misc: add registers view

assets/dance-white.svg

@@ -0,0 +1 @@
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package.build.ts

@@ -666,6 +666,28 @@ export const pkg = (modules: Builder.ParsedModule[]) => ({
       },
     },
 
+    // Views.
+    // ========================================================================
+
+    viewsContainers: {
+      activitybar: [
+        {
+          id: "dance",
+          title: "Dance",
+          icon: "assets/dance-white.svg",
+        },
+      ],
+    },
+
+    views: {
+      dance: [
+        {
+          id: "registers",
+          name: "Registers",
+        },
+      ],
+    },
+
     // Commands.
     // ========================================================================
 

package.json

@@ -867,6 +867,23 @@
         }
       }
     },
+    "viewsContainers": {
+      "activitybar": [
+        {
+          "id": "dance",
+          "title": "Dance",
+          "icon": "assets/dance-white.svg"
+        }
+      ]
+    },
+    "views": {
+      "dance": [
+        {
+          "id": "registers",
+          "name": "Registers"
+        }
+      ]
+    },
     "commands": [
       {
         "command": "dance.dev.copyLastErrorMessage",

src/state/extension.ts

@@ -11,6 +11,7 @@ import { extensionName } from "../utils/constants";
 import { AutoDisposable } from "../utils/disposables";
 import { assert, CancellationError } from "../utils/errors";
 import { SettingsValidator } from "../utils/settings-validator";
+import { RegistersView } from "./registers-view";
 
 // ===============================================================================================
 // ==  EXTENSION  ================================================================================
@@ -167,6 +168,9 @@ export class Extension implements vscode.Disposable {
     for (const descriptor of Object.values(commands)) {
       this._subscriptions.push(descriptor.register(this));
     }
+
+    // Render views.
+    this._subscriptions.push(new RegistersView(this.registers).register());
   }
 
