Basic show syntax tree

package.json

@@ -79,6 +79,11 @@
         "command": "cairo.viewAnalyzedCrates",
         "title": "View currently analyzed crates",
         "category": "Cairo"
+      },
+      {
+        "command": "cairo.viewSyntaxTree",
+        "title": "View syntax tree of the current file content",
+        "category": "Cairo"
       }
     ],
     "configuration": [

src/cairols.ts

@@ -6,6 +6,7 @@ import { Context } from "./context";
 import { Scarb } from "./scarb";
 import {
   registerMacroExpandProvider,
+  registerViewSyntaxTreeProvider,
   registerVfsProvider,
   registerViewAnalyzedCratesProvider,
 } from "./textDocumentProviders";
@@ -71,6 +72,7 @@ export async function setupLanguageServer(ctx: Context): Promise<SetupResult | u
   registerVfsProvider(client, ctx);
   registerMacroExpandProvider(client, ctx);
   registerViewAnalyzedCratesProvider(client, ctx);
+  registerViewSyntaxTreeProvider(client, ctx);
 
   client.onNotification("scarb/could-not-find-scarb-executable", () => notifyScarbMissing(ctx));
 

src/lspRequests.ts

@@ -45,3 +45,15 @@ export interface ToolchainInfoResponse {
 export const toolchainInfo = new lc.RequestType0<ToolchainInfoResponse, void>(
   "cairo/toolchainInfo",
 );
+
+export interface ViewSyntaxTreeRequest {
+  uri: string;
+}
+
+export type ViewSyntaxTreeRequestResponse = string | null;
+
+export const viewSyntaxTree = new lc.RequestType<
+  ViewSyntaxTreeRequest,
+  ViewSyntaxTreeRequestResponse,
+  void
+>("cairo/viewSyntaxTree");

src/textDocumentProviders.ts

@@ -1,7 +1,7 @@
 import * as lc from "vscode-languageclient/node";
 import * as vscode from "vscode";
 import { Context } from "./context";
-import { expandMacro, vfsProvide, viewAnalyzedCrates } from "./lspRequests";
+import { expandMacro, viewSyntaxTree, vfsProvide, viewAnalyzedCrates } from "./lspRequests";
 
 export const registerVfsProvider = (client: lc.LanguageClient, ctx: Context) => {
   const vfsProvider: vscode.TextDocumentContentProvider = {
@@ -94,3 +94,38 @@ export const registerViewAnalyzedCratesProvider = (client: lc.LanguageClient, ct
     }),
   );
 };
+
+export const registerViewSyntaxTreeProvider = (client: lc.LanguageClient, ctx: Context) => {
+  const uri = vscode.Uri.parse("cairo-view-syntax-tree://viewSyntaxTree/[SYNTAX_TREE].txt");
+  const eventEmitter = new vscode.EventEmitter<vscode.Uri>();
+
+  const tdcp: vscode.TextDocumentContentProvider = {
+    async provideTextDocumentContent(): Promise<string> {
+      const editor = vscode.window.activeTextEditor;
+      if (!editor) return "No file selected, please click on a file";
+
+      const syntaxTree = await client.sendRequest(viewSyntaxTree, {
+        uri: client.code2ProtocolConverter.asUri(editor.document.uri),
+      });
+
+      return syntaxTree ?? "Not available";
+    },
+    onDidChange: eventEmitter.event,
+  };
+
+  ctx.extension.subscriptions.push(
+    vscode.workspace.registerTextDocumentContentProvider("cairo-view-syntax-tree", tdcp),
+  );
+
+  ctx.extension.subscriptions.push(
+    vscode.commands.registerCommand("cairo.viewSyntaxTree", async () => {
+      const document = await vscode.workspace.openTextDocument(uri);
+
+      eventEmitter.fire(uri);
+
+      return vscode.window.showTextDocument(document, vscode.ViewColumn.Two, true);
+    }),
+  );
+
+  // TODO: re-request on file change
+};