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........
  r79500 | benjamin.peterson | 2010-03-30 12:58:13 -0500 (Tue, 30 Mar 2010) | 4 lines

  add inspect.getcallargs, which binds function arguments like a normal call #3135

  Patch by George Sakkis
........
This commit is contained in:
Benjamin Peterson 2010-03-30 18:42:32 +00:00
parent e6c9d24562
commit 25cd7eb9a1
3 changed files with 270 additions and 4 deletions

View File

@ -449,6 +449,32 @@ Classes and functions
metatype is in use, cls will be the first element of the tuple.
.. function:: getcallargs(func[, *args][, **kwds])
Bind the *args* and *kwds* to the argument names of the Python function or
method *func*, as if it was called with them. For bound methods, bind also the
first argument (typically named ``self``) to the associated instance. A dict
is returned, mapping the argument names (including the names of the ``*`` and
``**`` arguments, if any) to their values from *args* and *kwds*. In case of
invoking *func* incorrectly, i.e. whenever ``func(*args, **kwds)`` would raise
an exception because of incompatible signature, an exception of the same type
and the same or similar message is raised. For example::
>>> from inspect import getcallargs
>>> def f(a, b=1, *pos, **named):
... pass
>>> getcallargs(f, 1, 2, 3)
{'a': 1, 'named': {}, 'b': 2, 'pos': (3,)}
>>> getcallargs(f, a=2, x=4)
{'a': 2, 'named': {'x': 4}, 'b': 1, 'pos': ()}
>>> getcallargs(f)
Traceback (most recent call last):
...
TypeError: f() takes at least 1 argument (0 given)
.. versionadded:: 3.2
.. _inspect-stack:
The interpreter stack

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@ -17,7 +17,7 @@ Here are some of the useful functions provided by this module:
getmodule() - determine the module that an object came from
getclasstree() - arrange classes so as to represent their hierarchy
getargspec(), getargvalues() - get info about function arguments
getargspec(), getargvalues(), getcallargs() - get info about function arguments
getfullargspec() - same, with support for Python-3000 features
formatargspec(), formatargvalues() - format an argument spec
getouterframes(), getinnerframes() - get info about frames
@ -33,6 +33,7 @@ __date__ = '1 Jan 2001'
import sys
import os
import types
import itertools
import string
import re
import dis
@ -926,6 +927,71 @@ def formatargvalues(args, varargs, varkw, locals,
specs.append(formatvarkw(varkw) + formatvalue(locals[varkw]))
return '(' + ', '.join(specs) + ')'
def getcallargs(func, *positional, **named):
"""Get the mapping of arguments to values.
A dict is returned, with keys the function argument names (including the
names of the * and ** arguments, if any), and values the respective bound
values from 'positional' and 'named'."""
spec = getfullargspec(func)
args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, ann = spec
f_name = func.__name__
arg2value = {}
if ismethod(func) and func.__self__ is not None:
# implicit 'self' (or 'cls' for classmethods) argument
positional = (func.__self__,) + positional
num_pos = len(positional)
num_total = num_pos + len(named)
num_args = len(args)
num_defaults = len(defaults) if defaults else 0
for arg, value in zip(args, positional):
arg2value[arg] = value
if varargs:
if num_pos > num_args:
arg2value[varargs] = positional[-(num_pos-num_args):]
else:
arg2value[varargs] = ()
elif 0 < num_args < num_pos:
raise TypeError('%s() takes %s %d %s (%d given)' % (
f_name, 'at most' if defaults else 'exactly', num_args,
'arguments' if num_args > 1 else 'argument', num_total))
elif num_args == 0 and num_total:
raise TypeError('%s() takes no arguments (%d given)' %
(f_name, num_total))
for arg in itertools.chain(args, kwonlyargs):
if arg in named:
if arg in arg2value:
raise TypeError("%s() got multiple values for keyword "
"argument '%s'" % (f_name, arg))
else:
arg2value[arg] = named.pop(arg)
for kwonlyarg in kwonlyargs:
if kwonlyarg not in arg2value:
try:
arg2value[kwonlyarg] = kwonlydefaults[kwonlyarg]
except KeyError:
raise TypeError("%s() needs keyword-only argument %s" %
(f_name, kwonlyarg))
if defaults: # fill in any missing values with the defaults
for arg, value in zip(args[-num_defaults:], defaults):
if arg not in arg2value:
arg2value[arg] = value
if varkw:
arg2value[varkw] = named
elif named:
unexpected = next(iter(named))
raise TypeError("%s() got an unexpected keyword argument '%s'" %
(f_name, unexpected))
unassigned = num_args - len([arg for arg in args if arg in arg2value])
if unassigned:
num_required = num_args - num_defaults
raise TypeError('%s() takes %s %d %s (%d given)' % (
f_name, 'at least' if defaults else 'exactly', num_required,
'arguments' if num_required > 1 else 'argument', num_total))
return arg2value
# -------------------------------------------------- stack frame extraction
Traceback = namedtuple('Traceback', 'filename lineno function code_context index')

