Add an action to copy an element from the syntax tree view

Author: Giga-Bowser

editors/code/package.json

@@ -289,6 +289,12 @@
                 "icon": "$(search)",
                 "category": "rust-analyzer (syntax tree)"
             },
+            {
+                "command": "rust-analyzer.syntaxTreeCopy",
+                "title": "Copy",
+                "icon": "$(copy)",
+                "category": "rust-analyzer (syntax tree)"
+            },
             {
                 "command": "rust-analyzer.syntaxTreeHideWhitespace",
                 "title": "Hide Whitespace",
@@ -3370,6 +3376,10 @@
                     "command": "rust-analyzer.syntaxTreeReveal",
                     "when": "false"
                 },
+                {
+                    "command": "rust-analyzer.syntaxTreeCopy",
+                    "when": "false"
+                },
                 {
                     "command": "rust-analyzer.syntaxTreeHideWhitespace",
                     "when": "false"
@@ -3404,6 +3414,11 @@
                 }
             ],
             "view/item/context": [
+                {
+                    "command": "rust-analyzer.syntaxTreeCopy",
+                    "group": "inline",
+                    "when": "view == rustSyntaxTree"
+                },
                 {
                     "command": "rust-analyzer.syntaxTreeReveal",
                     "group": "inline",

editors/code/src/commands.ts

@@ -372,6 +372,45 @@ export function syntaxTreeReveal(): Cmd {
     };
 }
 
+function elementToString(
+    activeDocument: vscode.TextDocument,
+    element: SyntaxElement,
+    depth: number = 0,
+): string {
+    let result = "  ".repeat(depth);
+    const start = element.istart ?? element.start;
+    const end = element.iend ?? element.end;
+
+    result += `${element.kind}@${start}..${end}`;
+
+    if (element.type === "Token") {
+        const startPosition = activeDocument.positionAt(element.start);
+        const endPosition = activeDocument.positionAt(element.end);
+        const text = activeDocument.getText(new vscode.Range(startPosition, endPosition));
+        // JSON.stringify quotes and escapes the string for us.
+        result += ` ${JSON.stringify(text)}\n`;
+    } else {
+        result += "\n";
+        for (const child of element.children) {
+            result += elementToString(activeDocument, child, depth + 1);
+        }
+    }
+
+    return result;
+}
+
+export function syntaxTreeCopy(): Cmd {
+    return async (element: SyntaxElement) => {
+        const activeDocument = vscode.window.activeTextEditor?.document;
+        if (!activeDocument) {
+            return;
+        }
+
+        const result = elementToString(activeDocument, element);
+        await vscode.env.clipboard.writeText(result);
+    };
+}
+
 export function syntaxTreeHideWhitespace(ctx: CtxInit): Cmd {
     return async () => {
         if (ctx.syntaxTreeProvider !== undefined) {

editors/code/src/main.ts

@@ -199,6 +199,7 @@ function createCommands(): Record<string, CommandFactory> {
         openLogs: { enabled: commands.openLogs },
         revealDependency: { enabled: commands.revealDependency },
         syntaxTreeReveal: { enabled: commands.syntaxTreeReveal },
+        syntaxTreeCopy: { enabled: commands.syntaxTreeCopy },
         syntaxTreeHideWhitespace: { enabled: commands.syntaxTreeHideWhitespace },
         syntaxTreeShowWhitespace: { enabled: commands.syntaxTreeShowWhitespace },
     };