Add a new and improved syntax tree viewer

editors/code/src/commands.ts

@@ -31,6 +31,7 @@ import type { LanguageClient } from "vscode-languageclient/node";
 import { HOVER_REFERENCE_COMMAND } from "./client";
 import type { DependencyId } from "./dependencies_provider";
 import { log } from "./util";
+import type { SyntaxElement } from "./syntax_tree_provider";
 
 export * from "./ast_inspector";
 export * from "./run";
@@ -357,6 +358,38 @@ export async function execRevealDependency(e: RustEditor): Promise<void> {
     await vscode.commands.executeCommand("rust-analyzer.revealDependency", e);
 }
 
+export function syntaxTreeReveal(): Cmd {
+    return async (element: SyntaxElement) => {
+        const activeEditor = vscode.window.activeTextEditor;
+
+        if (activeEditor !== undefined) {
+            const start = activeEditor.document.positionAt(element.start);
+            const end = activeEditor.document.positionAt(element.end);
+
+            const newSelection = new vscode.Selection(start, end);
+
+            activeEditor.selection = newSelection;
+            activeEditor.revealRange(newSelection);
+        }
+    };
+}
+
+export function syntaxTreeHideWhitespace(ctx: CtxInit): Cmd {
+    return async () => {
+        if (ctx.syntaxTreeProvider !== undefined) {
+            await ctx.syntaxTreeProvider.toggleWhitespace();
+        }
+    };
+}
+
+export function syntaxTreeShowWhitespace(ctx: CtxInit): Cmd {
+    return async () => {
+        if (ctx.syntaxTreeProvider !== undefined) {
+            await ctx.syntaxTreeProvider.toggleWhitespace();
+        }
+    };
+}
+
 export function ssr(ctx: CtxInit): Cmd {
     return async () => {
         const editor = vscode.window.activeTextEditor;

editors/code/src/config.ts

@@ -351,6 +351,10 @@ export class Config {
         return this.get<boolean>("showDependenciesExplorer");
     }
 
+    get showSyntaxTree() {
+        return this.get<boolean>("showSyntaxTree");
+    }
+
     get statusBarClickAction() {
         return this.get<string>("statusBar.clickAction");
     }

editors/code/src/ctx.ts

@@ -19,6 +19,7 @@ import {
     RustDependenciesProvider,
     type DependencyId,
 } from "./dependencies_provider";
+import { SyntaxTreeProvider, type SyntaxElement } from "./syntax_tree_provider";
 import { execRevealDependency } from "./commands";
 import { PersistentState } from "./persistent_state";
 import { bootstrap } from "./bootstrap";
@@ -85,7 +86,11 @@ export class Ctx implements RustAnalyzerExtensionApi {
     private commandDisposables: Disposable[];
     private unlinkedFiles: vscode.Uri[];
     private _dependenciesProvider: RustDependenciesProvider | undefined;
-    private _dependencyTreeView: vscode.TreeView<Dependency | DependencyFile | DependencyId> | undefined;
+    private _dependencyTreeView:
+        | vscode.TreeView<Dependency | DependencyFile | DependencyId>
+        | undefined;
+    private _syntaxTreeProvider: SyntaxTreeProvider | undefined;
+    private _syntaxTreeView: vscode.TreeView<SyntaxElement> | undefined;
     private lastStatus: ServerStatusParams | { health: "stopped" } = { health: "stopped" };
     private _serverVersion: string;
     private statusBarActiveEditorListener: Disposable;
@@ -110,6 +115,14 @@ export class Ctx implements RustAnalyzerExtensionApi {
         return this._dependenciesProvider;
     }
 
+    get syntaxTreeView() {
+        return this._syntaxTreeView;
+    }
+
+    get syntaxTreeProvider() {
+        return this._syntaxTreeProvider;
+    }
+
     constructor(
         readonly extCtx: vscode.ExtensionContext,
         commandFactories: Record<string, CommandFactory>,
@@ -278,6 +291,9 @@ export class Ctx implements RustAnalyzerExtensionApi {
         if (this.config.showDependenciesExplorer) {
             this.prepareTreeDependenciesView(client);
         }
+        if (this.config.showSyntaxTree) {
+            this.prepareSyntaxTreeView(client);
+        }
     }
 
     private prepareTreeDependenciesView(client: lc.LanguageClient) {
@@ -326,6 +342,56 @@ export class Ctx implements RustAnalyzerExtensionApi {
         );
     }
 