   /**

src/state/registers-view.ts

@@ -0,0 +1,244 @@
+import * as vscode from "vscode";
+import { Register, Registers, RegisterSet } from "./registers";
+
+/**
+ * A {@link vscode.TreeDataProvider} for Dance registers.
+ */
+export class RegistersView implements vscode.TreeDataProvider<TreeItem> {
+  private readonly _onDidChangeTreeData = new vscode.EventEmitter<TreeItem | undefined>();
+
+  private readonly _registerToItemMap = new Map<Register, RegisterTreeItem>();
+  private readonly _documentToItemMap = new Map<vscode.TextDocument, RegisterSetTreeItem>();
+  private _globalDocumentItem?: RegisterSetTreeItem;
+
+  public readonly onDidChangeTreeData = this._onDidChangeTreeData.event;
+
+  public get isActive() {
+    return this._globalDocumentItem !== undefined;
+  }
+
+  public constructor(
+    public readonly registers: Registers,
+  ) {}
+
+  public getTreeItem(element: TreeItem) {
+    return element;
+  }
+
+  public async getChildren(element?: TreeItem): Promise<vscode.TreeItem[]> {
+    if (element === undefined) {
+      if (this._globalDocumentItem === undefined) {
+        this._globalDocumentItem = new RegisterSetTreeItem(
+          this.registers,
+          () => this._onDidChangeTreeData.fire(this._globalDocumentItem),
+        );
+      }
+
+      const document = vscode.window.activeTextEditor?.document;
+
+      return document === undefined
+        ? [this._globalDocumentItem]
+        : [this._globalDocumentItem, this._itemForDocument(document)];
+    }
+
+    if (element instanceof ValueTreeItem) {
+      return [];
+    }
+
+    if (element instanceof RegisterTreeItem) {
+      return await element.values();
+    }
+
+    let registers = [...element.registers.registers]
+      .filter((r) => r.iconName !== undefined && r.canRead());
+
+    if (element !== this._globalDocumentItem) {
+      registers = registers.filter((r) => /^[a-zA-Z]|.{2,}$/.test(r.name));
+    }
+
+    const items = registers
+      .sort((a, b) => a.name.localeCompare(b.name))
+      .map((r) => this._itemForRegister(r as Register & Register.Readable, element));
+    const shouldShowItem = await Promise.all(items.map(async (item) => await item.shouldShow()));
+
+    return items.filter((_, i) => shouldShowItem[i]);
+  }
+
+  private _itemForDocument(document: vscode.TextDocument) {
+    const existing = this._documentToItemMap.get(document);
+
+    if (existing !== undefined) {
+      return existing;
+    }
+
+    const item: RegisterSetTreeItem = new RegisterSetTreeItem(
+      this.registers.forDocument(document),
+      () => this._onDidChangeTreeData.fire(item),
+      document,
+    );
+
+    this._documentToItemMap.set(document, item);
+
+    return item;
+  }
+
+  private _itemForRegister(register: Register & Register.Readable, documentItem: RegisterSetTreeItem) {
+    const existing = this._registerToItemMap.get(register);
+
+    if (existing !== undefined) {
+      return existing;
+    }
+
+    const item: RegisterTreeItem = new RegisterTreeItem(
+      register,
+      async (wasShown) => {
+        this._onDidChangeTreeData.fire(item);
+
+        if (await item.shouldShow() !== wasShown) {
+          this._onDidChangeTreeData.fire(documentItem);
+        }
+      },
+    );
+
+    this._registerToItemMap.set(register, item);
+
+    return item;
+  }
+
+  public register(): vscode.Disposable {
+    const treeDataProviderDisposable = vscode.window.createTreeView("registers", {
+            treeDataProvider: this,
+            showCollapseAll: true,
+          }),
+          editorChangeDisposable = vscode.window.onDidChangeActiveTextEditor(() =>
+            this.isActive && this._onDidChangeTreeData.fire(undefined),
+          ),
+          documentChangeDisposable = vscode.workspace.onDidCloseTextDocument((e) => {
+            if (!this.isActive) {
+              return;
+            }
+
+            this._documentToItemMap.get(e)?.dispose();
+            this._documentToItemMap.delete(e);
+
+            for (const register of this.registers.forDocument(e).registers) {
+              this._registerToItemMap.get(register)?.dispose();
+              this._registerToItemMap.delete(register);
+            }
+          });
+
+    return {
+      dispose: () => {
+        for (const item of this._documentToItemMap.values()) {
+          item.dispose()
+        }
+
+        for (const item of this._registerToItemMap.values()) {
+          item.dispose();
+        }
+
+        this._globalDocumentItem?.dispose();
+        this._documentToItemMap.clear();
+        this._registerToItemMap.clear();
+
+        treeDataProviderDisposable.dispose();
+        editorChangeDisposable.dispose();
+        documentChangeDisposable.dispose();
+      },
+    };
+  }
+}
+
+class RegisterSetTreeItem extends vscode.TreeItem implements vscode.Disposable {
+  private readonly _disposable: vscode.Disposable;
+
+  public constructor(
+    public readonly registers: RegisterSet,
+    notifyChange: () => void,
+    document?: vscode.TextDocument,
+  ) {
+    super(
+      document?.fileName ?? "Global",
+      vscode.TreeItemCollapsibleState.Expanded,
+    );
+
+    this.iconPath = new vscode.ThemeIcon(document === undefined ? "root-folder" : "folder-active");
+
+    this._disposable = registers.onRegisterChange(() => notifyChange());
+  }
+
+  public dispose() {
+    this._disposable.dispose();
+  }
+}
+
+class RegisterTreeItem extends vscode.TreeItem implements vscode.Disposable {
+  private readonly _disposable: vscode.Disposable;
+
+  private _shouldShow?: Thenable<boolean>;
+  private _values?: Thenable<ValueTreeItem[]>;
+
+  public constructor(
+    public readonly register: Register & Register.Readable,
+    notifyChange: (wasVisible: boolean) => void,
+  ) {
+    super(
+      register.name,
+      /^(["/@^|.]|[a-zA-Z0-9]+)$/.test(register.name)
+        ? vscode.TreeItemCollapsibleState.Expanded
+        : vscode.TreeItemCollapsibleState.Collapsed,
+    );
+
+    if (register.iconName !== undefined) {
+      this.iconPath = new vscode.ThemeIcon(register.iconName);
+    }
+
+    this._disposable = register.onChange(async () => {
+      const wasVisible = await this.shouldShow();
+
+      this._shouldShow = undefined;
+      this._values = undefined;
+
+      notifyChange(wasVisible);
+    });
+  }
+
+  private _shouldShowEmpty() {
+    return /^["/@^|.]$/.test(this.register.name);
+  }
+
+  public async shouldShow() {
+    if (this._shouldShowEmpty()) {
+      return true;
+    }
+
+    if (this._shouldShow === undefined) {
+      this._shouldShow = this.values().then((values) => values.length > 0);
+    }
+
+    return await this._shouldShow;
+  }
+
+  public async values() {
+    if (this._values === undefined) {
+      this._values = this.register.get()
+        .then((values) => values?.map((v) => new ValueTreeItem(v)) ?? []);
+    }
+
+    return await this._values;
+  }
+
+  public dispose() {
+    this._disposable.dispose();
+  }
+}
+
+class ValueTreeItem extends vscode.TreeItem {
+  public constructor(label: string) {
+    super(label, vscode.TreeItemCollapsibleState.None);
+
+    this.iconPath = new vscode.ThemeIcon("symbol-string");
+  }
+}
+
+type TreeItem = RegisterSetTreeItem | RegisterTreeItem | ValueTreeItem;

