📎 Serialization for AST/CST

[NicholasLYang]

Description

This will be very useful for the playground and for inspecting trees in general.

[MichaReiser]

There's an existing string serialization format but that's hard to inspect. I believe it could help to be more explicit about what the goal is because it may then differ significantly how we approach this.

• Serializing the whole AST can be slow for large files and may, therefore, not be desired
• It may be sufficient to instead expose the metadata for each node kind. Kind of a reflection (readonly) API for SyntaxNodes.
• Have you looked into if we could integrate Rome into astexplorer

[ematipico]

Serializing the whole AST can be slow for large files and may, therefore, not be desired

We could add a feature and expose the serialization method only if that feature is enabled.

[ematipico]

What's the end goal of the feature? Do you have any idea of what you want to try to achieve at the moment?

[Stupremee]

What kind of serialization do you want to achieve? Machine readable for storing them in some data format using serde, or human readable representation?

[ematipico]

My guess is serde. I think what we want to achieve is a way "inspect" the source code from a location and vice-versa. Giving a UI with two windows where in one we have the source code and in the other the AST:

1. by highlighting a section of the source code we should be able to jump to the correct section of the AST;
2. by clicking on AST node, we should be able to highlight the node in the source code;

[Stupremee]

If you're looking for adding serde support to the CST, I basically implemented this already here. It's not the exact same CST, but similar enough. I basically serialize all the events and deserialize a tree by building it up again using GreenNodeBuilder.

If you would use this on a Web UI / Playground, you could read the serialised events in JavaScript and then convert them to something interactive on the page.