kwargs.update(options.__dict__)
command(**kwargs)
def run_subcommand(subcommands, argv):
"""Run a subcommand as specified by argv."""
if len(argv) < 1:
raise UserError('Must supply a command: %s.' %
', '.join(subcommands.keys()))
try:
command = subcommands[argv[0]]
except KeyError:
raise UserError('%s invalid. Valid commands: %s.' %
(argv[0], ', '.join(subcommands.keys())))
run_from_args(command, argv[1:])
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