feat(lsp): add textDocument/inlineCompletion support

book/src/generated/static-cmd.md

@@ -213,6 +213,11 @@
 | `keep_primary_selection` | Keep primary selection | normal: `` , ``, select: `` , `` |
 | `remove_primary_selection` | Remove primary selection | normal: `` <A-,> ``, select: `` <A-,> `` |
 | `completion` | Invoke completion popup | insert: `` <C-x> `` |
+| `inline_completion_accept` | Accept inline completion |  |
+| `inline_completion_dismiss` | Dismiss inline completion |  |
+| `inline_completion_next` | Cycle to next inline completion |  |
+| `inline_completion_prev` | Cycle to previous inline completion |  |
+| `inline_completion_trigger` | Trigger inline completion |  |
 | `hover` | Show docs for item under cursor | normal: `` <space>k ``, select: `` <space>k `` |
 | `toggle_comments` | Comment/uncomment selections | normal: `` <C-c> ``, `` <space>c ``, select: `` <C-c> ``, `` <space>c `` |
 | `toggle_line_comments` | Line comment/uncomment selections | normal: `` <space><A-c> ``, select: `` <space><A-c> `` |

helix-core/src/syntax/config.rs

@@ -274,6 +274,7 @@ pub enum LanguageServerFeature {
     RenameSymbol,
     InlayHints,
     DocumentColors,
+    InlineCompletion,
 }
 
 impl Display for LanguageServerFeature {
@@ -299,6 +300,7 @@ impl Display for LanguageServerFeature {
             RenameSymbol => "rename-symbol",
             InlayHints => "inlay-hints",
             DocumentColors => "document-colors",
+            InlineCompletion => "inline-completion",
         };
         write!(f, "{feature}",)
     }

helix-lsp-types/src/inline_completion.rs

@@ -55,7 +55,7 @@ pub struct InlineCompletionParams {
     pub context: InlineCompletionContext,
 }
 
-/// Describes how an [`InlineCompletionItemProvider`] was triggered.
+/// Describes how an `InlineCompletionItemProvider` was triggered.
 ///
 /// @since 3.18.0
 #[derive(Eq, PartialEq, Clone, Copy, Deserialize, Serialize)]
@@ -137,7 +137,7 @@ pub struct InlineCompletionItem {
     /// Is used both for the preview and the accept operation.
     pub insert_text: String,
     /// A text that is used to decide if this inline completion should be
-    /// shown. When `falsy` the [`InlineCompletionItem::insertText`] is
+    /// shown. When `falsy` the [`InlineCompletionItem::insert_text`] is
     /// used.
     ///
     /// An inline completion is shown if the text to replace is a prefix of the

helix-lsp-types/src/lib.rs

@@ -153,9 +153,7 @@ pub use inlay_hint::*;
 mod inline_value;
 pub use inline_value::*;
 
-#[cfg(feature = "proposed")]
 mod inline_completion;
-#[cfg(feature = "proposed")]
 pub use inline_completion::*;
 
 mod moniker;
@@ -1596,7 +1594,6 @@ pub struct TextDocumentClientCapabilities {
     ///
     /// @since 3.18.0
     #[serde(skip_serializing_if = "Option::is_none")]
-    #[cfg(feature = "proposed")]
     pub inline_completion: Option<InlineCompletionClientCapabilities>,
 }
 
@@ -2060,7 +2057,6 @@ pub struct ServerCapabilities {
     ///
     /// @since 3.18.0
     #[serde(skip_serializing_if = "Option::is_none")]
-    #[cfg(feature = "proposed")]
     pub inline_completion_provider: Option<OneOf<bool, InlineCompletionOptions>>,
 
     /// Experimental server capabilities.

helix-lsp-types/src/request.rs

@@ -661,10 +661,8 @@ impl Request for PrepareRenameRequest {
 }
 
 #[derive(Debug)]
-#[cfg(feature = "proposed")]
 pub enum InlineCompletionRequest {}
 
-#[cfg(feature = "proposed")]
 impl Request for InlineCompletionRequest {
     type Params = InlineCompletionParams;
     type Result = Option<InlineCompletionResponse>;

helix-lsp/src/client.rs

@@ -389,6 +389,10 @@ impl Client {
                         | ColorProviderCapability::Options(_)
                 )
             ),
+            LanguageServerFeature::InlineCompletion => matches!(
+                capabilities.inline_completion_provider,
+                Some(OneOf::Left(true) | OneOf::Right(_))
+            ),
         }
     }
 
@@ -701,6 +705,9 @@ impl Client {
                         dynamic_registration: Some(false),
                         resolve_support: None,
                     }),
+                    inline_completion: Some(lsp::InlineCompletionClientCapabilities {
+                        dynamic_registration: Some(false),
+                    }),
                     ..Default::default()
                 }),
                 window: Some(lsp::WindowClientCapabilities {
@@ -1135,6 +1142,29 @@ impl Client {
         Some(self.call::<lsp::request::InlayHintRequest>(params))
     }
 
