feat: support for experimental evaluatable expressions (#167)

* Add support for experimental evaluatable expressions

* Lint

Author: zobo

src/extension.ts

@@ -1,4 +1,5 @@
 import { LanguageClient, ServerOptions, LanguageClientOptions, StreamInfo } from 'vscode-languageclient'
+import { EvaluatableExpressionRequest } from './protocol'
 
 import * as vscode from 'vscode'
 import { join } from 'path'
@@ -50,6 +51,29 @@ export function activate(context: vscode.ExtensionContext): void {
 
     languageClient = createClient(config)
     languageClient.start()
+
+    context.subscriptions.push(
+        vscode.languages.registerEvaluatableExpressionProvider('php', {
+            async provideEvaluatableExpression(
+                document: vscode.TextDocument,
+                position: vscode.Position,
+                token: vscode.CancellationToken
+            ): Promise<vscode.EvaluatableExpression | undefined> {
+                // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access
+                if (languageClient.initializeResult?.capabilities.experimental?.xevaluatableExpressionProvider) {
+                    const eer = await languageClient.sendRequest(
+                        EvaluatableExpressionRequest.type,
+                        languageClient.code2ProtocolConverter.asTextDocumentPositionParams(document, position),
+                        token
+                    )
+                    if (eer && eer.expression) {
+                        return new vscode.EvaluatableExpression(eer.range, eer.expression)
+                    }
+                }
+                return undefined
+            },
+        })
+    )
 }
 
 export function deactivate(): Promise<void> | undefined {

src/protocol.ts

@@ -0,0 +1,35 @@
+/* eslint @typescript-eslint/no-empty-object-type: 0 */
+/* eslint @typescript-eslint/no-namespace: 0 */
+import { Range } from 'vscode'
+// import { Range } from 'vscode-languageserver-types'
+import { ProtocolRequestType } from 'vscode-languageserver-protocol/lib/messages'
+import {
+    TextDocumentPositionParams,
+    TextDocumentRegistrationOptions,
+    WorkDoneProgressOptions,
+    WorkDoneProgressParams,
+} from 'vscode-languageclient'
+
+interface EvaluatableExpression {
+    expression?: string
+    range: Range
+}
+
+export interface EvaluatableExpressionOptions extends WorkDoneProgressOptions {}
+
+interface EvaluatableExpressionParams extends TextDocumentPositionParams, WorkDoneProgressParams {}
+
+interface EvaluatableExpressionRegistrationOptions
+    extends TextDocumentRegistrationOptions,
+        EvaluatableExpressionOptions {}
+
+export namespace EvaluatableExpressionRequest {
+    export const method = 'textDocument/xevaluatableExpression'
+    export const type = new ProtocolRequestType<
+        EvaluatableExpressionParams,
+        EvaluatableExpression | null,
+        never,
+        void,
+        EvaluatableExpressionRegistrationOptions
+    >(method)
+}