Benchmarking argspec strategies

argspec_benchmarks.py

from __future__ import print_function  # want same code for py2/py3

import inspect
import sys

has_signature = (sys.version_info[:2] >= (3, 3))


BAD_ARGS, GOOD_ARGS = (1, 2)


def fun_good(arg1, arg2, arg3='default'):
    pass

def fun_bad(arg1, arg2, arg3='default'):
    raise TypeError()


# eval setup
shadows = {}
for fun in [fun_good, fun_bad]:
    argspec = inspect.getargspec(fun_good)
    signature = inspect.formatargspec(*argspec)[1:-1]  # remove parens
    src = "lambda {}: None".format(signature)
    shadow = eval(src)
    shadows[fun] = shadow


def with_eval(fun, *args, **kwargs):
    shadow = shadows[fun]
    try:
        fun(*args, **kwargs)
        return GOOD_ARGS
    except TypeError:
        try:
            shadow(*args, **kwargs)
            return GOOD_ARGS
        except TypeError:
            return BAD_ARGS


def with_callargs(fun, *args, **kwargs):
    try:
        fun(*args, **kwargs)
        return GOOD_ARGS
    except TypeError:
        try:
            inspect.getcallargs(fun_good, *args, **kwargs)
            return GOOD_ARGS
        except TypeError:
            return BAD_ARGS


def with_trace(fun, *args, **kwargs):
    try:
        fun(*args, **kwargs)
    except TypeError:
        if len(inspect.trace()) == 1:
            return BAD_ARGS
    return GOOD_ARGS


if has_signature:

    # signature setup
    signatures = {}
    for fun in [fun_good, fun_bad]:
        signatures[fun] = inspect.signature(fun)

    def with_signature(fun, *args, **kwargs):
        try:
            fun(*args, **kwargs)
            return GOOD_ARGS
        except TypeError:
            signature = signatures[fun]
            try:
                signature.bind(*args, **kwargs)
                return GOOD_ARGS
            except TypeError:
                return BAD_ARGS


if __name__ == '__main__':
    import timeit
    number = 1000
    extra_imports = "fun_good, fun_bad, GOOD_ARGS, BAD_ARGS"

    testers = ["eval", "callargs", "trace"]
    if has_signature:
        testers.append("signature")

    for tester in testers:
        test = """
            assert tester(fun_good, 1, 2) == GOOD_ARGS
            assert tester(fun_good, 1) == BAD_ARGS
            assert tester(fun_bad, 1, 2) == GOOD_ARGS
            assert tester(fun_bad, 1) == BAD_ARGS
        """
        result = timeit.timeit(test,
            setup="from __main__ import with_%s as tester, %s" % (
                tester, extra_imports),
            number=number,
        )
        adjust = max(map(len, testers))
        print("%s: %s" % (tester.rjust(adjust), result))