Index declarations as symbols for LSP symbol search (#87)

Index procedure declarations as "symbols" in the language server, making
them available for document and project-wide symbol searches.

Among other things this involved a bit of cleanup in the initialization
code path, and exposing the `textDocument/documentSymbol` and
`workspace/symbol` capabilities.

To facilitate project-wide symbol search by a user, we add a cache and
populate it with symbols from _all_ Technique files in the local
project. The **ignore** crate is used so that files ignored by e.g.
_.gitignore_ are omitted when searching.

Procedure declarations are sent as `SymbolKind::CONSTRUCTOR`, matching
the context used in syntax highlighting.

Author: istathar

Cargo.lock

@@ -9,6 +9,7 @@ license = "MIT"
 
 [dependencies]
 clap = { version = "4.5.16", features = [ "wrap_help" ] }
+ignore = "0.4"
 lsp-server = "0.7.9"
 lsp-types = "0.97"
 owo-colors = "4"

Cargo.toml

@@ -14,17 +14,19 @@ pub(crate) fn run_language_server() {
     let capabilities = serde_json::to_value(ServerCapabilities {
         text_document_sync: Some(TextDocumentSyncCapability::Kind(TextDocumentSyncKind::FULL)),
         document_formatting_provider: Some(OneOf::Left(true)),
+        document_symbol_provider: Some(OneOf::Left(true)),
+        workspace_symbol_provider: Some(OneOf::Left(true)),
         ..Default::default()
     })
     .unwrap();
 
     // extract any initialization parameters passed from the editor.
     if let Ok(params) = connection.initialize(capabilities) {
-        let _params = serde_json::from_value::<InitializeParams>(params).unwrap();
+        let params = serde_json::from_value::<InitializeParams>(params).unwrap();
 
         info!("Technique Language Server starting on stdin");
 
-        let server = server::TechniqueLanguageServer::new();
+        let server = server::TechniqueLanguageServer::new(params);
 
         if let Err(e) = server.run(connection) {
             eprintln!("Server error: {}", e);