Startup Guide for New Users ‐ Draft

Introduction to the Apache Daffodil Extension for Visual Studio Code

The Mission: Make Daffodil Coding & Debugging Easier The Command Line Interface with existing Daffodil debugging capability is non-intuitive and difficult to master

The Solution: Integrate Daffodil with Visual Studio Source Level Debugging Breakpoints Single Stepping Syntax Highlighting Context Aware Code Completion Assistance Data view & Location Tracking Interactive Infoset Viewing

The How: VSCode plug-in extension DAPodil interface server Ω-Edit data editor Apache Daffodil w/ integrated Debugger

The Caveats: No new functionality has been added to Daffodil’s integrated debugger VisualStudio simply provides a simpler, more intuitive user interface Not all debugger capabilities are available via VisualStudio.

The code being executed within Daffodil is a parser that it constructed based upon the provided schema. There is not a one-to-one correspondence between the schema structure and that of the parser. This means that there is not a one-to-one correspondence between the lines in the schema and what Daffodil executes when the user asks the debugger to “step”. There will be instances where the “step” does not result in movement of the indicator showing current location within the schema. This is similar to, but more exaggerated than, debugging code compiled with optimization enabled. Additionally, data shown in the infoset may appear in chunks and/or may be removed when the parser backtracks if a parse branch is found to be incorrect.

Don’t worry if you’re new to IDE use and don’t know what any of this means. We’ll cover it in detail later.

IDE Basics Integrated Development Environment A single program that integrates all the steps of software development Editing Compiling Execution Debugging Version Control

IDE Basics Integrated Development Environment A single program that integrates all the steps of software development Editing Compiling Execution Debugging Version Control

IDE Basics Integrated Development Environment A single program that integrates all the steps of software development Editing Compiling Execution Debugging Version Control

IDE Basics Integrated Development Environment A single program that integrates all the steps of software development Editing Compiling Execution Debugging Version Control

IDE Basics Integrated Development Environment A single program that integrates all the steps of software development Editing Compiling Execution Debugging Version Control

Install Visual Studio Code Free and built on open source Available for Windows, Linux, macOS and web browsers	Click Image for Download Page:

Installing the Daffodil Extension In Visual Studio Code, click on the Extensions Icon.

Installing the Daffodil Extension In Visual Studio Code, click on the Extensions Icon Then enter “daffodil” in the search box

Installing the Daffodil Extension In Visual Studio Code, click on the Extensions Icon. Then enter “daffodil” in the search box Click on the Apache Daffodil tile

Installing the Daffodil Extension In Visual Studio Code, click on the Extensions Icon. Then enter “daffodil” in the search box Click on the Apache Daffodil tile Click on the Install button

Installing the Daffodil Extension In Visual Studio Code, click on the Extensions Icon. Then enter “daffodil” in the search box Click on the Apache Daffodil tile Click on the Install button Upon installation, the Install button will be replaced by Disable & Uninstall buttons

Configuring for First Use Create a working directory Sample data file Sample schema file Free sample schemas here	This example uses a Daffdile logo saved as a PNG file

Configuring for First Use Open the working directory Click File Click Open Folder Navigate to & Select your folder

Note that if you wind up working on multiple DFDL projects in different folders, you will need to configure each folder with it's own launch.json file

Configuring for First Use Configuring Launch.json file Open the Launch Config Wizard Press Ctrl + k Then press p In the search bar that opens, begin entering: "Daffodil" When the list shows Daffdodil Debug: Configure launch.json, select it
The Launch Config Wizard will open in a new tab.

Note that the debugger should run with the default settings. You may simply scroll down to the bottom of the configuration wizard and click the SAVE button, then close the wizard.
If you run into a problem, the most likely problem is that you have not yet opened a working folder/directory. The second most likely culprit is a port conflict and you can simply reopen the configuration wizard and change the port settings and save the new configuration.

Configuring for First Use Launch Config Wizard Launch config: The file can hold multiple configurations. 1. Enter a name for the new configuration    or 2. Select a previous configuration from the drop-down list

Configuring for First Use Launch Config Wizard
Main Schema File/Input Data File The input files can be hard coded into the configuration by clicking the Browse button and navigating to the file and clicking on it

Leave the ${command:AskForSchemaName}/${command:AskForDataName} values and you will be prompted for the file names each time you execute a parse. This oiption can be usefull if you will be testing with a variety of input files, rather than running the same files repeatedly

Configuring for First Use Launch Config Wizard
Root Element For simple schemas, this field may be left set to undefined

Configuring for First Use Launch Config Wizard
Debugger Settings Port - Port used for communication between VSCode & Daffodil Debugger. Log File - Specify name & locaion of the log file. Log Level - specify the level of information to be logged. Use Existing Server - ignore Stop On Entry - Essentially sets a breakpoint on the first line. Trace - logging of internal communications

Configuring for First Use Launch Config Wizard
Classpath Complex schemas often require multiple locations and JAR files. The debugger needs to know where to find these additional files Infoset Infoset Format - Select XML or JSON for the ouput Output Type - store output to a file or stream to console Output Infoset Path - specify the location for the output file