feat(lsp): add code actions, signature help, and document highlights

Assisted-by: MiMo V2.5 Pro

lsp/protocol.go

@@ -309,11 +309,75 @@ type ServerCapabilities struct {
 	RenameProvider             bool           `json:"renameProvider,omitempty"`
 	DocumentSymbolProvider     bool           `json:"documentSymbolProvider,omitempty"`
 	DocumentFormattingProvider bool           `json:"documentFormattingProvider,omitempty"`
+	DocumentHighlightProvider  bool           `json:"documentHighlightProvider,omitempty"`
+	CodeActionProvider         bool           `json:"codeActionProvider,omitempty"`
+	SignatureHelpProvider      map[string]any `json:"signatureHelpProvider,omitempty"`
 	SemanticTokensProvider     map[string]any `json:"semanticTokensProvider,omitempty"`
 	InlayHintProvider          bool           `json:"inlayHintProvider,omitempty"`
 	DiagnosticProvider         map[string]any `json:"diagnosticProvider,omitempty"`
 }
 
+// --- code actions -------------------------------------------------------------
+
+type codeActionParams struct {
+	TextDocument textDocumentIdentifier `json:"textDocument"`
+	Range        Range                  `json:"range"`
+	Context      codeActionContext      `json:"context"`
+}
+
+type codeActionContext struct {
+	Diagnostics []Diagnostic `json:"diagnostics"`
+}
+
+// CodeAction represents a quick fix or refactoring.
+type CodeAction struct {
+	Title string         `json:"title"`
+	Kind  string         `json:"kind,omitempty"`
+	Edit  *WorkspaceEdit `json:"edit,omitempty"`
+}
+
+// --- signature help -----------------------------------------------------------
+
+type signatureHelpParams struct {
+	TextDocument textDocumentIdentifier `json:"textDocument"`
+	Position     Position               `json:"position"`
+}
+
+// SignatureHelp represents signature information for a function call.
+type SignatureHelp struct {
+	Signatures []SignatureInformation `json:"signatures"`
+}
+
+// SignatureInformation represents a function signature.
+type SignatureInformation struct {
+	Label         string                 `json:"label"`
+	Documentation string                 `json:"documentation,omitempty"`
+	Parameters    []ParameterInformation `json:"parameters,omitempty"`
+}
+
+// ParameterInformation represents a parameter in a signature.
+type ParameterInformation struct {
+	Label string `json:"label"`
+}
+
+// --- document highlights ------------------------------------------------------
+
+type documentHighlightParams struct {
+	TextDocument textDocumentIdentifier `json:"textDocument"`
+	Position     Position               `json:"position"`
+}
+
+// DocumentHighlight represents a highlight range.
+type DocumentHighlight struct {
+	Range Range `json:"range"`
+	Kind  int   `json:"kind,omitempty"`
+}
+
+const (
+	highlightRead  = 1
+	highlightWrite = 2
+)
+
 type initializeResult struct {
 	Capabilities ServerCapabilities `json:"capabilities"`
 	ServerInfo   map[string]string  `json:"serverInfo,omitempty"`