Statements and Expressions
A C/AL statement is a code instruction that when it is executed, causes operations to occur, which can change one or more variables or initiate read and write transactions to the database.
A C/AL statement is built from expressions.
A C/AL expression is a group of characters (data values, variables, arrays, operators, and functions) that can be evaluated, with the result having an associated data type. An expression is a fundamental C/AL concept. All expressions in C/AL are built from the following:
Constants
Variables
Operators
Functions
Keywords
For more information about constants, variables, operators, functions, and keywords, see Elements of C/AL Expressions.
Example 1
For this example, consider the following C/AL code.
Amount := 34 + Total;
This line of code is also called a statement. The following table illustrates how the statement can be broken into smaller elements.
| Element | Description |
|---|---|
34 + Total |
An expression. This expression consists of an arithmetic operator (+) and two arguments (34 and Total), which could also be called sub-expressions. Every valid C/AL expression can be evaluated to a specific value. |
:= |
The assignment operator. When the expression on the right side has been evaluated, this operator is used to assign or store the value in the variable on the left side. |
Amount |
A variable. Used to reference a memory location where data is stored. |
Example 2
An expression can be used as an argument for a C/AL function. Consider the following C/AL statement.
Date := DMY2DATE(31, 12, 2001);
This function takes three simple expressions as arguments: 31, 12, and 2001.
Typical Expressions
Depending on the elements in the expression, the evaluation gives you a value with a C/AL data type. The following table shows some typical expressions.
| Expression | Evaluates to | Description |
|---|---|---|
'Welcome to Hawaii' |
The string 'Welcome to Hawaii' |
Evaluates to itself. |
'Welcome ' + 'to Hawaii' |
The string 'Welcome to Hawaii' |
Evaluates to a concatenation of the two strings. |
43.234 |
The number 43.234 |
Evaluates to itself, a decimal number. |
ABS(-7234) |
The number 7234 |
A function that evaluates to a number. |
len1 < 618 |
TRUE or FALSE, depending on the value of len1 |
A comparison between a variable and a numeric constant, which evaluates to a Boolean value. |
These examples show that when C/AL expressions are evaluated, the results have a specific data type. For more information about data types, see C/AL Data Types.