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Source code for pydispatch.robustapply

"""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'


[docs]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 receiver type %s %s' % (receiver, type(receiver))) return receiver, getattr(receiver, func_code), 0
[docs]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. for arg in named.keys(): if arg not in acceptable: del named[arg] return receiver(*arguments, **named)

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