Truthy

Find nuget package here.

What is truthy anyway?

Well, think of truth table you just invented, you put your 1s and 0s and Truthy figures out which formula works for the table.

A	B	C
0	0	1
1	0	1
1	1	0
0	1	0

If you create the above table with Truthy, it will know what to do so that your table makes sense. Also, Truthy has implementations for the following logical gates: and, or, not, xor, nand, nor, xnor and a special or.

Where can I use it?

• Access matrices are a good example;
• Other examples are just day-to-day comparisons you do with booleans in your code.

Let your imagination make good use of Truthy.

Usage

Every functionality is under Truthy namespace. Some methods throw an exception, the TruthyException.

Truth Table

To create a truth table, you do as follows:

var t = new TruthTable(2);

2 is the number of terms in the truth table. The minimum number of terms is 2 and the maximum is 6. If you violate any of the limits, TruthyException will be raised.

To add a new row, you do as follows:

var t = new TruthTable(2);
t.AddRow(1, 1, 0);

For a truth table of n terms, the rows take n+1 terms, where +1 is the result of the operation for such row. TruthyException will be raised if:

• There are already enough rows for the defined truth table;
• You try to add equal rows;
• You try to add a row with m terms, where m != n + 1.

After you have defined your truth table and added your rows, you can check boolean values against it as follows:

var t = new TruthTable(2);
t.AddRow(1, 1, 0);

t.Check(2+2==4, 3+3==6) // > False
t.Check(2+2==1, 3+3==6) // > True

For a truth table of n terms, you check n terms.

Beware of the behaviour of Truthy, see the following example to understand.

var t = new TruthTable(2);
t.AddRow(1, 1, 0); // the other combinations will evaluate to True
t.Check(true, false) // > True

var u = new TruthTable(2);
u.AddRow(1, 1, 0);
u.AddRow(1, 0, 1);

u.Check(true, true) // > False
u.Check(true, false) // > True

// the other combinations will evaluate to True
u.Check(false, false) // > True
u.Check(false, true) // > True


var w = new TruthTable(2);
w.AddRow(1, 1, 0);
w.AddRow(1, 0, 0);
w.AddRow(0, 1, 1);

w.Check(true, true) // > False
w.Check(true, false) // > False
w.Check(false, true) // > True

// the other combinations will evaluate to False
u.Check(false, false) // > False

The tricks to master it are:

• The first row you add is determinant, take table t, if the first row was equal to 1, the the rest would be False;
• if there are more 0s than 1s explicitly (like table w), every combination that equals 0 and others not specified will evaluate to 0, which means, it could be simplified;
• if there are more 1s than 0s explicitly, every combination that equals 1 and others not specified will evaluate to 1.

At last, if you wish to know the formula, just call .ToString()

var t = new TruthTable(2);
t.AddRow(1, 1, 0); // the other combinations will evaluate to True
t.Check(true, false) // > True

t.ToString() // > (~A+~B)

Logical Gates

The logical gates are all found in the Gates class, but there are also extension methods for booleans. All operations support multiple terms and accept a minimum of 2 terms, except .Not() which accepts only 1 term.

.And is equivalent to &&. Operation is True if every term is True.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.And(b) // > True
a.And(b, c) // > False

.Or is equivalent to ||. Operation is True if any term is True.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Or(b) // > True
a.Or(b, c) // > True
Gates.Or(c, c) // > False

.Not inverts the value.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Not() // > False
Gates.Not(b) // > False
Gates.Not(c) // > True

.Xor is the exclusive OR, the operation is true if the terms are different. XOR is a binary operation, which means that if you test multiple terms, XOR will be applied for every two terms. Example: 3 terms (a, b and c), first, we do a XOR b, and then (a XOR b) XOR c.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Xor(b) // > False
a.Xor(c) // > True

.Nand is the inverse of AND operation.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Nand(b) // > False
a.Nand(b, c) // > True

.Nor is the inverse of OR operation.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Nor(b) // > False
a.Nor(b, c) // > False
Gates.Nor(c, c) // > True

.Xnoris the inverse of XOR operation.

var a = (2+2==4)
var b = (2+1==3)
var c = (2+1==5)

a.Xnor(b) // > True
a.Xnor(c) // > False

.Sor is the Special OR. Suppose you have a base object you want to compare with other objects, so that to know if one of those objects is equal to the base object, that's where you use SOR.

int a = 1, b = 1, c = 2, d = 3;

a.Sor(b, c, d) // > True
Gates.Sor(a, c, d) // > False

Note: If you use it with your custom objects, write their .Equals() accordingly, since it is what SOR uses for comparison.