programming-for-all-al

Chapter 5: Operators and Expressions

5.1 Arithmetic Operators

AL includes standard arithmetic operators for performing mathematical calculations:

• + (addition)
• - (subtraction)
• * (multiplication)
• / (division)

Example:

var
    total: Decimal;
    quantity: Integer;
    price: Decimal;
begin
    quantity := 10;
    price := 15.5;
    total := quantity * price; // total is 155.0
end;

5.2 Logical and Comparison Operators

Logical operators allow you to perform boolean logic operations, while comparison operators compare values:

Logical: AND, OR, NOT Comparison: =, <>, <, >, <=, >= Example:

var
    isActive: Boolean;
    count: Integer;
begin
    isActive := TRUE;
    count := 5;
    if isActive AND (count > 0) then
        Message('The record is active and count is greater than zero.');
end;

5.3 Working with Expressions

Expressions in AL can combine operators and functions to compute values. They are used in assignments, conditions, and other contexts:

var
    discountRate: Decimal;
    price: Decimal;
    finalPrice: Decimal;
begin
    discountRate := 0.1;
    price := 100;
    finalPrice := price * (1 - discountRate); // finalPrice is 90
end;