src/state/registers.ts

@@ -10,16 +10,34 @@ import type * as TrackedSelection from "../utils/tracked-selection";
  * The base class for all registers.
  */
 export abstract class Register {
+  private readonly _onChangeEvent = new vscode.EventEmitter<Register.ChangeKind>();
+
   /**
    * The name of the register.
    */
   public readonly abstract name: string;
 
+  /**
+   * The name of the icon of the register, as seen in the [VS Code product icon
+   * reference](https://code.visualstudio.com/api/references/icons-in-labels#icon-listing).
+   *
+   * `undefined` if the register shouldn't be displayed.
+   */
+  public readonly abstract iconName: string | undefined;
+
   /**
    * The flags of the register, which define what a register can do.
    */
   public readonly abstract flags: Register.Flags;
 
+  /**
+   * Event fired when the contents, selections or recording of the register
+   * change.
+   */
+  public get onChange() {
+    return this._onChangeEvent.event;
+  }
+
   /**
    * Returns whether the register is readable.
    */
@@ -146,6 +164,13 @@ export abstract class Register {
 
     return this as any;
   }
+
+  /**
+   * Notifies listeners that a {@link onChange change} occured to the register.
+   */
+  protected notifyChange(kind: Register.ChangeKind) {
+    this._onChangeEvent.fire(kind);
+  }
 }
 
 export declare namespace Register {
@@ -210,6 +235,12 @@ export declare namespace Register {
     getRecording(): Recording | undefined;
     setRecording(recording: Recording): void;
   }
+
+  export const enum ChangeKind {
+    Contents,
+    Selections,
+    Recording,
+  }
 }
 
 /**
@@ -232,12 +263,14 @@ class GeneralPurposeRegister extends Register implements Register.Readable,
 
   public constructor(
     public readonly name: string,
+    public readonly iconName: string,
   ) {
     super();
   }
 
   public set(values: readonly string[]) {
     this._values = values;
+    this.notifyChange(Register.ChangeKind.Contents);
 
     return Promise.resolve();
   }
@@ -258,6 +291,7 @@ class GeneralPurposeRegister extends Register implements Register.Readable,
     const previousSelectionSet = this._selections;
 
     this._selections = trackedSelections;
+    this.notifyChange(Register.ChangeKind.Selections);
 
     return previousSelectionSet;
   }
@@ -268,6 +302,7 @@ class GeneralPurposeRegister extends Register implements Register.Readable,
 
   public setRecording(recording: Recording) {
     this._recording = recording;
+    this.notifyChange(Register.ChangeKind.Recording);
   }
 }
 
@@ -280,10 +315,20 @@ class SpecialRegister extends Register implements Register.Readable,
     ? Register.Flags.CanRead
     : Register.Flags.CanRead | Register.Flags.CanWrite;
 
