Add a keyboard shortcut for triggering on-hover docs (#508)

* Add a keyboard shortcut for triggering on-hover docs

* Update changelog

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Introduced file system abstraction and an S3 support ([#492](https://github.com/livebook-dev/livebook/pull/492))
 - Added support for configuring file systems using env variables ([#498](https://github.com/livebook-dev/livebook/pull/498))
+- Added a keyboard shortcut for triggering on-hover docs ([#508](https://github.com/livebook-dev/livebook/pull/508))
 
 ### Fixed
 

assets/js/cell/live_editor.js

@@ -1,4 +1,4 @@
-import monaco from "./live_editor/monaco";
+import monaco, { addKeybinding } from "./live_editor/monaco";
 import EditorClient from "./live_editor/editor_client";
 import MonacoEditorAdapter from "./live_editor/monaco_editor_adapter";
 import HookServerAdapter from "./live_editor/hook_server_adapter";
@@ -193,6 +193,18 @@ class LiveEditor {
       const contentHeight = this.editor.getContentHeight();
       this.container.style.height = `${contentHeight}px`;
     });
+
+    // Replace built-in keybindings
+    // Note that generally we want to stick to defaults, so that we match
+    // VS Code, but some keybindings are overly awkward, in which case we
+    // add our own
+
+    // By default this is a sequence of: Ctrl + K Ctrl + I
+    addKeybinding(
+      this.editor,
+      "editor.action.showHover",
+      monaco.KeyMod.CtrlCmd | monaco.KeyCode.KEY_I
+    );
   }
 
   /**

assets/js/cell/live_editor/monaco.js

@@ -1,4 +1,5 @@
 import * as monaco from "monaco-editor/esm/vs/editor/editor.api";
+import { CommandsRegistry } from "monaco-editor/esm/vs/platform/commands/common/commands";
 import ElixirOnTypeFormattingEditProvider from "./elixir/on_type_formatting_edit_provider";
 import theme from "./theme";
 
@@ -80,3 +81,23 @@ export function highlight(code, language) {
     return result.replace(/<br\/>$/, "");
   });
 }
+
+/**
+ * Updates keybinding for the given editor command.
+ *
+ * This uses an internal API, since there is no clean support
+ * for customizing keybindings.
+ * See https://github.com/microsoft/monaco-editor/issues/102#issuecomment-822981429
+ */
+export function addKeybinding(editor, id, newKeybinding) {
+  const { handler, when } = CommandsRegistry.getCommand(id) ?? {};
+
+  if (handler) {
+    editor._standaloneKeybindingService.addDynamicKeybinding(
+      id,
+      newKeybinding,
+      handler,
+      when
+    );
+  }
+}

lib/livebook_web/live/session_live/shortcuts_component.ex

@@ -11,6 +11,13 @@ defmodule LivebookWeb.SessionLive.ShortcutsComponent do
         desc: "Show completion list, use twice for details",
         basic: true
       },
+      %{
+        seq: ["ctrl", "i"],
+        seq_mac: ["⌘", "i"],
+        press_all: true,
+        desc: "Show identifier documentation",
+        basic: true
+      },
       %{
         seq: ["ctrl", "shift", "i"],
         seq_mac: ["⇧", "⌥", "f"],