AL operators

Operators can be used in expressions to combine, investigate, and adjust values and data elements. This article describes the operators that are supported in AL.

AL operators and meaning

The following table shows the valid operators in AL.

These operators are used to perform various operations such as arithmetic, comparison, and logical operations.

General operators

Arithmetic operators

Arithmetic operators are used to perform arithmetic operations on numeric operands. The result of an arithmetic operation is a numeric value.

Comparison operators

Comparison operators are used to compare two values. The result of a comparison is a Boolean value, that is, true or false.

Logical operators

The logical operators are used on Boolean expressions

Conditional operators

Conditional operators can be used to test if a condition is met.

APPLIES TO: Business Central 2024 release wave 2 and later.

Compound operators

Compound assignment operators perform an arithmetic operation and assign the result to the same variable.

The + and the - operators can be used both as unary and binary operators. The not operator can only be used as a unary operator. All the other operators are binary.

Most of the operators can be used on different data types. The action of these operators may depend on the data type of the expression that they are used on.

Example 1

In this example, the + operator is used as a binary operator.

number + number

This returns the sum of the numbers, that is, a result of type number.

Example 2

In this example, the + operator is used as a binary operator.

string + string

This returns the concatenation of the strings, that is, a result of the type string.

Example 3

In this example, the + operator is used as a unary operator to indicate sign.

+34545  

Example 4

APPLIES TO: Business Central 2024 release wave 2 and later.

In this example, the ? : operator is used to replace a if-then-else clause.

codeunit 50122 TernaryOperator
{
    procedure Example()
    var
        myExpression: Boolean;
        myVar: Text;
    begin

        if myExpression then
            myVar := 'True';
        else
            myVar := 'False';

        myVar := myExpression ? 'True' : 'False';
    end;
}

Result type and implicit conversion

The data type of a ternary expression (Condition ? TrueExpression : FalseExpression) is determined by the true expression, even when the condition is false.

If the false expression has a different data type, its value is implicitly converted to the type of the true expression when the false expression is selected. This conversion takes place before the result of the ternary expression is assigned to its destination. Consequently, the type of the destination doesn't affect the type of the ternary expression.

The false expression must have a type that can be implicitly converted to the type of the true expression. Otherwise, a compiler error occurs. Even when the types are convertible, a runtime error occurs if the selected value can't be converted.

For example:

var
    Condition: Boolean;
    CodeValue: Code[20];
    TextValue: Text[100];
    Result: Text[250];
begin
    Condition := false;
    TextValue := 'This value is longer than 20 characters.';
    Result := Condition ? CodeValue : TextValue;
end;

In this example, the type of the ternary expression is Code[20], because CodeValue is the true expression. If TextValue is selected, its value is converted to Code[20] before the result is assigned to Result. A value longer than 20 characters can therefore cause a runtime conversion error even though Result is Text[250].

The same behavior applies to other data types. For example:

var
    UseDefault: Boolean;
    OriginalQuantity: Decimal;
    Quantity: Decimal;
begin
    UseDefault := false;
    OriginalQuantity := 0.25;
    Quantity := UseDefault ? 1 : OriginalQuantity;
end;

Because 1 is an Integer, the ternary expression has the type Integer. If OriginalQuantity is selected, its value must first be converted to Integer, even though Quantity is a Decimal. In this example, 0.25 can't be converted to Integer, so a runtime conversion error occurs. The value isn't silently truncated.

When the true and false expressions have different types, explicitly convert them to the intended common type or use an if-then-else statement to assign each value directly to the destination. For example, the following code preserves the decimal value:

if UseDefault then
    Quantity := 1
else
    Quantity := OriginalQuantity;

Operator hierarchy

Operators are organized in a hierarchy that determines the order in which the operands in a given expression are evaluated. The following list shows the order of precedence of the AL operators:

1. .(fields in records), [ ] (indexing), () (parentheses), :: (scope), @ (case-insensitive)

2. not, - (unary), + (unary)

3. *, /, div, mod, and, xor

4. +, -, or

5. >, >=, <, <=, =, <>, in

6. .. (range)

Example 1

2 + 3 * 4

This expression evaluates to 14.

Example 2

(2 + 3) * 4

This expression evaluates to 20.

Related information

Arithmetic operators
Boolean operators
Relational operators
Get started with AL