Final Report

Intro:

Hi everyone, it’s the end of GSoc! I had a great experience throughout this whole process. I’ve learned so much. This is essentially the ‘final report’ for GSoC, but not my final report for this project in general by a long shot. I still have so much more I want to do, but here is what I’ve done so far.

Project:

JSON, YAML, and/or XML emitting and parsing integration into Vala’s compiler.

Mentor:

I would like to thank Lorenz Wildberg for being my mentor for this project, as well as the Vala community.

Description:

The main objective of this project is to integrate direct syntax support for parsing and emitting JSON, XML, and/or YAML formats in Vala. This will cut back the boilerplate code, making it more user-friendly and efficient for developers working with these formatting languages.

What I’ve done:

Research

• I’ve done significant research in both JSON and YAML parsing and emitting in various languages like C#, Java, Rust and Python.
• Looked into how Vala currently handles JSON using JSON GLib classes, and I then modelled the C code after the examples I collected.
• Modelled the JSON module after other modules in the codegen, specifically, mainly after Dbus, Gvariant, GObject, and GTK.

Custom JSON Overrides and Attribute

• Created Vala syntax sugar specifically making a [JSON] attribute to do serialization.
• Built support for custom overrides as in mapping JSON keys to differently named fields/properties.
• Reduced boilerplate by generating C code behind the scenes.

Structs

• I’ve created both Vala functions to deserialize and serialize structs using JSON boxed functions.
• I created a Vala generate_struct_serialize_func function to create a C code function called _%s_serialize_func to serialize fields.

• I then created a Vala function generate_struct_to_json to create a C code function called _json_%s_serialize_mystruct to fully serialize the struct by using boxed serialize functions.
  

• I created a Vala generate_struct_deserialize_func function to create a C code function called _%s_deserialize_func to deserialize fields.
• I then created a Vala function generate_struct_to_json to create a C code function called _json_%s_deserialize_mystruct to fully deserialize the struct by using boxed deserialized functions.

GObjects

• I’ve created both Vala functions to deserialize and serialize GObjects using json_gobject_serialize and JSON generator.

• I then created a Vala function generate_gclass_to_json to create a C code function called _json_%s_serialize_gobject_myclass to fully serialize GObjects.
  

• I created a Vala generate_gclass_from_json function to create a C code function called _json_%s_deserialize_class to deserialize fields.

Non-GObjects

• I’ve done serializing of non-GObjects using JSON GLib’s builder functions.
• I then created a Vala function generate_class_to_json to create a C code function called _json_%s_serialize_myclass to fully serialize non-objects that aren’t inheriting from Object or Json.Serializable.

Future Work:

Research

• Research still needs to be put into integrating XML and determining which library to use.
• The integration of YAML and other formatting languages not only JSON, YAML, or XML.

Custom Overrides and Attributes

• I want to create more specialized attributes for JSON that only do serialization or deserialization. Such as [JsonDeserialize] and [JsonSerialize] or something similar.
• [JSON] attribute needs to do both deserializing and serializing, and at the moment, the deserializing code has problems.
• XML, YAML, and other formating languages will follow very similar attribute patterns: [Yaml], [Xml], [Json].

Bugs

• unref c code functions are calling nulls, which shouldn’t be the cause. They need proper types going through.
• Deserializing prompts a redefinition that needs to be corrected.
• Overridden GObject properties need to have setters made to be able to get the values.

Links

• Here is the JSON module that has majority of the code.
• Here is the merge request.