+    private prepareSyntaxTreeView(client: lc.LanguageClient) {
+        const ctxInit: CtxInit = {
+            ...this,
+            client: client,
+        };
+        this._syntaxTreeProvider = new SyntaxTreeProvider(ctxInit);
+        this._syntaxTreeView = vscode.window.createTreeView("rustSyntaxTree", {
+            treeDataProvider: this._syntaxTreeProvider,
+            showCollapseAll: true,
+        });
+
+        this.pushExtCleanup(this._syntaxTreeView);
+
+        vscode.window.onDidChangeActiveTextEditor(async () => {
+            if (this.syntaxTreeView?.visible) {
+                await this.syntaxTreeProvider?.refresh();
+            }
+        });
+
+        vscode.workspace.onDidChangeTextDocument(async () => {
+            if (this.syntaxTreeView?.visible) {
+                await this.syntaxTreeProvider?.refresh();
+            }
+        });
+
+        vscode.window.onDidChangeTextEditorSelection(async (e) => {
+            if (!this.syntaxTreeView?.visible || !isRustEditor(e.textEditor)) {
+                return;
+            }
+
+            const selection = e.selections[0];
+            if (selection === undefined) {
+                return;
+            }
+
+            const start = e.textEditor.document.offsetAt(selection.start);
+            const end = e.textEditor.document.offsetAt(selection.end);
+            const result = this.syntaxTreeProvider?.getElementByRange(start, end);
+            if (result !== undefined) {
+                await this.syntaxTreeView?.reveal(result);
+            }
+        });
+
+        this._syntaxTreeView.onDidChangeVisibility(async (e) => {
+            if (e.visible) {
+                await this.syntaxTreeProvider?.refresh();
+            }
+        });
+    }
+
     async restart() {
         // FIXME: We should re-use the client, that is ctx.deactivate() if none of the configs have changed
         await this.stopAndDispose();
@@ -424,6 +490,7 @@ export class Ctx implements RustAnalyzerExtensionApi {
                     statusBar.command = "rust-analyzer.openLogs";
                 }
                 this.dependenciesProvider?.refresh();
+                void this.syntaxTreeProvider?.refresh();
                 break;
             case "warning":
                 statusBar.color = new vscode.ThemeColor("statusBarItem.warningForeground");

editors/code/src/lsp_ext.ts

@@ -48,6 +48,9 @@ export const runFlycheck = new lc.NotificationType<{
 export const syntaxTree = new lc.RequestType<SyntaxTreeParams, string, void>(
     "rust-analyzer/syntaxTree",
 );
+export const viewSyntaxTree = new lc.RequestType<ViewSyntaxTreeParams, string, void>(
+    "rust-analyzer/viewSyntaxTree",
+);
 export const viewCrateGraph = new lc.RequestType<ViewCrateGraphParams, string, void>(
     "rust-analyzer/viewCrateGraph",
 );
@@ -157,6 +160,7 @@ export type SyntaxTreeParams = {
     textDocument: lc.TextDocumentIdentifier;
     range: lc.Range | null;
 };
+export type ViewSyntaxTreeParams = { textDocument: lc.TextDocumentIdentifier };
 export type ViewCrateGraphParams = { full: boolean };
 export type ViewItemTreeParams = { textDocument: lc.TextDocumentIdentifier };
 

editors/code/src/main.ts

@@ -199,6 +199,9 @@ function createCommands(): Record<string, CommandFactory> {
         rename: { enabled: commands.rename },
         openLogs: { enabled: commands.openLogs },
         revealDependency: { enabled: commands.revealDependency },
+        syntaxTreeReveal: { enabled: commands.syntaxTreeReveal },
+        syntaxTreeHideWhitespace: { enabled: commands.syntaxTreeHideWhitespace },
+        syntaxTreeShowWhitespace: { enabled: commands.syntaxTreeShowWhitespace },
     };
 }
 

