Also support MarkdownString in signature help, #11877

src/vs/editor/common/modes.ts

@@ -285,7 +285,7 @@ export interface ParameterInformation {
 	 * The human-readable doc-comment of this signature. Will be shown
 	 * in the UI but can be omitted.
 	 */
-	documentation?: string;
+	documentation?: string | IMarkdownString;
 }
 /**
  * Represents the signature of something callable. A signature
@@ -302,7 +302,7 @@ export interface SignatureInformation {
 	 * The human-readable doc-comment of this signature. Will be shown
 	 * in the UI but can be omitted.
 	 */
-	documentation?: string;
+	documentation?: string | IMarkdownString;
 	/**
 	 * The parameters of this signature.
 	 */

src/vs/editor/contrib/parameterHints/browser/parameterHintsWidget.ts

@@ -26,6 +26,9 @@ import { IConfigurationChangedEvent } from 'vs/editor/common/config/editorOption
 import { ICursorSelectionChangedEvent } from 'vs/editor/common/controller/cursorEvents';
 import { registerThemingParticipant, HIGH_CONTRAST } from 'vs/platform/theme/common/themeService';
 import { editorHoverBackground, editorHoverBorder } from 'vs/platform/theme/common/colorRegistry';
+import { IOpenerService } from 'vs/platform/opener/common/opener';
+import { IModeService } from 'vs/editor/common/services/modeService';
+import { MarkdownRenderer } from 'vs/editor/contrib/markdown/browser/markdownRenderer';
 
 const $ = dom.$;
 
@@ -170,6 +173,7 @@ export class ParameterHintsWidget implements IContentWidget, IDisposable {
 
 	private static ID = 'editor.widget.parameterHintsWidget';
 
+	private markdownRenderer: MarkdownRenderer;
 	private model: ParameterHintsModel;
 	private keyVisible: IContextKey<boolean>;
 	private keyMultipleSignatures: IContextKey<boolean>;
@@ -187,7 +191,13 @@ export class ParameterHintsWidget implements IContentWidget, IDisposable {
 	// Editor.IContentWidget.allowEditorOverflow
 	allowEditorOverflow = true;
 
-	constructor(private editor: ICodeEditor, @IContextKeyService contextKeyService: IContextKeyService) {
+	constructor(
+		private editor: ICodeEditor,
+		@IContextKeyService contextKeyService: IContextKeyService,
+		@IOpenerService openerService: IOpenerService,
+		@IModeService modeService: IModeService,
+	) {
+		this.markdownRenderer = new MarkdownRenderer(editor, modeService, openerService);
 		this.model = new ParameterHintsModel(editor);
 		this.keyVisible = Context.Visible.bindTo(contextKeyService);
 		this.keyMultipleSignatures = Context.MultipleSignatures.bindTo(contextKeyService);
@@ -325,14 +335,20 @@ export class ParameterHintsWidget implements IContentWidget, IDisposable {
 
 		if (activeParameter && activeParameter.documentation) {
 			const documentation = $('span.documentation');
-			documentation.textContent = activeParameter.documentation;
+			if (typeof activeParameter.documentation === 'string') {
+				documentation.textContent = activeParameter.documentation;
+			} else {
+				documentation.appendChild(this.markdownRenderer.render(activeParameter.documentation));
+			}
 			dom.append(this.docs, $('p', null, documentation));
 		}
 
 		dom.toggleClass(this.signature, 'has-docs', !!signature.documentation);
 
-		if (signature.documentation) {
+		if (typeof signature.documentation === 'string') {
 			dom.append(this.docs, $('p', null, signature.documentation));
+		} else {
+			dom.append(this.docs, this.markdownRenderer.render(signature.documentation));
 		}
 
 		let currentOverload = String(this.currentSignature + 1);
@@ -491,4 +507,4 @@ registerThemingParticipant((theme, collector) => {
 	if (background) {
 		collector.addRule(`.monaco-editor .parameter-hints-widget { background-color: ${background}; }`);
 	}
-});
+});

src/vs/monaco.d.ts

@@ -4459,7 +4459,7 @@ declare module monaco.languages {
 		 * The human-readable doc-comment of this signature. Will be shown
 		 * in the UI but can be omitted.
 		 */
-		documentation?: string;
+		documentation?: string | IMarkdownString;
 	}
 
