Implement base types and operators

  • 12 minutes

This unit explains the different data types and operators that are used in X++.

Data types

Primitive data types are the most common data types that you will encounter. The primitive data types are: anytype, boolean, date, enum, guid, int, int64, real, str,timeOfday, and utcdatetime.

  • Date - This data type contains the day, month, and year. You can write out the date as literals by using the format day\month\year. The year must be entered as four digits. The dates that are used must be within the January 1, 1900 and December 31, 2154 range. The default value for a date data type is 1/1/1900. We recommend that you use utcDateTime instead of Date because it combines date, timeOfDay, and time zone information into a single data type.
  • Enumerations (enums) - Are a named list of literals. For example, there is an enum called NoYes, with a list of literals No and Yes. Each literal can also be represented by a number. The first literal has the number 0, the next literal has the number 1, and so on. You can also provide your own values in the enum metadata. To reference an enum value, you would use the enum name followed by two colons and the name of the literal. Considering the NoYes enum again, to reference the Yes literal, you would write NoYes::Yes.
  • GUID - This data type is a globally unique identifier (GUID) value. A GUID number is unique across all computers and networks.
  • Int - These values are 32-bit wide integer signed numbers that do not include a decimal place. There is no support for unsigned integer types.
  • Int64 - A larger, signed integer data type that works the same as the int data type, except that it is 64 bits wide compared to 32 bits. This gives the int64 type a greater range for larger numbers.
  • Real - These data types hold number values with decimals.
  • Str - This data type contains values that are a string of characters. The str value must be wrapped in double quotation marks ("text") or single quotation marks ('text').
  • TimeOfday - This data type is an integer value that represents the number of seconds that passed since midnight.
  • Utcdatetime - This data type is a combination of the date type and the timeOfday data type. The format is yyyy-mm-ddThh:mm:ss with the default value being 1900-01-01T00:00:00.

Composite data types

Along with primitive data types, there are composite data types. Composite data types include arrays, containers, classes, delegates, and tables.

  • Arrays - Contain a list of items that have the same data type. You can retrieve an element in the array with an integer index. You can use arrays in different ways. Dynamic arrays are open and fixed-length arrays specify a certain length. Partly on disk arrays can be dynamic or fixed, with an option to determine how many items are held in memory.
  • Containers - Are dynamic collections of primitive items or other containers. Containers can be useful to pass different types of values, but they are not ideal when used in processes that frequently change the size or contents.
  • Classes - Can be used as a data type to declare an instance of a class within a method.
  • Delegates - Can be defined on a method, table, form, or query. When a delegate is called, it will also call their subscriber methods. Delegates never return a value and have a default value of “no handlers added,” which means nothing is called when you call them.
  • Tables - Can be used to declare an instance of a table. Once a table instance is declared, you can manipulate the data within the table. We recommend that the table variable has the same name as the table, but you should use camel casing. For example, the table EcoResProduct would be declared by using camel casing as ecoResProduct.

User-defined data types

Extended data types (EDT) are user-defined types that are based on the boolean, int, int64, real, str, date, and container data types. EDTs can be used on variables, method parameters and field declarations, and they provide several benefits. First, they make code easier to read because the EDT name can be defined by the user. Therefore, instead of using just str, you could use an EDT called Color, which would be a more meaningful name. You can also set certain properties on the EDT that all instances of that type use. Additionally, you can create hierarchies for EDTs so an EDT can inherit the properties of a parent.

Variables

Variables are identifiers that designate a storage location where a value of a data type is stored. The size, precision, default value, and conversion functions depend on the variable's data type. Variables can be declared anywhere in a code block in a method; they do not have to be declared at the beginning of a method.

In a class, member (global) variables and local variables have different scopes. Global variables can be used throughout the instance (excluding static methods) of the class, while local variables are only available within the scope of the class method.

When you declare a variable, you will need to assign the data type and then assign the variable name. At this point, you can assign a value or leave it open to set the value. The following is an example of declaring a variable.