editors/code/src/syntax_tree_provider.ts

@@ -0,0 +1,301 @@
+import * as vscode from "vscode";
+
+import { isRustEditor, setContextValue } from "./util";
+import type { CtxInit } from "./ctx";
+import * as ra from "./lsp_ext";
+
+export class SyntaxTreeProvider implements vscode.TreeDataProvider<SyntaxElement> {
+    private _onDidChangeTreeData: vscode.EventEmitter<SyntaxElement | undefined | void> =
+        new vscode.EventEmitter<SyntaxElement | undefined | void>();
+    readonly onDidChangeTreeData: vscode.Event<SyntaxElement | undefined | void> =
+        this._onDidChangeTreeData.event;
+    ctx: CtxInit;
+    root: SyntaxNode | undefined;
+    hideWhitespace: boolean = false;
+
+    constructor(ctx: CtxInit) {
+        this.ctx = ctx;
+    }
+
+    getTreeItem(element: SyntaxElement): vscode.TreeItem {
+        return new SyntaxTreeItem(element);
+    }
+
+    getChildren(element?: SyntaxElement): vscode.ProviderResult<SyntaxElement[]> {
+        return this.getRawChildren(element);
+    }
+
+    getParent(element: SyntaxElement): vscode.ProviderResult<SyntaxElement> {
+        return element.parent;
+    }
+
+    resolveTreeItem(
+        item: SyntaxTreeItem,
+        element: SyntaxElement,
+        _token: vscode.CancellationToken,
+    ): vscode.ProviderResult<SyntaxTreeItem> {
+        const editor = vscode.window.activeTextEditor;
+
+        if (editor !== undefined) {
+            const start = editor.document.positionAt(element.start);
+            const end = editor.document.positionAt(element.end);
+            const range = new vscode.Range(start, end);
+
+            const text = editor.document.getText(range);
+            item.tooltip = new vscode.MarkdownString().appendCodeblock(text, "rust");
+        }
+
+        return item;
+    }
+
+    private getRawChildren(element?: SyntaxElement): SyntaxElement[] {
+        if (element?.type === "Node") {
+            if (this.hideWhitespace) {
+                return element.children.filter((e) => e.kind !== "WHITESPACE");
+            }
+
+            return element.children;
+        }
+
+        if (element?.type === "Token") {
+            return [];
+        }
+
+        if (element === undefined && this.root !== undefined) {
+            return [this.root];
+        }
+
+        return [];
+    }
+
+    async refresh(): Promise<void> {
+        const editor = vscode.window.activeTextEditor;
+
+        if (editor && isRustEditor(editor)) {
+            const params = { textDocument: { uri: editor.document.uri.toString() }, range: null };
+            const fileText = await this.ctx.client.sendRequest(ra.viewSyntaxTree, params);
+            this.root = JSON.parse(fileText, (_key, value: SyntaxElement) => {
+                if (value.type === "Node") {
+                    for (const child of value.children) {
+                        child.parent = value;
+                    }
+                }
+
+                return value;
+            });
+        } else {
+            this.root = undefined;
+        }
+
+        this._onDidChangeTreeData.fire();
+    }
+
+    getElementByRange(start: number, end: number): SyntaxElement | undefined {
+        if (this.root === undefined) {
+            return undefined;
+        }
+
+        let result: SyntaxElement = this.root;
+
+        if (this.root.start === start && this.root.end === end) {
+            return result;
+        }
+
+        let children = this.getRawChildren(this.root);
+
+        outer: while (true) {
+            for (const child of children) {
+                if (child.start <= start && child.end >= end) {
+                    result = child;
+                    if (start === end && start === child.end) {
+                        // When the cursor is on the very end of a token,
+                        // we assume the user wants the next token instead.
+                        continue;
+                    }
+
+                    if (child.type === "Token") {
+                        return result;
+                    } else {
+                        children = this.getRawChildren(child);
+                        continue outer;
+                    }
+                }
+            }
+
+            return result;
+        }
+    }
+
+    async toggleWhitespace() {
+        this.hideWhitespace = !this.hideWhitespace;
+        this._onDidChangeTreeData.fire();
+        await setContextValue("rustSyntaxTree.hideWhitespace", this.hideWhitespace);
+    }
+}
+
+export type SyntaxNode = {
+    type: "Node";
+    kind: string;
