Source code for grass.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)