Data driven entity generation by YAML definitions

[axyiee]

Entity generation by YAML definitions

Table of contents:

• 📰 Summary
• 🤔 Motivations and the proposed solution
• • 🦀 Rust
• • ☕ Kotlin
• 🌐 Examples
• 🔗 Reference
• 🤷 Final considerations

Summary

We should create two code generators (one written in Kotlin and another written in Rust) which would generate entities based on fields defined in a YAML file.

Motivations and the proposed solution

As mentioned in #21, "we need to create an entity data class in Kotlin with the same contents as Rust for the rest web client, this means that we would have duplicated code". This feature would fix this problem and add more flexibility to entity changes. We could also integrate this into the command-line interface for better management of this solution.

Rust

Implementing this feature in Rust is really simple though, since we can simple use function-like procedural macros¹ that read the YAML files, parse them and generate code.

Kotlin

I still haven't thought of a better way to implement this, but I know we can use Gradle tasks and square/kotlinpoet² for code generation.

Examples

player.yml

---
entities:
  - name: Player
    package: org.hexalite.generation.entity
    fields:
       uuid:
         kotlin: java.util.UUID
         rust: uuid::Uuid
       hexes:
         kotlin: Int
         rust: u32
       created_at:
         kotlin: kotlinx.datetime.Instant
         rust: chrono::DateTime<chrono::Utc>

Reference

1. Procedural macros
2. square/kotlinpoet
3. YAML specification

Final considerations

Suggestions are appreciated for new sections in this issue, or if you have a better idea about how to structure it, feel free to let us know about it by commenting down below. Thank you for the attention.

[axyiee]

We should use ProtoBuf instead. It is a better alternative and it is suited for this exact use case, it would be a really better alternative.

[axyiee]

Closed by 0b0b79e

[axyiee]

We should use ProtoBuf instead. It is a better alternative and it is suited for this exact use case, it would be a really better alternative.

Ok, so this issue need to be reopened. There is no decent ProtoBuf compiler for Kotlin in which adds good compatibility for kotlinx.serialization and possibility to wrap classes (e.g. compatibility to UUIDs by passing an option). This issue will be closed again when we found a compiler for Kotlin, for a while we will reimplement ProtoBuf definitions in Kotlin manually.

[axyiee]

We should use ProtoBuf instead. It is a better alternative and it is suited for this exact use case, it would be a really better alternative.

Ok, so this issue need to be reopened. There is no decent ProtoBuf compiler for Kotlin in which adds good compatibility for kotlinx.serialization and possibility to wrap classes (e.g. compatibility to UUIDs by passing an option). This issue will be closed again when we found a compiler for Kotlin, for a while we will reimplement ProtoBuf definitions in Kotlin manually.

It seems the official grpc-kotlin repository has support for code generation.