+    start: number;
+    end: number;
+    istart?: number;
+    iend?: number;
+    children: SyntaxElement[];
+    parent?: SyntaxElement;
+};
+
+type SyntaxToken = {
+    type: "Token";
+    kind: string;
+    start: number;
+    end: number;
+    istart?: number;
+    iend?: number;
+    parent?: SyntaxElement;
+};
+
+export type SyntaxElement = SyntaxNode | SyntaxToken;
+
+export class SyntaxTreeItem extends vscode.TreeItem {
+    constructor(private readonly element: SyntaxElement) {
+        super(element.kind);
+        const icon = getIcon(element.kind);
+        if (element.type === "Node") {
+            this.contextValue = "syntaxNode";
+            this.iconPath = icon ?? new vscode.ThemeIcon("list-tree");
+            this.collapsibleState = vscode.TreeItemCollapsibleState.Expanded;
+        } else {
+            this.contextValue = "syntaxToken";
+            this.iconPath = icon ?? new vscode.ThemeIcon("symbol-string");
+            this.collapsibleState = vscode.TreeItemCollapsibleState.None;
+        }
+
+        if (element.istart !== undefined && element.iend !== undefined) {
+            this.description = `${this.element.istart}..${this.element.iend}`;
+        } else {
+            this.description = `${this.element.start}..${this.element.end}`;
+        }
+    }
+}
+
+function getIcon(kind: string): vscode.ThemeIcon | undefined {
+    const icon = iconTable[kind];
+
+    if (icon !== undefined) {
+        return icon;
+    }
+
+    if (kind.endsWith("_KW")) {
+        return new vscode.ThemeIcon(
+            "symbol-keyword",
+            new vscode.ThemeColor("symbolIcon.keywordForeground"),
+        );
+    }
+
+    if (operators.includes(kind)) {
+        return new vscode.ThemeIcon(
+            "symbol-operator",
+            new vscode.ThemeColor("symbolIcon.operatorForeground"),
+        );
+    }
+
+    return undefined;
+}
+
+const iconTable: Record<string, vscode.ThemeIcon> = {
+    CALL_EXPR: new vscode.ThemeIcon("call-outgoing"),
+    COMMENT: new vscode.ThemeIcon("comment"),
+    ENUM: new vscode.ThemeIcon("symbol-enum", new vscode.ThemeColor("symbolIcon.enumForeground")),
+    FN: new vscode.ThemeIcon(
+        "symbol-function",
+        new vscode.ThemeColor("symbolIcon.functionForeground"),
+    ),
+    FLOAT_NUMBER: new vscode.ThemeIcon(
+        "symbol-number",
+        new vscode.ThemeColor("symbolIcon.numberForeground"),
+    ),
+    INDEX_EXPR: new vscode.ThemeIcon(
+        "symbol-array",
+        new vscode.ThemeColor("symbolIcon.arrayForeground"),
+    ),
+    INT_NUMBER: new vscode.ThemeIcon(
+        "symbol-number",
+        new vscode.ThemeColor("symbolIcon.numberForeground"),
+    ),
+    LITERAL: new vscode.ThemeIcon(
+        "symbol-misc",
+        new vscode.ThemeColor("symbolIcon.miscForeground"),
+    ),
+    MODULE: new vscode.ThemeIcon(
+        "symbol-module",
+        new vscode.ThemeColor("symbolIcon.moduleForeground"),
+    ),
+    METHOD_CALL_EXPR: new vscode.ThemeIcon("call-outgoing"),
+    PARAM: new vscode.ThemeIcon(
+        "symbol-parameter",
+        new vscode.ThemeColor("symbolIcon.parameterForeground"),
+    ),
+    RECORD_FIELD: new vscode.ThemeIcon(
+        "symbol-field",
+        new vscode.ThemeColor("symbolIcon.fieldForeground"),
+    ),
+    SOURCE_FILE: new vscode.ThemeIcon("file-code"),
+    STRING: new vscode.ThemeIcon("quote"),
+    STRUCT: new vscode.ThemeIcon(
+        "symbol-struct",
+        new vscode.ThemeColor("symbolIcon.structForeground"),
+    ),
+    TRAIT: new vscode.ThemeIcon(
+        "symbol-interface",
+        new vscode.ThemeColor("symbolIcon.interfaceForeground"),
+    ),
+    TYPE_PARAM: new vscode.ThemeIcon(
+        "symbol-type-parameter",
+        new vscode.ThemeColor("symbolIcon.typeParameterForeground"),
+    ),
+    VARIANT: new vscode.ThemeIcon(
+        "symbol-enum-member",
+        new vscode.ThemeColor("symbolIcon.enumMemberForeground"),
+    ),
+    WHITESPACE: new vscode.ThemeIcon("whitespace"),
+};
+
+const operators = [
+    "PLUS",
+    "PLUSEQ",
+    "MINUS",
+    "MINUSEQ",
+    "STAR",
+    "STAREQ",
+    "SLASH",
+    "SLASHEQ",
+    "PERCENT",
+    "PERCENTEQ",
+    "CARET",
+    "CARETEQ",
+    "AMP",
+    "AMPEQ",
+    "AMP2",
+    "PIPE",
+    "PIPEEQ",
+    "PIPE2",
+    "SHL",
+    "SHLEQ",
+    "SHR",
+    "SHREQ",
+    "EQ",
+    "EQ2",
+    "BANG",
+    "NEQ",
+    "L_ANGLE",
+    "LTEQ",
+    "R_ANGLE",
+    "GTEQ",
+    "COLON2",
+    "THIN_ARROW",
+    "FAT_ARROW",
+    "DOT",
+    "DOT2",
+    "DOT2EQ",
+    "AT",
+];