Implement default problem matcher and task for running Python files.

package.json

@@ -73,12 +73,55 @@
         "workspaceContains:manage.py",
         "workspaceContains:app.py",
         "workspaceContains:.venv",
-        "workspaceContains:.conda"
+        "workspaceContains:.conda",
+        "onCommand:workbench.action.tasks.runTask"
     ],
     "main": "./out/client/extension",
     "browser": "./dist/extension.browser.js",
     "l10n": "./l10n",
     "contributes": {
+        "taskDefinitions": [
+            {
+                "type": "pythonTask",
+                "required": ["task"],
+                "properties": {
+                  "task": {
+                    "type": "string",
+                    "description": "The task to customize"
+                  },
+                  "file": {
+                    "type": "string",
+                    "description": "The file that provides the task. Can be omitted."
+                  }
+                }
+              }
+        ],
+        "problemMatchers":
+        [
+            {
+                "name": "pythonCustomMatcher",
+                "owner": "python",
+                "source": "python",
+                "fileLocation": "autoDetect",
+                "pattern": [
+                    {
+                        "regexp": "^.*File \\\"([^\\\"]|.*)\\\", line (\\d+).*",
+                        "file": 1,
+                        "line": 2,
+                        "severity": 4,
+                        "message": 5
+                    },
+                    {
+                        "regexp": "^.*raise.*$"
+                    },
+                    {
+                        "regexp": "^\\s*(.*)\\s*$",
+                        "message": 1
+                    }
+                ]
+            }
+        ],
+
         "walkthroughs": [
             {
                 "id": "pythonWelcome",

src/client/extension.ts

@@ -28,7 +28,7 @@ initializeFileLogging(logDispose);
 //===============================================
 // loading starts here
 
-import { ProgressLocation, ProgressOptions, window } from 'vscode';
+import { commands, ProgressLocation, ProgressOptions, ShellExecution, Task, tasks, TaskScope, window } from 'vscode';
 import { buildApi } from './api';
 import { IApplicationShell, IWorkspaceService } from './common/application/types';
 import { IDisposableRegistry, IExperimentService, IExtensionContext } from './common/types';
@@ -138,6 +138,50 @@ async function activateUnsafe(
         await Promise.all(nonBlocking);
     })();
 
+    // register task provider for the workspace
+
+    const taskProvider = tasks.registerTaskProvider('pythonTask', {
+        provideTasks: () => {
+            return Promise.resolve([
+                new Task(
+                    { type: 'pythonTask', task: 'defaultTask' },
+                    TaskScope.Workspace,
+                    'Default Task',
+                    'pythonTask',
+                    new ShellExecution('python joke.py'), // Hard coded for now: joke.py is in my ext.host workspace. Could be any file in user's workspace.
+                    '$pythonCustomMatcher', // Use the custom problem matcher defined in package.json
+                ),
+            ]);
+        },
+
+        resolveTask(_task: Task): Task | undefined {
+            return undefined;
+        },
+    });
+
+    context.subscriptions.push(taskProvider);
+
+    commands.executeCommand('workbench.action.tasks.registerTaskDefinition', {
+        label: '$pythonCustomMatcher',
+        owner: 'python',
+        source: 'python',
+        fileLocation: 'autoDetect',
+        pattern: [
+            {
+                regexp: '^.*File \\"([^\\"]|.*)\\", line (\\d+).*',
+                file: 1,
+                line: 2,
+            },
+            {
+                regexp: '^.*raise.*$',
+            },
+            {
+                regexp: '^\\s*(.*)\\s*$',
+                message: 1,
+            },
+        ],
+    });
+
     //===============================================
     // activation ends here