aqe/README.md

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2018-06-01 07:15:10 +00:00
## AQE: A Query Engine
This is an implementation of a knowledge base, hacked together in Python
3 (it won't work in Python 2 for reasons of modules) for now to quickly
iterate on ideas.
There are a few key points:
+ A `KnowledgeBase` contains facts.
+ A fact is a tuple: (relationship, subject, object). For example,
`('is', 'sky', 'blue')`.
+ A `KnowledgeBase` has three core methods: ask, retract, and tell.
+ The `ask` method queries the `KnowledgeBase` to ascertain whether
a fact is true. Either the subject or the object may be `None`,
in which case all satisifiable facts are returned.
+ The `retract` method tells the `KnowledgeBase` that the fact is
no longer true. If it's rainy, we might retract our fact about the
sky being blue.
+ The `tell` method tells the `KnowledgeBase` that the fact is
now true. For example, if it's rainy (and we've retracted the previous
'sky is blue' fact), we might tell the `KnowledgeBase` that
`('is', 'sky', 'grey')`.
+ A `KnowledgeBase` can also perform substitutions.
+ An action contains positive and negative preconditions, retractions,
and updates. The positive condition list contains facts that must
be true for a knowledge base, and the negative condition list contains
facts that must be false. If these preconditions hold, the retractions
are applied, followed by the updates.
+ See `test_actions.py` for an example.
### Limitations
+ Singleton facts aren't supported; that is, there is no way to make a
`KnowledgeBase` assert that there is only one relationship → subject
mapping. For example, the `KnowledgeBase` will admit that
`('is', 'shrödingers cat', 'alive')` and
`('is', 'schrödingers cat', 'dead')` are both true simultaneously.
2018-06-01 07:15:10 +00:00
### TODO
+ Rewrite in C++?