Plans for a new Crystal language server implementation have been brewing for a while, and with the growing interest in Crystal editor and tooling support, I feel that this a great time to share those plans and get more community engagement/feedback/support for it.
The official tree-sitter implementation is still in the works but is already a huge step in the right direction for editor and tooling support. For those that don’t know or need a refresher, tree-sitter is a blazingly fast incremental parsing library that can provide detailed information about the source it’s parsing (which in this case, is Crystal). This already gives us a head-start as the complexities of the language can be accurately expressed in a simple grammar rather than having to re-implement those stages in Crystal. Plus, the added benefit of having first-class support in many editors gives enthusiastic Crystalists the opportunity to take advantage of tree-sitter while it’s still being developed, instead of having to wait for stable releases of other tools.
The main idea for this language server is to leverage the power of tree-sitter to provide general syntactical analysis. From a feature standpoint, that means:
- Incredibly fast symbol generation and lookups
- Retroactive project indexing and analysis
- Goto definition support
- (potential) Basic static analysis
- (potential) Integrated formatting
and a few other useful features. From there we can delve into semantic analysis. As mentioned in the Incremental compilation exploration post, this would likely require projects to be strictly typed simply because of the complexity of type inference in Crystal. The information can then be cached and retroactively updated rather than having to be re-evaluated on every language server event. Feature-wise, that means:
- Context-based goto definition support
- Context hover information
- Method and type completion
and a lot more other features. Not to mention, the possibilities with direct file integrations like with
shard.yml, spec integrations and debugger implementations would now be possible via the language server. There is truly a lot to look forward to!
All these great things mentioned will of course take time to implement, and at present the language server is not even remotely close to being able to handle any of these features — this is something that will take months to complete. There are also things not listed that may or may not be implemented depending on feasibility and complexity, but those can be discussed in this forum. For now, all I can say is that the future of Crystal editor and tooling support is a bright one!