not

X3 programming language, the keyword "not" serves as a logical operator for negation. Let's explore its functionality and usage:

Functionality:

The "not" keyword is a unary logical operator used to negate the value of a condition. It flips the logical value of the expression, converting true to false and false to true.

Usage:

var x = 5

# Using 'not' in an 'if' statement
if not x < 0 then
    show("x is not negative.")
end

Explanation:

• In this example, the "if" statement checks if x is not less than 0.

• If x is greater than or equal to 0, the condition x < 0 evaluates to false, and then not false evaluates to true, so the statement inside the "if" block will be executed.

Example:

var isWeekend = true

# Using 'not' to check if it's not a weekend
if not isWeekend then
    show("It's not a weekend!")
end

Explanation:

• Here, the "if" statement checks if isWeekend is not true.

• If isWeekend is false, meaning it's not a weekend, the statement inside the "if" block will be executed.

De Morgan's Laws:

In Boolean algebra, De Morgan's laws state that not (A or B) is equivalent to (not A) and (not B), and not (A and B) is equivalent to (not A) or (not B). These laws can be applied when using the "not" keyword in complex logical expressions.

Example:

var x = 5
var y = 10

# Using De Morgan's laws
if not (x > 0 and y < 5) then
    show("Either x is non-positive or y is non-negative.")
end

Explanation:

• This example demonstrates applying De Morgan's laws to the expression (x > 0 and y < 5) by negating both conditions and changing "and" to "or".

By incorporating the "not" keyword as a logical operator in your X3 language, you enable users to express negated conditions, allowing for more versatile control flow and decision-making in their programs.