A simple, thrown-together library for displaying a truth table for boolean expressions.
You can use the provided command-line tool to display an arbitrary expression:
$ truth "A && B || C"
Expression:
A && B || C
A B C | =
---------+---
f f f | f
t f f | f
f t f | f
t t f | t
f f t | t
t f t | t
f t t | t
t t t | t
Or, you can do it programmatically:
require 'truth'
table = Truth::Table.new("A && B || C")
table.display
You can also generate
Karnaugh maps (K-maps).
From the command-line, just pass -k to the truth
tool to have it
display both the truth table and the K-map:
$ truth -k "A && B || C"
Expression:
A && B || C
A B C | =
---------+---
f f f | f
t f f | f
f t f | f
t t f | t
f f t | t
t f t | t
f t t | t
t t t | t
AB
00 01 11 10
+--+--+--+--+
C 0 |0 |0 |1 |0 |
+--+--+--+--+
1 |1 |1 |1 |1 |
+--+--+--+--+
Or, programmatically:
require 'truth'
table = Truth::Table.new("A && B || C")
table.kmap.display
The parser is simplistic, but supports the following boolean operations:
- NOT:
!A
- AND:
A && B
- OR:
A || B
- XOR:
A ^^ B
The ||
and ^^
operators have the same precedence, with &&
being
higher than either, and !
being highest of all.
Parentheses may be used to group expressions.
This was thrown together as a proof of concept, and is being made public primarily because I spent time on it and figured it might help someone else. There are not currently any tests (shame on me!) but I would gladly accept a pull request if someone is feeling ambitious.
This code is written by Jamis Buck jamis@jamisbuck.org and is distributed under the MIT license (see the MIT-LICENSE file).