replace Goscale implementation with Gossamer

[StoyanDrumev]

The current implementation does not support Go reflection, and type definitions are wrapped around Go primitive types, which makes development unpleasant. We propose spending some time trying to integrate Gossamer’s SCALE package since TinyGo has released a new version that includes better reflection support. Narrowing down the missing parts would be beneficial. A single implementation in Go will be more reliable and developer-friendly when it is maintained by both projects, and it will showcase the usage needs of both host and runtime environment.

[radkomih]

It's not possible to switch to the Gossamer scale codec, as the reflect implementation in Tinygo still lacks certain methods that are required by the codec: CanConvert, MethodByName, Call, Out.

[radkomih]

Instead of completely switching to Gossamer's SCALE types, we might consider an alternative approach.
The implementation of their VaryingData type is problematic due to the missing reflect functionality, and it seems unnecessarily complicated. However, the rest of the SCALE types appear to be ok, so we might consider adopting Gossamer's SCALE while using our implementation for the VaryingData type (type VaryingData []Encodable).

Summary of the tests we conducted (using a fork of Gossamer's SCALE implementation with the necessary modifications to support our VaryingData type - https://github.com/LimeChain/gossamer/tree/scale-codec-fixes):

• The encoding works with all basic and composite types (including our wrapper types).
• The implementation of the decoding interface values, which is not supported by Gossamer's SCALE, but is required for our VaryingData type, has an issue, specifically in Tinygo: reflect: setting an interface value tinygo-org/tinygo#4040.

Switching to Gossamer's SCALE seems feasible, however, we will still need to maintain a fork of it with the necessary changes for supporting our VaryingData type. Additionally, this approach could allow for simplification of many parts of the code.

Related issue: #308

[EclesioMeloJunior]

Hello @radkomih! I was working on this project https://github.com/crypto2lab/scale-codec, it is a scale-codec implementation free of reflection and can be compiled to wasm. It already supports enums (VDT's), results, options, tuples and I am still working on structs.

Basically you can have examples of usage here:

• https://github.com/crypto2lab/scale-codec/blob/main/option_test.go
• https://github.com/crypto2lab/scale-codec/blob/main/result_test.go
• https://github.com/crypto2lab/scale-codec/tree/main/tests/enums
  • For enums I created a codegen approach where you write a .scale file and use the tool enum_script simple_enum.scale main (more info in the https://github.com/crypto2lab/scale-codec/blob/main/README.md) and it will output a .go file with all the definitions

[radkomih]

@EclesioMeloJunior thanks a lot for sharing this, I'll definitely check it.