welchbj/tt

Synopsis

tt (truth table) is a library aiming to provide a Pythonic toolkit for working with Boolean expressions and truth tables. Please see the project site for guides and documentation, or check out bool.tools for a simple web application powered by this library.

Installation

tt is tested on CPython 3.6, 3.7, and 3.8. You can get the latest release from PyPI with:

pip install ttable

Features

Parse expressions:

>>> from tt import BooleanExpression
>>> b = BooleanExpression('A impl not (B nand C)')
>>> b.tokens
['A', 'impl', 'not', '(', 'B', 'nand', 'C', ')']
>>> print(b.tree)
impl
`----A
`----not
     `----nand
          `----B
          `----C

Evaluate expressions:

>>> b = BooleanExpression('(A /\ B) -> (C \/ D)')
>>> b.evaluate(A=1, B=1, C=0, D=0)
False
>>> b.evaluate(A=1, B=1, C=1, D=0)
True

Interact with expression structure:

>>> b = BooleanExpression('(A and ~B and C) or (~C and D) or E')
>>> b.is_dnf
True
>>> for clause in b.iter_dnf_clauses():
...     print(clause)
...
A and ~B and C
~C and D
E

Apply expression transformations:

>>> from tt import to_primitives, to_cnf
>>> to_primitives('A xor B')
<BooleanExpression "(A and not B) or (not A and B)">
>>> to_cnf('(A nand B) impl (C or D)')
<BooleanExpression "(A or C or D) and (B or C or D)">

Or create your own:

>>> from tt import tt_compose, apply_de_morgans, coalesce_negations, twice
>>> b = BooleanExpression('not (not (A or B))')
>>> f = tt_compose(apply_de_morgans, twice)
>>> f(b)
<BooleanExpression "not not A or not not B">
>>> g = tt_compose(f, coalesce_negations)
>>> g(b)
<BooleanExpression "A or B">

Exhaust SAT solutions:

>>> b = BooleanExpression('~(A or B) xor C')
>>> for sat_solution in b.sat_all():
...     print(sat_solution)
...
A=0, B=1, C=1
A=1, B=0, C=1
A=1, B=1, C=1
A=0, B=0, C=0

Find just a few:

>>> with b.constrain(A=1):
...     for sat_solution in b.sat_all():
...         print(sat_solution)
...
A=1, B=0, C=1
A=1, B=1, C=1

Or just one:

>>> b.sat_one()
<BooleanValues [A=0, B=1, C=1]>

Build truth tables:

>>> from tt import TruthTable
>>> t = TruthTable('A iff B')
>>> print(t)
+---+---+---+
| A | B |   |
+---+---+---+
| 0 | 0 | 1 |
+---+---+---+
| 0 | 1 | 0 |
+---+---+---+
| 1 | 0 | 0 |
+---+---+---+
| 1 | 1 | 1 |
+---+---+---+

And much more!

License

tt uses the MIT License.