  1. Declare the data type inline and within code. In this example, use str for string data type.
  2. Name the variable. It must start with a letter or underscore. We recommend using meaningful names for variables that follow camel case. Camel case is where you do not capitalize the first letter of the name, but each word or abbreviation that follows the first in the phrase is capitalized (for example, purchaseOrderLine). Spacing or punctuation is not permitted.
  3. If you are assigning a value, add the equal sign and the value of the variable. String values must be either surrounded by double quotation marks or by single quotation marks for hard-coded text. It is best practice to use labels in strings, excluding the few exceptions where this is not feasible. Single quotation marks around hard-coded text suppress the best practice error that you would get for not using a label.
  4. End the declaration with a semicolon.
str customerName;

	or

str customerName = "Name";

Watch the following video to learn how to declare a variable.

Operators

Operators are used to compute values. The different types of operators include assignment operators, arithmetic operators, and relational operators.

Assignment operators can change the value of the variable or field.

Operator Description Example
= Assigns the value on the right of the equal sign to the variable on the left. Int i = 1;
+= Assigns the current variable value plus the value on the right of the equal sign. int I ; I += 1;
++ Increments the variable by 1. int I; i++;
-= Assigns the current variable value minus the expression on the right of the equal sign. int I; I -= 1;
-- Decrements the variable by 1. int I; i--;

Arithmetic operators are used to make numeric calculations.

Operator Description Example
<< The left shift operator multiplies the left value by 2 by the number of times equal to the value on the right. int a = 1 << 2 (this equals 1*2*2.)
>> The right shift operator divides the left value by 2 by the number of times equal to the value on the right. int a = 1 >> 2 (this equals 1/2/2.)
* This operator multiplies operands. int a = 1*2
/ This operator divides the left value by the right value. int a = 1/2
div The integer division operator performs an integer division of the left value and the right value. int a = 20 div 6 (This returns a division of 3 with a remainder of 2. A = 3)
mod The integer remainder operator returns the remainder of an integer of the left value and the right value. int a = 20 mod 6 (This returns a division of 3 with a remainder of 2. A = 2)
~ The not operator performs a binary not operation. int a = ~1 (This returns -2.)
& The binary AND operator performs a binary operation on the left and right value. This returns the bits in common. int a = 1 & 3 (This returns 1.)
^ The binary XOR operator performs a binary XOR operation on the left and right value. This returns the bits set in one, but not the other. int a = 1 ^ 3 (This returns 2.)
| The binary OR operator performs a binary operation on the left and right value. This returns the bits set in either. int a = 1 | 3 (This returns 3.)
+ The plus operator adds operands. int a = 1 + 4 (This returns 5.)
- The minus operator subtracts the left or right values. int a = 4 - 1 (This returns 3.)
? The ternary operator takes three values. If value 1 is true, value 2 is returned. Else, value 3 is returned. int a = (x > 3) ? 1:5 (If x is greater than 3, then return 1, else return 5.)

Relational operators are used in X++ to compare the values between variable values of similar types. Some limitations with complex data types such as GUIDs apply.

Operator Description
Like This operator is exclusively used in SQL statements and returns true if the criteria are found within the second value. For example, select a table where a field such as ‘12*’ returns all rows from a table where the field values start with 12.
== Returns true if the values are equal.
!= Returns true if the first value is not equal to the second value.
>= Returns true if the first value is greater than or equal to the second value.
<= Returns true if the first value is less than or equal to the second value.
> Returns true if the first value is greater than the second value.
< Returns true if the first value is less than the second value.
&& Returns true if the first and second value are true.
|| Returns true if the first or second value is true.
! Returns true if the value is false, and it returns false if the value is true.

A ternary operator allows you to evaluate if an expression is true or false to get a result. This is like an if statement, which is discussed in the Use conditional and iterative statements and Exception handling units. However, where an if statement provides conditional branching for the code that is being run, the ternary operator result can be assigned to a variable. The following example checks if the variable x is equal to 5. If it is equal to 5, then the ternary operator assigns the value Yes to the result variable. If x does not equal 5, the ternary operator assigns the value No to the result variable.

result = (x==5) ? "Yes" : "No";