"""Robust apply mechanism
Provides a function "call", which can sort out
what arguments a given callable object can take,
and subset the given arguments to match only
those which are acceptable.
"""
def function( receiver ):
"""Get function-like callable object for given receiver
returns (function_or_method, codeObject, fromMethod)
If fromMethod is true, then the callable already
has its first argument bound
"""
if hasattr(receiver, '__call__'):
# receiver is a class instance; assume it is callable.
# Reassign receiver to the actual method that will be called.
if hasattr( receiver.__call__, 'im_func') or hasattr( receiver.__call__, 'im_code'):
receiver = receiver.__call__
if hasattr( receiver, 'im_func' ):
# an instance-method...
return receiver, receiver.im_func.func_code, 1
elif not hasattr( receiver, 'func_code'):
raise ValueError('unknown reciever type %s %s'%(receiver, type(receiver)))
return receiver, receiver.func_code, 0
def robustApply(receiver, *arguments, **named):
"""Call receiver with arguments and an appropriate subset of named
"""
receiver, codeObject, startIndex = function( receiver )
acceptable = codeObject.co_varnames[startIndex+len(arguments):codeObject.co_argcount]
for name in codeObject.co_varnames[startIndex:startIndex+len(arguments)]:
if named.has_key( name ):
raise TypeError(
"""Argument %r specified both positionally and as a keyword for calling %r"""% (
name, receiver,
)
)
if not (codeObject.co_flags & 8):
# fc does not have a **kwds type parameter, therefore
# remove unacceptable arguments.
for arg in named.keys():
if arg not in acceptable:
del named[arg]
return receiver(*arguments, **named)
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