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- """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.
- """
- import sys
- if sys.hexversion >= 0x3000000:
- im_func = '__func__'
- im_self = '__self__'
- im_code = '__code__'
- func_code = '__code__'
- else:
- im_func = 'im_func'
- im_self = 'im_self'
- im_code = 'im_code'
- func_code = 'func_code'
-
- 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__'):
- # 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, getattr(getattr(receiver, im_func), func_code), 1
- elif not hasattr( receiver, func_code):
- raise ValueError('unknown reciever type %s %s'%(receiver, type(receiver)))
- return receiver, getattr(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 name in named:
- 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.
- named = dict([(k,v) for k,v in named.items() if k in acceptable])
- return receiver(*arguments, **named)
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