debug adapter: add interactive variables as a field to package.json

src/vs/workbench/parts/debug/common/debug.ts

@@ -229,6 +229,7 @@ export interface IRawAdapter extends IRawEnvAdapter {
 	enableBreakpointsFor?: { languageIds: string[] };
 	configurationAttributes?: any;
 	initialConfigurations?: any[];
+	variables: { [key: string]: string };
 	aiKey?: string;
 	win?: IRawEnvAdapter;
 	winx86?: IRawEnvAdapter;

src/vs/workbench/parts/debug/node/debugAdapter.ts

@@ -20,6 +20,7 @@ export class Adapter {
 	private _label: string;
 	private configurationAttributes: any;
 	public initialConfigurations: any[];
+	public variables: { [key: string]: string };
 	public enableBreakpointsFor: { languageIds: string[] };
 	public aiKey: string;
 
@@ -65,6 +66,7 @@ export class Adapter {
 		}
 
 		this.type = rawAdapter.type;
+		this.variables = rawAdapter.variables;
 		this.configurationAttributes = rawAdapter.configurationAttributes;
 		this.initialConfigurations = rawAdapter.initialConfigurations;
 		this._label = rawAdapter.label;

src/vs/workbench/parts/debug/node/debugConfigurationManager.ts

@@ -74,6 +74,10 @@ export var debuggersExtPoint = extensionsRegistry.ExtensionsRegistry.registerExt
 				description: nls.localize('vscode.extension.contributes.debuggers.runtimeArgs', "Optional runtime arguments."),
 				type: 'array'
 			},
+			variables : {
+				description: nls.localize('vscode.extension.contributes.debuggers.variables', "Mapping from interactive variables (e.g ${action.pickProcess}) in `launch.json` to a command."),
+				type: 'object'
+			},
 			initialConfigurations: {
 				description: nls.localize('vscode.extension.contributes.debuggers.initialConfigurations', "Configurations for generating the initial \'launch.json\'."),
 				type: 'array',

src/vs/workbench/parts/debug/test/node/debugAdapter.test.ts

@@ -37,7 +37,7 @@ suite('Debug - Adapter', () => {
 				}
 			}
 		},
-
+		variables: null,
 		initialConfigurations: [
 			{
 				name: 'Mock-Debug',