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@ -1,3 +1,4 @@
import re
import sys
import types
import unittest
@ -519,10 +520,183 @@ class TestClassesAndFunctions(unittest.TestCase):
self.assertIn(('m1', 'method', D), attrs, 'missing plain method')
self.assertIn(('datablob', 'data', A), attrs, 'missing data')
class TestGetcallargsFunctions(unittest.TestCase):
def assertEqualCallArgs(self, func, call_params_string, locs=None):
locs = dict(locs or {}, func=func)
r1 = eval('func(%s)' % call_params_string, None, locs)
r2 = eval('inspect.getcallargs(func, %s)' % call_params_string, None,
locs)
self.assertEqual(r1, r2)
def assertEqualException(self, func, call_param_string, locs=None):
locs = dict(locs or {}, func=func)
try:
eval('func(%s)' % call_param_string, None, locs)
except Exception as e:
ex1 = e
else:
self.fail('Exception not raised')
try:
eval('inspect.getcallargs(func, %s)' % call_param_string, None,
locs)
except Exception as e:
ex2 = e
else:
self.fail('Exception not raised')
self.assertIs(type(ex1), type(ex2))
self.assertEqual(str(ex1), str(ex2))
del ex1, ex2
def makeCallable(self, signature):
"""Create a function that returns its locals()"""
code = "lambda %s: locals()"
return eval(code % signature)
def test_plain(self):
f = self.makeCallable('a, b=1')
self.assertEqualCallArgs(f, '2')
self.assertEqualCallArgs(f, '2, 3')
self.assertEqualCallArgs(f, 'a=2')
self.assertEqualCallArgs(f, 'b=3, a=2')
self.assertEqualCallArgs(f, '2, b=3')
# expand *iterable / **mapping
self.assertEqualCallArgs(f, '*(2,)')
self.assertEqualCallArgs(f, '*[2]')
self.assertEqualCallArgs(f, '*(2, 3)')
self.assertEqualCallArgs(f, '*[2, 3]')
self.assertEqualCallArgs(f, '**{"a":2}')
self.assertEqualCallArgs(f, 'b=3, **{"a":2}')
self.assertEqualCallArgs(f, '2, **{"b":3}')
self.assertEqualCallArgs(f, '**{"b":3, "a":2}')
# expand UserList / UserDict
self.assertEqualCallArgs(f, '*collections.UserList([2])')
self.assertEqualCallArgs(f, '*collections.UserList([2, 3])')
self.assertEqualCallArgs(f, '**collections.UserDict(a=2)')
self.assertEqualCallArgs(f, '2, **collections.UserDict(b=3)')
self.assertEqualCallArgs(f, 'b=2, **collections.UserDict(a=3)')
def test_varargs(self):
f = self.makeCallable('a, b=1, *c')
self.assertEqualCallArgs(f, '2')
self.assertEqualCallArgs(f, '2, 3')
self.assertEqualCallArgs(f, '2, 3, 4')
self.assertEqualCallArgs(f, '*(2,3,4)')
self.assertEqualCallArgs(f, '2, *[3,4]')
self.assertEqualCallArgs(f, '2, 3, *collections.UserList([4])')
def test_varkw(self):
f = self.makeCallable('a, b=1, **c')
self.assertEqualCallArgs(f, 'a=2')
self.assertEqualCallArgs(f, '2, b=3, c=4')
self.assertEqualCallArgs(f, 'b=3, a=2, c=4')
self.assertEqualCallArgs(f, 'c=4, **{"a":2, "b":3}')
self.assertEqualCallArgs(f, '2, c=4, **{"b":3}')
self.assertEqualCallArgs(f, 'b=2, **{"a":3, "c":4}')
self.assertEqualCallArgs(f, '**collections.UserDict(a=2, b=3, c=4)')
self.assertEqualCallArgs(f, '2, c=4, **collections.UserDict(b=3)')
self.assertEqualCallArgs(f, 'b=2, **collections.UserDict(a=3, c=4)')
def test_keyword_only(self):
f = self.makeCallable('a=3, *, c, d=2')
self.assertEqualCallArgs(f, 'c=3')
self.assertEqualCallArgs(f, 'c=3, a=3')
self.assertEqualCallArgs(f, 'a=2, c=4')
self.assertEqualCallArgs(f, '4, c=4')
self.assertEqualException(f, '')
self.assertEqualException(f, '3')
self.assertEqualException(f, 'a=3')
self.assertEqualException(f, 'd=4')
def test_multiple_features(self):
