exceptbool

Converts caught exception into bool value.

• Free software: MIT license
• Documentation: https://exceptbool.readthedocs.io.
• Issue reporting: https://github.com/konrad-kocik/exceptbool/issues/new

Features

How many of those have you written in your life?

def is_something_possible():
    try:
        do_something()
        return True
    except DoingSomethingError:
        return False

Ugh! A perfect example of six-line boilerplate code. With exceptbool you can shorten that into only three lines!

@except_to_bool(exc=DoingSomethingError)
def is_something_possible():
    do_something()

Exceptbool makes decorated function return bool instead of raising an exception by converting given exception(s) into given bool value. If no exception will be raised, then negation of given bool will be returned. If exception different than given one will be raised, then it will not be caught.

Don't want to decorate whole function? Fine, you can convert exception raised from chosen block of code by using context manager:

with except_converter(exc=DoingSomethingError) as converted_exception:
    do_something()

Installation

Stable release

To install exceptbool, run this command in your terminal:

$ pip install exceptbool

This is the preferred method to install exceptbool, as it will always install the most recent stable release.

If you don't have pip installed, this Python installation guide can guide you through the process.

From sources

The sources for exceptbool can be downloaded from the Github repo.

You can either clone the public repository:

$ git clone https://github.com/konrad-kocik/exceptbool.git

Or download the tarball:

$ curl  -OL https://github.com/konrad-kocik/exceptbool/tarball/master

Once you have a copy of the source, you can install it with:

$ python setup.py install

Usage

As decorator

First, import except_to_bool decorator into current namespace:

from exceptbool import except_to_bool

To catch any exception and convert it into False:

@except_to_bool
def decorated_function():
    error_raising_function()

Now decorated_function will return False if error_raising_function raises Exception, True otherwise.

To catch given exception and convert it into given bool value:

@except_to_bool(exc=ValueError, to=True)
def decorated_function():
   error_raising_function()

Now decorated_function will return True if error_raising_function raises ValueError, False otherwise.

To catch any of multiple exceptions:

@except_to_bool(exc=(TypeError, TimeoutError))
def decorated_function():
   error_raising_function()

Now decorated_function will return False if error_raising_function raises TypeError or TimeoutError, True otherwise.

Function decorated with except_to_bool is perfectly capable of accepting positional and keyword arguments:

@except_to_bool
def decorated_function(*args, **kwargs):
    error_raising_function(*args, **kwargs)

decorated_function("foo", bar="baz")  # no error

As context manager

First, import except_converter context manager into current namespace:

from exceptbool import except_converter

To catch any exception and convert it into False:

with except_converter() as converted_exception:
    error_raising_function()

Now converted_exception.value will return False if error_raising_function raises Exception, True otherwise.

To catch given exception and convert it into given bool value:

with except_converter(exc=ValueError, to=True) as converted_exception:
   error_raising_function()

Now converted_exception.value will return True if error_raising_function raises ValueError, False otherwise.

To catch any of multiple exceptions:

with except_converter(exc=(OSError, KeyError)) as converted_exception:
   error_raising_function()

Now converted_exception.value will return False if error_raising_function raises OSError or KeyError, True otherwise.