+  public override get onChange(): vscode.Event<Register.ChangeKind> {
+    if (this._listenToChanges === undefined) {
+      return super.onChange;
+    }
+
+    return (listener) => this._listenToChanges!(() => listener(Register.ChangeKind.Contents));
+  }
+
   public constructor(
     public readonly name: string,
+    public readonly iconName: string | undefined,
     public readonly getter: () => Thenable<readonly string[]>,
     public readonly setter?: (values: readonly string[]) => Thenable<void>,
+    private readonly _listenToChanges?: (fire: () => void) => vscode.Disposable,
   ) {
     super();
   }
@@ -292,12 +337,14 @@ class SpecialRegister extends Register implements Register.Readable,
     return this.getter();
   }
 
-  public set(values: readonly string[]) {
+  public async set(values: readonly string[]) {
     if (this.setter === undefined) {
       throw new Error("cannot set read-only register");
     }
 
-    return this.setter(values);
+    await this.setter(values);
+
+    this.notifyChange(Register.ChangeKind.Contents);
   }
 }
 
@@ -310,6 +357,7 @@ class ClipboardRegister extends Register implements Register.Readable,
   private _lastRawText?: string;
 
   public readonly name = '"';
+  public readonly iconName = "clippy";
   public readonly flags = Register.Flags.CanRead | Register.Flags.CanWrite;
 
   public get() {
@@ -327,6 +375,7 @@ class ClipboardRegister extends Register implements Register.Readable,
 
     this._lastStrings = values;
     this._lastRawText = values.join(newline);
+    this.notifyChange(Register.ChangeKind.Contents);
 
     return vscode.env.clipboard.writeText(this._lastRawText);
   }
@@ -343,19 +392,43 @@ function activeEditor() {
 /**
  * A set of registers.
  */
-export abstract class RegisterSet {
+export abstract class RegisterSet implements vscode.Disposable {
+  private readonly _onRegisterChange
+    = new vscode.EventEmitter<{ register: Register; kind: "added" | "removed"; }>();
+  private readonly _onLastMatchesChange = new vscode.EventEmitter<void>();
+
   private readonly _named = new Map<string, Register>();
   private readonly _letters = Array.from(
     { length: 26 },
-    (_, i) => new GeneralPurposeRegister(String.fromCharCode(97 + i)) as Register,
+    (_, i) => new GeneralPurposeRegister(String.fromCharCode(97 + i), "symbol-text") as Register,
   );
   private readonly _digits = Array.from(
-    { length: 10 },
-    (_, i) => new SpecialRegister((i + 1).toString(), () => Promise.resolve(this._lastMatches[i])),
+    { length: 9 },
+    (_, i) => new SpecialRegister(
+      (i + 1).toString(),
+      "regex",
+      () => Promise.resolve(this._lastMatches[i]),
+      undefined,
+      (fire) => this._onLastMatchesChange.event(fire),
+    ),
   );
 
   private _lastMatches: readonly (readonly string[])[] = [];
 
+  /**
+   * The set of registers.
+   */
+  public get registers() {
+    return new Set(this._named.values());
+  }
+
+  /**
+   * Event fired when a change to the set occurs.
+   */
+  public get onRegisterChange() {
+    return this._onRegisterChange.event;
+  }
+
   /**
    * The '"' (`dquote`) register, mapped to the system clipboard and default
    * register for edit operations.
@@ -365,29 +438,30 @@ export abstract class RegisterSet {
   /**
    * The "/" (`slash`) register, default register for search / regex operations.
    */
-  public readonly slash = new GeneralPurposeRegister("/");
+  public readonly slash = new GeneralPurposeRegister("/", "search-view-icon");
 
   /**
    * The "@" (`arobase`) register, default register for recordings (aka macros).
    */
-  public readonly arobase = new GeneralPurposeRegister("@");
+  public readonly arobase = new GeneralPurposeRegister("@", "record");
 
   /**
    * The "^" (`caret`) register, default register for saving selections.
    */
-  public readonly caret = new GeneralPurposeRegister("^");
+  public readonly caret = new GeneralPurposeRegister("^", "save");
 
   /**
    * The "|" (`pipe`) register, default register for outputs of external
    * commands.
    */
-  public readonly pipe = new GeneralPurposeRegister("|");
+  public readonly pipe = new GeneralPurposeRegister("|", "console");
 
