lla

Interpreter for a basic logic language, inspired by two-element boolean algebra.

Demo

Here's a quick demo, based on the example that prompted its creation:

>>> from lla.interpreter import Interpreter
>>> variables = {
...     'ssh': True,
...     'website_up': True,
...     'search_up': False,
...     'elasticsearch.http': False,
...     'elasticsearch.process': True,
... }
>>> interpreter = Interpreter(variables)
>>> interpreter.run('ssh & website_up')
True
>>> interpreter.run('ssh & website_up & search_up')
False
>>> interpreter.run('!search_up & !elasticsearch.http & elasticsearch.process')
True
>>> interpreter.run('undefined_variable')
Traceback (most recent call last):
    ...
lla.interpreter.UndefinedVariableException: Undefined variable: undefined_variable

By replacing the variables dict with a class implementing __getitem__, it becomes incredibly flexible.

Overview

Here's the gist of it:

1. All variables are booleans.
2. You can't define variables in the language itself, but it be provided a dict or any object implementing __getitem__.
3. Only fully-resolvable statements are supported. a. Anything else raises a Python exception.
4. You provide the interpreter a single statement and it gets simplified to a single boolean value, which is then returned.

Dependencies

In theory, all you need is Python 3.6+.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/duckinator/lla.

The code for lla is available under the MIT License.