+    pub fn inline_completion(
+        &self,
+        text_document: lsp::TextDocumentIdentifier,
+        position: lsp::Position,
+        context: lsp::InlineCompletionContext,
+        work_done_token: Option<lsp::ProgressToken>,
+    ) -> Option<impl Future<Output = Result<Option<lsp::InlineCompletionResponse>>>> {
+        if !self.supports_feature(LanguageServerFeature::InlineCompletion) {
+            return None;
+        }
+
+        let params = lsp::InlineCompletionParams {
+            text_document_position: lsp::TextDocumentPositionParams {
+                text_document,
+                position,
+            },
+            context,
+            work_done_progress_params: lsp::WorkDoneProgressParams { work_done_token },
+        };
+
+        Some(self.call::<lsp::request::InlineCompletionRequest>(params))
+    }
+
     pub fn text_document_document_color(
         &self,
         text_document: lsp::TextDocumentIdentifier,

helix-term/src/commands.rs

@@ -516,6 +516,11 @@ impl MappableCommand {
         keep_primary_selection, "Keep primary selection",
         remove_primary_selection, "Remove primary selection",
         completion, "Invoke completion popup",
+        inline_completion_accept, "Accept inline completion",
+        inline_completion_dismiss, "Dismiss inline completion",
+        inline_completion_next, "Cycle to next inline completion",
+        inline_completion_prev, "Cycle to previous inline completion",
+        inline_completion_trigger, "Trigger inline completion",
         hover, "Show docs for item under cursor",
         toggle_comments, "Comment/uncomment selections",
         toggle_line_comments, "Line comment/uncomment selections",
@@ -5262,6 +5267,54 @@ pub fn completion(cx: &mut Context) {
         .trigger_completions(cursor, doc.id(), view.id);
 }
 
+pub fn inline_completion_accept(cx: &mut Context) {
+    let (view, doc) = current!(cx.editor);
+    if let Some(c) = doc.inline_completions.take_and_clear() {
+        let text = doc.text();
+        let cursor = doc.selection(view.id).primary().cursor(text.slice(..));
+        let new_cursor = cursor + c.ghost_text.chars().count();
+        let t = Transaction::change(
+            text,
+            std::iter::once((cursor, c.replace_range.to(), Some(c.ghost_text.into()))),
+        )
+        .with_selection(Selection::point(new_cursor));
+        doc.apply(&t, view.id);
+    }
+}
+
+pub fn inline_completion_dismiss(cx: &mut Context) {
+    if doc_mut!(cx.editor)
+        .inline_completions
+        .take_and_clear()
+        .is_none()
+    {
+        normal_mode(cx);
+    }
+}
+
+pub fn inline_completion_next(cx: &mut Context) {
+    use helix_core::movement::Direction;
+    let doc = doc_mut!(cx.editor);
+    doc.inline_completions.cycle(Direction::Forward);
+    doc.inline_completions
+        .rebuild_overlays(&mut doc.inline_completion_overlays);
+}
+
+pub fn inline_completion_prev(cx: &mut Context) {
+    use helix_core::movement::Direction;
+    let doc = doc_mut!(cx.editor);
+    doc.inline_completions.cycle(Direction::Backward);
+    doc.inline_completions
+        .rebuild_overlays(&mut doc.inline_completion_overlays);
+}
+
+pub fn inline_completion_trigger(_cx: &mut Context) {
+    use helix_lsp::lsp;
+    crate::handlers::inline_completion::trigger_inline_completion(
+        lsp::InlineCompletionTriggerKind::Invoked,
+    );
+}
+
 // comments
 type CommentTransactionFn = fn(
     line_token: Option<&str>,

helix-term/src/handlers.rs

@@ -13,25 +13,28 @@ use crate::handlers::signature_help::SignatureHelpHandler;
 pub use helix_view::handlers::{word_index, Handlers};
 
 use self::document_colors::DocumentColorsHandler;
+use self::inline_completion::InlineCompletionHandler;
 
 mod auto_save;
 pub mod completion;
 pub mod diagnostics;
 mod document_colors;
+pub mod inline_completion;
 mod prompt;
 mod signature_help;
 mod snippet;
 
 pub fn setup(config: Arc<ArcSwap<Config>>) -> Handlers {
     events::register();
 
-    let event_tx = completion::CompletionHandler::new(config).spawn();
+    let event_tx = completion::CompletionHandler::new(config.clone()).spawn();
     let signature_hints = SignatureHelpHandler::new().spawn();
     let auto_save = AutoSaveHandler::new().spawn();
     let document_colors = DocumentColorsHandler::default().spawn();
     let word_index = word_index::Handler::spawn();
     let pull_diagnostics = PullDiagnosticsHandler::default().spawn();
     let pull_all_documents_diagnostics = PullAllDocumentsDiagnosticHandler::default().spawn();
+    let inline_completions = InlineCompletionHandler::new(config.clone()).spawn();
 
     let handlers = Handlers {
         completions: helix_view::handlers::completion::CompletionHandler::new(event_tx),
@@ -41,6 +44,7 @@ pub fn setup(config: Arc<ArcSwap<Config>>) -> Handlers {
         word_index,
         pull_diagnostics,
         pull_all_documents_diagnostics,
+        inline_completions,
     };
 
     helix_view::handlers::register_hooks(&handlers);
@@ -50,6 +54,7 @@ pub fn setup(config: Arc<ArcSwap<Config>>) -> Handlers {
     diagnostics::register_hooks(&handlers);
     snippet::register_hooks(&handlers);
     document_colors::register_hooks(&handlers);
+    inline_completion::register_hooks(&handlers);
     prompt::register_hooks(&handlers);
     handlers
 }