   /**
    * The "%" (`percent`) register, mapped to the name of the current document.
    */
   public readonly percent = new SpecialRegister(
     "%",
+    "file",
     () => Promise.resolve([activeEditor().document.fileName]),
     (values) => {
       if (values.length !== 1) {
@@ -396,6 +470,7 @@ export abstract class RegisterSet {
 
       return vscode.workspace.openTextDocument(values[0]).then(() => {});
     },
+    (fire) => vscode.window.onDidChangeActiveTextEditor(fire),
   );
 
   /**
@@ -403,6 +478,7 @@ export abstract class RegisterSet {
    */
   public readonly dot = new SpecialRegister(
     ".",
+    "selection",
     () => {
       const editor = activeEditor(),
             document = editor.document,
@@ -432,20 +508,25 @@ export abstract class RegisterSet {
         }
       }, noUndoStops).then((succeeded) => EditNotAppliedError.throwIfNotApplied(succeeded));
     },
+    (fire) => vscode.window.onDidChangeTextEditorSelection(fire),
   );
 
   /**
    * The read-only "#" (`hash`) register, mapped to the indices of the current
    * selections.
    */
-  public readonly hash = new SpecialRegister("#", () =>
-    Promise.resolve(activeEditor().selections.map((_, i) => i.toString())),
+  public readonly hash = new SpecialRegister("#", "symbol-numeric",
+    () => Promise.resolve(activeEditor().selections.map((_, i) => i.toString())),
+    undefined,
+    (fire) => vscode.window.onDidChangeTextEditorSelection(fire),
   );
 
   /**
    * The read-only "_" (`underscore`) register, mapped to an empty string.
    */
-  public readonly underscore = new SpecialRegister("_", () => Promise.resolve([""]));
+  public readonly underscore = new SpecialRegister("_", undefined, () =>
+    Promise.resolve([""]),
+  );
 
   /**
    * The ":" (`colon`) register.
@@ -453,7 +534,7 @@ export abstract class RegisterSet {
    * In Kakoune it is mapped to the last entered command, but since we don't
    * have access to that information in Dance, we map it to a prompt.
    */
-  public readonly colon = new SpecialRegister(":", () =>
+  public readonly colon = new SpecialRegister(":", undefined, () =>
     prompt({ prompt: ":" }).then((result) => [result]),
   );
 
@@ -463,6 +544,7 @@ export abstract class RegisterSet {
    */
   public readonly null = new SpecialRegister(
     "null",
+    undefined,
     () => Promise.resolve([]),
     () => Promise.resolve(),
   );
@@ -484,10 +566,25 @@ export abstract class RegisterSet {
       this._named.set(longName, register);
     }
 
+    for (let i = 0; i < this._digits.length; i++) {
+      this._named.set(`${i + 1}`, this._digits[i]);
+    }
+
+    for (let i = 0; i < this._letters.length; i++) {
+      const letter = this._letters[i];
+
+      this._named.set(String.fromCharCode(i + 65), letter);
+      this._named.set(String.fromCharCode(i + 97), letter);
+    }
+
     this._named.set("", this.null);
     this._named.set("null", this.null);
   }
 
+  public dispose() {
+    this._onRegisterChange.dispose();
+  }
+
   /**
    * Returns the register with the given name or identified by the given key if
    * the input is one-character long.
@@ -520,14 +617,6 @@ export abstract class RegisterSet {
         return this.colon;
 
       default:
-        if (charCode >= 97 /* a */ && charCode <= 122 /* z */) {
-          return this._letters[charCode - 97];
-        }
-
-        if (charCode >= 65 /* A */ && charCode <= 90 /* Z */) {
-          return this._letters[charCode - 65];
-        }
-
         if (charCode >= 49 /* 1 */ && charCode <= 57 /* 9 */) {
           return this._digits[charCode - 49];
         }
@@ -536,10 +625,10 @@ export abstract class RegisterSet {
 
     key = key.toLowerCase();
 
-    let register = this._named.get(key.toLowerCase());
+    let register = this._named.get(key);
 
     if (register === undefined) {
-      this._named.set(key, register = new GeneralPurposeRegister(key));
+      this._named.set(key, register = new GeneralPurposeRegister(key, "symbol-text"));
     }
 
     return register;
@@ -568,6 +657,7 @@ export abstract class RegisterSet {
     }
 
     this._lastMatches = transposed;
+    this._onLastMatchesChange.fire();
   }
 }