[Q] How to build a tree_sitter::Tree from a sexp representation?

[gagbo]

Hello,

I'd like to be able to somehow save and persist old parsed trees to reuse them in Parser::parse across my application restarts.

Since the Tree structure is a pointer to an FFI struct, I think it's impossible to use a serializer to save the binary data representing the tree to disk in order to retrieve it later.

My next idea is then to save the tree.root_node().to_sexp() (sorry I don't remember the API well) to disk, and then later read this to rebuild a tree directly out of it when needed. Is there a function that would allow doing exactly that? I was imagining something like fn try_from_sexp<'source>(sexp: &str, source: &'source str) -> Result<Tree, _> signature, that wouldn't reparse everything but just "restore" a parsed tree. Might even be an unsafe function, with the safety invariant being that the user of the function should manually ensure that the source still matches the sexp

Thanks for the lib!

[ahlinc]

Tree-sitter doesn't support such case.

1. Tree-sitter's trees are much complex internally and the S-Expression representation shows just a part.
2. If it would be possible to serialize the tree it would take much more space on the disk that original text.

So for the first parse it's better to store an original text and may be in a compressed form.

[gagbo]

I see, that makes sense I guess.

FTR I was thinking of serializing a struct like the data showed by the TreeSitter playground from neovim (so node type and the byte ranges basically). And even if it ends up pretty big, I thought that reading and restoring trees from this information would be better than re-parsing a big .org file.

Thanks for the answer :)