 	/**
@@ -4477,7 +4477,7 @@ declare module monaco.languages {
 		 * The human-readable doc-comment of this signature. Will be shown
 		 * in the UI but can be omitted.
 		 */
-		documentation?: string;
+		documentation?: string | IMarkdownString;
 		/**
 		 * The parameters of this signature.
 		 */

src/vs/vscode.d.ts

@@ -2458,15 +2458,15 @@ declare module 'vscode' {
 		 * The human-readable doc-comment of this signature. Will be shown
 		 * in the UI but can be omitted.
 		 */
-		documentation?: string;
+		documentation?: string | MarkdownString;
 
 		/**
 		 * Creates a new parameter information object.
 		 *
 		 * @param label A label string.
 		 * @param documentation A doc string.
 		 */
-		constructor(label: string, documentation?: string);
+		constructor(label: string, documentation?: string | MarkdownString);
 	}
 
 	/**
@@ -2486,7 +2486,7 @@ declare module 'vscode' {
 		 * The human-readable doc-comment of this signature. Will be shown
 		 * in the UI but can be omitted.
 		 */
-		documentation?: string;
+		documentation?: string | MarkdownString;
 
 		/**
 		 * The parameters of this signature.
@@ -2499,7 +2499,7 @@ declare module 'vscode' {
 		 * @param label A label string.
 		 * @param documentation A doc string.
 		 */
-		constructor(label: string, documentation?: string);
+		constructor(label: string, documentation?: string | MarkdownString);
 	}
 
 	/**

src/vs/workbench/api/node/extHost.api.impl.ts

@@ -53,7 +53,6 @@ import { TextEditorCursorStyle } from 'vs/editor/common/config/editorOptions';
 import { ExtHostThreadService } from 'vs/workbench/services/thread/node/extHostThreadService';
 import { ProxyIdentifier } from 'vs/workbench/services/thread/common/threadService';
 import { ExtHostDialogs } from 'vs/workbench/api/node/extHostDialogs';
-import { MarkdownString } from 'vs/base/common/htmlContent';
 
 export interface IExtensionApiFactory {
 	(extension: IExtensionDescription): typeof vscode;
@@ -567,7 +566,7 @@ export function createApiFactory(
 			Hover: extHostTypes.Hover,
 			IndentAction: languageConfiguration.IndentAction,
 			Location: extHostTypes.Location,
-			MarkdownString: MarkdownString,
+			MarkdownString: extHostTypes.MarkdownString,
 			OverviewRulerLane: EditorCommon.OverviewRulerLane,
 			ParameterInformation: extHostTypes.ParameterInformation,
 			Position: extHostTypes.Position,

src/vs/workbench/api/node/extHostTypeConverters.ts

@@ -354,7 +354,7 @@ export namespace Suggest {
 		result.insertText = suggestion.insertText;
 		result.kind = CompletionItemKind.to(suggestion.type);
 		result.detail = suggestion.detail;
-		result.documentation = typeof suggestion.documentation === 'string' ? suggestion.documentation : MarkdownString.to(suggestion.documentation);
+		result.documentation = htmlContent.isMarkdownString(suggestion.documentation) ? MarkdownString.to(suggestion.documentation) : suggestion.documentation;
 		result.sortText = suggestion.sortText;
 		result.filterText = suggestion.filterText;
 
@@ -381,14 +381,56 @@ export namespace Suggest {
 	}
 };
 
