Introduction to X++ (Detailed X++ Language Reference)

 

Introduction to X++

X++ is a high-level programming language designed for enterprise resource planning (ERP) systems and database applications. It combines object-oriented, application-aware, and data-aware paradigms to facilitate complex business process management and data manipulation.

Key Features of X++

1. Classes:

   • System Classes: Provide core functionalities, such as file handling, collections, and data manipulation.
   • Application Classes: Manage various business processes specific to ERP systems.
   • Reflection: Allows introspection of classes to dynamically access properties and methods at runtime.

2. Tables:

   • Access to Relational Tables: X++ allows direct interaction with database tables using syntax similar to SQL.
   • Keywords: Includes keywords for data definition and manipulation, akin to SQL.
   • Reflection: Supports introspection on tables for dynamic access to fields and methods.

3. User Interface:

   • Forms and Reports: X++ provides the ability to create and manipulate UI elements such as forms and reports, enabling a rich user interface for business applications.

4. Best Practice Checks:

   • Syntax Checking: Ensures code is free of syntax errors during compilation.
   • Best Practice Violations: Detects and reports deviations from coding best practices, helping maintain code quality and consistency.

5. Garbage Collection:

   • Automatic Memory Management: The runtime environment automatically discards objects that are no longer referenced, freeing up memory for other operations.

6. Interoperability:

   • .NET Languages: X++ supports interoperability with other .NET languages like C#, enabling seamless integration of components and logic across languages.
   • Assemblies: X++ applications can reference and utilize classes from other .NET assembly DLL files.

7. File Manipulation:

   • File I/O: Supports file input and output operations.
   • XML Handling: Includes functionalities for building and parsing XML documents.

8. Collections:

   • Dynamic Arrays: Provides support for dynamic arrays.
   • Collection Objects: Includes various collection objects like lists, maps, and sets for managing groups of data.

Compilation to .NET CIL

X++ source code is compiled to Microsoft .NET Common Intermediate Language (CIL), similar to other .NET languages like C# and Visual Basic. This offers several advantages:

• Performance: Compiled X++ code runs significantly faster than interpreted code in earlier versions (e.g., AX2012).
• Integration: Simplifies the integration of application logic written in other managed languages.
• Efficiency: Enables efficient referencing of classes in other .NET assembly DLL files.
• Tool Compatibility: CIL can be utilized with various .NET development tools.
• Consistent Compilation: If any method in a model element (e.g., class, form, query) fails to compile, the entire compilation fails, ensuring consistency.

For those upgrading from AX2012 or earlier, note that CIL helper methods like Global::runClassMethodIL have been removed.

Ignore List for Legacy Code

When porting legacy applications, it may be necessary to test parts of the application before everything is fully ported. To facilitate this, you can ignore parts of your X++ code by specifying methods in an XML document. This feature should only be used during development and testing, not in production.

To add exclusions:

1. Right-click on the project.
2. Select "Edit Best Practice Suppressions."
3. Edit the XML document that appears.

X++ Programming Concepts

The X++ language programming reference is divided into the following sections:

1. Variables and Data Types:

   • Variables: Declare variables using types like int, str, real, date, and enum.
   • Data Types: Supported data types include primitive types (e.g., integers, strings) and complex types (e.g., containers, objects).

2. Statements, Loops, and Exception Handling:

   • Control Flow Statements: Use if, else, switch, and case for conditional logic.
   • Loops: Implement loops using while, do-while, and for statements.
   • Exception Handling: Handle errors with try, catch, and throw statements.

3. Operators:

   • Arithmetic Operators: +, -, *, /, %.
   • Comparison Operators: ==, !=, <, >, <=, >=.
   • Logical Operators: &&, ||, !.
   • Bitwise Operators: &, |, ^, ~, <<, >>.

4. Classes and Methods:

   • Defining Classes: Create classes using the class keyword, with support for inheritance and polymorphism.
   • Methods: Define methods within classes to encapsulate behavior.
   • Access Modifiers: Use public, private, protected to control access to class members.

5. Data Selection and Manipulation:

   • Queries: Use select statements to retrieve data from tables.
   • Inserts, Updates, Deletes: Perform data manipulation operations on tables.
   • Joins and Aggregates: Support for complex queries with joins and aggregate functions.

6. Macros:

   • Macro Definitions: Use #define and #macro to create reusable code snippets.
   • Preprocessor Directives: Include and conditionally compile code using preprocessor directives.

7. Attribute Classes:

   • Metadata: Define metadata for classes, methods, and fields using attribute classes.
   • Custom Attributes: Create and use custom attribute classes to add additional metadata.