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 list(named): if arg not in acceptable: del named[arg] return receiver(*arguments, **named)