f = self.makeCallable('a, b=2, *f, **g')
self.assertEqualCallArgs(f, '2, 3, 7')
self.assertEqualCallArgs(f, '2, 3, x=8')
self.assertEqualCallArgs(f, '2, 3, x=8, *[(4,[5,6]), 7]')
self.assertEqualCallArgs(f, '2, x=8, *[3, (4,[5,6]), 7], y=9')
self.assertEqualCallArgs(f, 'x=8, *[2, 3, (4,[5,6])], y=9')
self.assertEqualCallArgs(f, 'x=8, *collections.UserList('
'[2, 3, (4,[5,6])]), **{"y":9, "z":10}')
self.assertEqualCallArgs(f, '2, x=8, *collections.UserList([3, '
'(4,[5,6])]), **collections.UserDict('
'y=9, z=10)')
def test_errors(self):
f0 = self.makeCallable('')
f1 = self.makeCallable('a, b')
f2 = self.makeCallable('a, b=1')
# f0 takes no arguments
self.assertEqualException(f0, '1')
self.assertEqualException(f0, 'x=1')
self.assertEqualException(f0, '1,x=1')
# f1 takes exactly 2 arguments
self.assertEqualException(f1, '')
self.assertEqualException(f1, '1')
self.assertEqualException(f1, 'a=2')
self.assertEqualException(f1, 'b=3')
# f2 takes at least 1 argument
self.assertEqualException(f2, '')
self.assertEqualException(f2, 'b=3')
for f in f1, f2:
# f1/f2 takes exactly/at most 2 arguments
self.assertEqualException(f, '2, 3, 4')
self.assertEqualException(f, '1, 2, 3, a=1')
self.assertEqualException(f, '2, 3, 4, c=5')
self.assertEqualException(f, '2, 3, 4, a=1, c=5')
# f got an unexpected keyword argument
self.assertEqualException(f, 'c=2')
self.assertEqualException(f, '2, c=3')
self.assertEqualException(f, '2, 3, c=4')
self.assertEqualException(f, '2, c=4, b=3')
self.assertEqualException(f, '**{u"\u03c0\u03b9": 4}')
# f got multiple values for keyword argument
self.assertEqualException(f, '1, a=2')
self.assertEqualException(f, '1, **{"a":2}')
self.assertEqualException(f, '1, 2, b=3')
# XXX: Python inconsistency
# - for functions and bound methods: unexpected keyword 'c'
# - for unbound methods: multiple values for keyword 'a'
#self.assertEqualException(f, '1, c=3, a=2')
class TestGetcallargsMethods(TestGetcallargsFunctions):
def setUp(self):
class Foo(object):
pass
self.cls = Foo
self.inst = Foo()
def makeCallable(self, signature):
assert 'self' not in signature
mk = super(TestGetcallargsMethods, self).makeCallable
self.cls.method = mk('self, ' + signature)
return self.inst.method
class TestGetcallargsUnboundMethods(TestGetcallargsMethods):
def makeCallable(self, signature):
super(TestGetcallargsUnboundMethods, self).makeCallable(signature)
return self.cls.method
def assertEqualCallArgs(self, func, call_params_string, locs=None):
return super(TestGetcallargsUnboundMethods, self).assertEqualCallArgs(
*self._getAssertEqualParams(func, call_params_string, locs))
def assertEqualException(self, func, call_params_string, locs=None):
return super(TestGetcallargsUnboundMethods, self).assertEqualException(
*self._getAssertEqualParams(func, call_params_string, locs))
def _getAssertEqualParams(self, func, call_params_string, locs=None):
assert 'inst' not in call_params_string
locs = dict(locs or {}, inst=self.inst)
return (func, 'inst,' + call_params_string, locs)
def test_main():
run_unittest(TestDecorators, TestRetrievingSourceCode, TestOneliners,
TestBuggyCases,
TestInterpreterStack, TestClassesAndFunctions, TestPredicates)
run_unittest(
TestDecorators, TestRetrievingSourceCode, TestOneliners, TestBuggyCases,
TestInterpreterStack, TestClassesAndFunctions, TestPredicates,
TestGetcallargsFunctions, TestGetcallargsMethods,
TestGetcallargsUnboundMethods)
if __name__ == "__main__":
test_main()