docs: update VS Code debugger configuration descriptions (#12335)

doc/vscode.md

@@ -47,13 +47,16 @@ edit the variable.
 
 ### Setup Debugging
 
+#### Step1: Configure the launch.json file
 1. Install the [C/C++ Extension](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cpptools)
 2. Open `RUN AND DEBUG` panel (Debug Icon in left panel).
 3. Click on `Show` all automatic debug configurations.
 4. Select `Add config`.
 5. Select environment `C++ (GDB/LLDB)`.
 6. Change the line `"program": "Enter the program name, e.g. \"${workspaceFolder}/a.out\"",`
-to point to your compiled application e.g. `"program": "${workspaceFolder}/hello",`.
+to point to your compiled application e.g. `"program": "${workspaceFolder}/hello",`
+or a more flexible one `"program": "${fileDirname}/${fileBasenameNoExtension}",`
+when you want to debug the current opened file.
 
 This will add a block to your `.workspace` file,
 or create the file `.vscode/launch.json`:
@@ -62,7 +65,7 @@ or create the file `.vscode/launch.json`:
     // Use IntelliSense to learn about possible attributes.
     // Hover to view descriptions of existing attributes.
     // For more information, visit: 
-	// https://go.microsoft.com/fwlink/?linkid=830387
+    // https://go.microsoft.com/fwlink/?linkid=830387
     "version": "0.2.0",
     "configurations": [
         {
@@ -75,7 +78,8 @@ or create the file `.vscode/launch.json`:
             "cwd": "${fileDirname}",
             "environment": [],
             "externalConsole": false,
-            "MIMode": "lldb"
+            "MIMode": "lldb",
+	    "preLaunchTask": "build"
         }
     ]
 }
@@ -84,21 +88,52 @@ or create the file `.vscode/launch.json`:
 **Optional:** use `"program": "${fileDirname}/${fileBasenameNoExtension}"` to debug 
 any current open source file with an existing binary with the same name but without any extension.
 
+#### Step2: Configure the task.json file
+Generally, you can manually compile the application with: `v -b c -g hello.v -o hello`,
+or for short: `v -g hello.v`, and then call the debugger.
+
+The `-g` option will add the needed debugging information.
+You can find more debugging options in the [docs](docs.md#debugging).
+
+VS Code provides a hook called `preLaunchTask`, which can be used to compile
+the application automatially every time you call the debugger. 
+[preLaunchTask](https://code.visualstudio.com/docs/editor/debugging#_launchjson-attributes) launches
+a task before the start of a debug session, set this attribute to the label of a task specified
+in [task.json](https://code.visualstudio.com/docs/editor/tasks) (in the workspace's .vscode folder).
+Or, this can be set to `${defaultBuildTask}`, to use your default build task.
+
+As explained, the `"preLaunchTask": "build"` needs to work with a `.vscode/task.json`
+with a label named `build`. 
+```json
+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "build",
+            "type": "shell",
+            "command": "v",
+            "args": [
+                "-g",		    // add more compiler options here if necessary
+                "${relativeFile}"   // or modify it according to your requirements
+            ],
+            "group": "build",
+            "presentation": {
+                "reveal": "silent"
+            },
+            "problemMatcher": "$gcc"
+        }
+    ]
+}
+```
+
 ### Usage
 
 To allow your compiled application to be debugged.
 The application needs to include additional debugging information
 ([DWARF](https://en.wikipedia.org/wiki/DWARF)).
 
-**1. Compile with debugging information:**
-`v -b c -g hello.v -o hello` or short `v -g hello.v`
-
-The `-g` option will add the needed debugging informations.
-More Options are explained in the [docs](docs.md#debugging).
-
-
-**2. Start Debugging**
-
 1. Open your source code and set the required break points
 2. Click on the Debug Icon in the left Icon panel and click
 `> (lldb) Start`, or use `F5` to launch your application in debug mode.