+export namespace ParameterInformation {
+	export function from(info: types.ParameterInformation): modes.ParameterInformation {
+		return {
+			label: info.label,
+			documentation: info.documentation && MarkdownString.from(info.documentation)
+		};
+	}
+	export function to(info: modes.ParameterInformation): types.ParameterInformation {
+		return {
+			label: info.label,
+			documentation: htmlContent.isMarkdownString(info.documentation) ? MarkdownString.to(info.documentation) : info.documentation
+		};
+	}
+}
+
+export namespace SignatureInformation {
+
+	export function from(info: types.SignatureInformation): modes.SignatureInformation {
+		return {
+			label: info.label,
+			documentation: info.documentation && MarkdownString.from(info.documentation),
+			parameters: info.parameters && info.parameters.map(ParameterInformation.from)
+		};
+	}
+
+	export function to(info: modes.SignatureInformation): types.SignatureInformation {
+		return {
+			label: info.label,
+			documentation: htmlContent.isMarkdownString(info.documentation) ? MarkdownString.to(info.documentation) : info.documentation,
+			parameters: info.parameters && info.parameters.map(ParameterInformation.to)
+		};
+	}
+}
+
 export namespace SignatureHelp {
 
-	export function from(signatureHelp: types.SignatureHelp): modes.SignatureHelp {
-		return signatureHelp;
+	export function from(help: types.SignatureHelp): modes.SignatureHelp {
+		return {
+			activeSignature: help.activeSignature,
+			activeParameter: help.activeParameter,
+			signatures: help.signatures && help.signatures.map(SignatureInformation.from)
+		};
 	}
 
-	export function to(hints: modes.SignatureHelp): types.SignatureHelp {
-		return hints;
+	export function to(help: modes.SignatureHelp): types.SignatureHelp {
+		return {
+			activeSignature: help.activeSignature,
+			activeParameter: help.activeParameter,
+			signatures: help.signatures && help.signatures.map(SignatureInformation.to)
+		};
 	}
 }
 

src/vs/workbench/api/node/extHostTypes.ts

@@ -824,12 +824,33 @@ export class CodeLens {
 	}
 }
 
+export class MarkdownString {
+
+	value: string;
+	isTrusted?: boolean;
+
+	constructor(value?: string) {
+		this.value = value || '';
+	}
+
+	appendText(value: string): MarkdownString {
+		// escape markdown syntax tokens: http://daringfireball.net/projects/markdown/syntax#backslash
+		this.value += value.replace(/[\\`*_{}[\]()#+\-.!]/g, '\\$&');
+		return this;
+	}
+
+	appendMarkdown(value: string): MarkdownString {
+		this.value += value;
+		return this;
+	}
+}
+
 export class ParameterInformation {
 
 	label: string;
-	documentation?: string;
+	documentation?: string | MarkdownString;
 
-	constructor(label: string, documentation?: string) {
+	constructor(label: string, documentation?: string | MarkdownString) {
 		this.label = label;
 		this.documentation = documentation;
 	}
@@ -838,10 +859,10 @@ export class ParameterInformation {
 export class SignatureInformation {
 
 	label: string;
-	documentation?: string;
+	documentation?: string | MarkdownString;
 	parameters: ParameterInformation[];
 
-	constructor(label: string, documentation?: string) {
+	constructor(label: string, documentation?: string | MarkdownString) {
 		this.label = label;
 		this.documentation = documentation;
 		this.parameters = [];
@@ -892,7 +913,7 @@ export class CompletionItem {
 	label: string;
 	kind: CompletionItemKind;
 	detail: string;
-	documentation: string | vscode.MarkdownString;
+	documentation: string | MarkdownString;
 	sortText: string;
 	filterText: string;
 	insertText: string | SnippetString;

src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts

@@ -811,7 +811,11 @@ suite('ExtHostLanguageFeatures', function () {
 
 		disposables.push(extHost.registerSignatureHelpProvider(defaultSelector, <vscode.SignatureHelpProvider>{
 			provideSignatureHelp(): vscode.SignatureHelp {
-				return new types.SignatureHelp();
+				return {
+					signatures: [],
+					activeParameter: 0,
+					activeSignature: 0
+				};
 			}
 		}, []));